Patent Publication Number: US-10311744-B2

Title: Autodidactic cognitive training device and method thereof

Description:
PRIORITY CLAIM TO RELATED APPLICATIONS 
     This application is a U.S. National Stage application filed under 35 U.S.C. § 371 from International Application Serial No. PCT/SG2013/000363, which was filed Aug. 22, 2013, and published as WO2014/031083 on Feb. 27, 2014, and which claims priority to Singapore Application No. 201206301-2, filed Aug. 24, 2012, which applications and publication are incorporated by reference as if reproduced herein and made a part hereof in their entirety, and the benefit of priority of each of which is claimed herein. 
     FIELD OF INVENTION 
     The invention relates generally to an autodidactic cognitive training device and method thereof. 
     BACKGROUND 
     Memory loss is a common neurodegenerative condition that comes with aging. It is especially so for patients diagnosed with dementia, which is a set of signs and symptoms affecting the cognitive functions of memory. One such example of, dementia is Alzheimer&#39;s diseases. Approved drugs are used on patients with Alzheimer&#39;s diseases but they do not cure or prevent the symptoms. Therefore, alternative interventions are called for to treat the memory loss of the patients. 
     Trans-cranial direct current stimulation (tDCS) is one such alternative intervention. It is a neuromodulatory method that delivers low-intensity, direct current to cortical areas facilitating or inhibiting spontaneous neuronal activity. However, since tDCS elicits after-effects lasting for up to an hour, it may in some instances cause unnecessary side-effects to the cognitive functions of the subject. 
     With the existing techniques and tools, it is difficult to provide a personalized memory training system that meets the needs of the subject. Each subject has a different degree of affected memory functions, i.e., a patient of dementia may exhibit two or more dementing processes at the same time. 
     It is also possible for a subject to advance in the dementing processes at a different rate, making it difficult to provide an objective assessment of the cognitive functions of memory. An objective cognitive assessment will be helpful to provide a personalized training program to aid in the training of the cognitive functions of a subject. 
     A need therefore exists to provide an objective cognitive assessment which can be used to provide a personalized memory training program. 
     SUMMARY 
     According to a first aspect, there is provided a method for cognitive training, the method comprising obtaining sensor data of a subject during a memory exercise; determining whether the sensor data includes predetermined information indicative of cognitive functions used for remembering; advancing the memory exercise when it is determined that the sensor data includes predetermined information indicative of cognitive functions used for remembering; and calculating an objective cognitive assessment of the subject in response to completion of the memory exercise, wherein cognitive training is measured at least partially in response to the advancing of the memory exercise. 
     According to a second aspect, there is provided an autodidactic cognitive training device comprising an input device for receiving the sensor data of a subject during a memory exercise; a cognitive function evaluator adapted to receive the sensor data from the input device and determine whether the sensor data includes predetermined information indicative of cognitive functions used for remembering; an exercise device adapted to advance the memory exercise when it is determined that the sensor data includes the predetermined information indicative of cognitive functions used for remembering, the exercise device comprising a calculating device adapted to calculate an objective cognitive assessment of the subject in response to completion of the memory exercise. 
     According to a third aspect, there is provided a system comprising two or more devices according to the second aspect as described above wherein the receiver is further operable to receive the objective cognitive assessment of two or more subjects corresponding to the two or more devices and the server operable to correlate the two or more subjects with their respective objective cognitive assessments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which: 
         FIG. 1  shows a flowchart that illustrates a method for cognitive training according to a first embodiment; 
         FIG. 2  shows an autodidactic cognitive training device, according to a second embodiment; 
         FIG. 3  shows a picture of a setup for brain computer interface training; 
         FIG. 4  shows a plan view of a memory exercise; 
         FIG. 5  shows a graphical representation of the change in difficulty level and the time taken; 
         FIG. 6  shows a graphical representation of the change in number of cards and the difficulty level; 
         FIG. 7  shows a block diagram of autodidactic cognitive training devices in a system. 
     
    
    
     DETAILED DESCRIPTION 
     Some portions of the description which follows are explicitly or implicitly presented in terms of algorithms and functional or symbolic representations of operations on data within a computer memory. These algorithmic descriptions and functional or symbolic representations are the means used by those skilled in the data processing arts to convey most effectively the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities, such as electrical, magnetic or optical signals capable of being stored, transferred, combined, compared, and otherwise manipulated. 
     Unless specifically stated otherwise, and as apparent from the following, it will be appreciated that throughout the present specification, discussions utilizing terms such as “scanning”, “calculating”, “determining”, “replacing”, “generating”, “initializing”, “outputting”, or the like, refer to the action and processes of a computer system, or similar electronic device, that manipulates and transforms data represented as physical quantities within the computer system into other data similarly represented as physical quantities within the computer system or other information storage, transmission or display devices. 
     The present specification also discloses apparatus for performing the operations of the methods. Such apparatus may be specially constructed for the required purposes, or may comprise a general purpose computer or other device selectively activated or reconfigured by a computer program stored in the computer. The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose machines may be used with programs in accordance with the teachings herein. Alternatively, the construction of more specialized apparatus to perform the required method steps may be appropriate. The structure of a conventional general purpose computer will appear from the description below. 
     In addition, the present specification also implicitly discloses a computer program, in that it would be apparent to the person skilled in the art that the individual steps of the method described herein may be put into effect by computer code. The computer program is not intended to be limited to any particular programming language and implementation thereof. It will be appreciated that a variety of programming languages and coding thereof may be used to implement the teachings of the disclosure contained herein. Moreover, the computer program is not intended to be limited to any particular control flow. There are many other variants of the computer program, which can use different control flows without departing from the spirit or scope of the invention. 
     Furthermore, one or more of the steps of the computer program may be performed in parallel rather than sequentially. Such a computer program may be stored on any computer readable medium. The computer readable medium may include storage devices such as magnetic or optical disks, memory chips, or other storage devices suitable for interfacing with a general purpose computer. The computer readable medium may also include a hard-wired medium such as exemplified in the Internet system, or wireless medium such as exemplified in the GSM mobile telephone system. The computer program when loaded and executed on such a general-purpose computer effectively results in an apparatus that implements the steps of the preferred method. 
     The invention may also be implemented as hardware modules. More particular, in the hardware sense, a module is a functional hardware unit designed for use with other components or modules. For example, a module may, be implemented using discrete electronic components, or it can form a portion of an entire electronic circuit such as an Application Specific Integrated Circuit (ASIC). Numerous other possibilities exist. Those skilled in the art will appreciate that the system can also be implemented as a combination of hardware and software modules. 
       FIG. 1  shows a flowchart  100  that illustrates a method for cognitive training according to a first embodiment. This methodology provides cognitive training for a subject in a personalized manner. 
     In step  102 , sensor data relating to a subject is obtained. In step  104 , it will be determined whether or not the sensor data includes predetermined information indicative of cognitive functions used for remembering. In an embodiment, the sensor data could come from physiological and/or behavioral sensor. In another embodiment, the sensor data could come from video camera and/or electroencephalography (EEG) electrode. In step  106 , the memory exercise is advanced. In step  108 , it will be determined whether or not the memory exercise is completed. In step  110 , an objective cognitive assessment is calculated. 
     In step  104 , the obtained sensor data from step  102  will be compared with predetermined information indicative of cognitive functions used for remembering to determine whether or not the sensor data includes the predetermined information. The presence of the predetermined information indicates that the subject is using cognitive functions for remembering. 
     When it is determined that the sensor data includes predetermined information indicative of cognitive functions used for remembering, the memory exercise will advance in step  106 . In, the event that it is determined that the sensor data does not include predetermined information indicative of cognitive functions used for remembering, step  104  will be repeated until it is determined that the sensor data includes the predetermined information indicative of cognitive functions for remembering: 
     The determining step includes determining when a predetermined portion of the memory exercise is completed in predetermined time duration. In one instance, an indicator is provided to illustrate to the subject the progress of completing the portion of the memory exercise within the predetermined time duration. The indicator may be a visual signal, light signal or an audio signal. In the event that the portion of the memory exercise is not completed within the predetermined time duration, step  104  will be repeated and the indicator will indicate the same to the subject. 
     The determining step includes whether a score is achieved for a current level of the memory exercise in step  104  before the memory exercise will advance in step  106 . The score is taken based on several parameters, i.e., time taken to complete the memory exercise, the complexity and difficulty of the exercise, accuracy of the subject, profile and condition of the subject. The score can be adjusted according to the requirements of the subject. The score indicates a measure of the cognitive function used for remembering when at least a portion of the memory exercise is completed. 
     In step  108 , it is determined whether the memory exercise is completed. When it is determined that the memory exercise is completed, step  110  is invoked. The results from step  110  provide for a value that is an objective assessment of the cognitive ability for remembering of the subject, based on documented parameters suitable for the subject and the performance of the subject during the exercise, i.e., time taken to complete the exercise and the accuracy. The objective cognitive assessment obtained in step  108  can be used to adjust the predetermined information that is used in the determining step  104 . 
     The performance of the subject for the completed memory exercise will be assessed in response of the calculated objective cognitive assessment. The subject profile will be updated accordingly in response to the objective cognitive assessment. This allows the clinical professionals to keep track of the progress of the training. 
     The memory exercise is then configured in response to the objective cognitive assessment of the subject and the subject profile. This provides a personalized cognitive training method for the subject in accordance to the condition and needs of the subject. The predetermined information that is used in the determining step will also be adjusted accordingly. If the subject has completed the memory exercise before the expected time duration, the predetermined duration that is used in determining whether the sensor data includes the predetermined information will be shortened and the reverse applies. If the subject were to take a longer time to complete the memory exercise than expected, the predetermined information that is used in analyzing the sensor data will be adjusted accordingly. In this manner, a personalized memory exercise will be provided. 
       FIG. 2  shows an apparatus  200 , according to a second embodiment for cognitive training. Sensor data is acquired via an input device  203 . An example of the input device  203  is an electrode that is attached to the forehead of the subject, as illustrated in  FIG. 3 . In one embodiment, the input device  203  could be physiological and/or behavioral sensor. In another embodiment, the input device  203  could be a video camera and/or electroencephalography (EEG) electrode. 
     The input device  203  is arranged to be coupled to the cognitive function evaluator  206 . The cognitive function evaluator  206  is adapted to determine whether the sensor data includes predetermined information indicative for remembering. 
     The cognitive function evaluator  206  is further adapted to determine when a predetermined portion of the memory exercise is completed in predetermined time duration. In one instance, an indicator is provided to illustrate to the subject the progress of completing the portion of the memory exercise within the predetermined time duration. The indicator may be a visual signal, light signal or an audio signal. In the event that the portion of the memory exercise is not completed within the predetermined time duration, the cognitive function evaluator will repeat the determining step and the indicator will indicate the same to the subject. 
     In an embodiment, there is a sensor signal translator  204  that is adapted to translate the acquired sensor data via input device  203  for use in the cognitive function evaluator  206  to determine whether the translated sensor data includes the predetermined information indicative of cognitive functions for remembering. In another embodiment, the sensor signal translator  204  could be an EEG translator and could be adapted to translate the acquired EEG data for use in the cognitive function evaluation  206  to determine whether the translated sensor data includes the predetermined information indicative of cognitive functions for remembering. 
     In an embodiment, the cognitive function evaluator  206  comprises a filter  205 . The sensor data received from the input device  203  or sensor signal translator  204  will be passed through the filter  205  before the cognitive function evaluator  206  determines whether the sensor data includes the predetermined information. 
     The cognitive function evaluator  206  is coupled to an exercise device  208 . The exercise device  208  is adapted to advance the memory exercise when it is determined that the sensor data includes the predetermined information indicative of cognitive functions used for remembering. The exercise device  208  is adapted not to advance when it is determined that the sensor data does not include the predetermined information indicative of cognitive functions used for remembering. The exercise device  208  is adapted to determine whether or not a score is achieved for a current level of the memory device and advance the memory exercise accordance with machine learning techniques when it is determined that the score is achieved for the current level of the memory exercise. The score indicates a measure of the cognitive function used for remembering when at least a portion of the memory exercise is completed. 
     The exercise device  208  includes a calculating device  209  that is adapted to calculate an objective cognitive assessment of the subject in accordance with probabilistic modeling when it is determined by the exercise device that the memory device is completed. In an embodiment, the calculating device  209  calculates the objective cognitive assessment of the subject in response to the performance and/or score of the subject, i.e., time taken to complete the memory exercise, accuracy of the performance. 
     The exercise device  208  is coupled to a cognitive assessor  210  that is adapted to receive the calculated objective cognitive assessment of the subject. The cognitive assessor  210  assesses the performance of the subject for the memory device in response to the calculated objective cognitive assessment. 
     The cognitive assessor  210  is coupled to an optimizer  212  which is adapted to store information including the sensor data from input device  203  and the sensor signal translator  201 , parameters pertaining to the memory exercise, and a subject profile corresponding to the subject. The subject profile includes the condition and historic objective cognitive assessment from completing the memory exercises. The optimizer  212  is adapted to receive the assessed objective cognitive assessment and update the subject profile accordingly in response to the objective cognitive assessment. This allows the clinical professionals to keep track of the progress of the training. 
     The optimizer  212  is coupled to a configurator  214  which is adapted to configure the memory exercise in response to the assessed objective cognitive assessment of the subject and the subject profile. This provides a personalized cognitive training method for the subject in accordance to the condition and needs of the subject. In one embodiment, the configurator  214  adjusts the predetermined information that is used in the determining step by the cognitive function evaluator  206  in response to the assessed objective cognitive assessment. If the subject has completed the memory exercise before the expected time duration, the predetermined duration that is used in determining whether the sensor data includes the predetermined information will be shortened and the reverse applies. If the subject were to take a longer time to complete the memory exercise than expected, the predetermined information that is used in analyzing the sensor data will be adjusted accordingly. 
     In one embodiment, the configurator.  214  will configure the predetermined duration that is used in determining whether the sensor data includes the predetermined duration in response to the assessed objective assessment. If the subject has completed the memory exercise before the expected time duration, the predetermined duration that is used in determining whether the sensor data includes the predetermined information will be shortened and the reverse applies. 
     In one embodiment, the configurator  214  configures the complexity and/or difficulty of the memory exercise in response of the assessed objective cognitive assessment. If the subject has completed the memory exercise before the expected time duration, the complexity and for difficulty of the memory exercise will be increased and the reverse applies. 
     In one embodiment, the optimizer  212  is coupled to the cognitive function evaluator  206 . The cognitive function evaluator  206  will configure the predetermined information indicative of cognitive functions for remembering in response to the assessed objective assessment. If the subject has completed the memory exercise before the expected time duration, the predetermined information that is used in determining step will be increased and the reverse applies. 
     In one embodiment, the cognitive function evaluator  206  will configure the predetermined duration that is used in determining whether the sensor data includes the predetermined duration in response to the assessed objective assessment. If the subject has completed the memory exercise before the expected time duration, the predetermined duration that is used in determining whether the sensor data includes the predetermined information will be shortened and the reverse applies. 
     In an embodiment, there is a second input  207  from the user via the selection made during the memory exercise. This can be in the form of keyboard, joystick or computer mouse control. 
       FIG. 4  shows that in accordance with the present embodiment, the memory exercise includes flipping and matching cards illustrating pictures and/or words in different languages. Memory of a subject includes immediate memory, visuospatial/constructional memory, attention memory and delayed memory. The actual performance of the memory of the subject is determined by the subject&#39;s speed and the difficulty of the memory exercise. One example is the time duration needed for a subject to flip and match the cards&#39; which utilizes the subject&#39;s cognitive function. Through this memory exercise, the objective cognitive assessment measures the performance of cognitive function for remembering, i.e., memory of the subject. 
     However, those skilled in the art will realize that many other exercises could be used so long as they measure the performance of the memory by addressing two or more of the four components in memory including immediate memory, visuospatial/constructional memory, attention memory and delayed memory. 
     The memory exercise requires the sensor data acquired from the subject to meet predetermined information before the exercise will advance, hence, the subject is required to use the cognitive function for remembering so as to complete the exercise. In the event that the subject is not using the cognitive function for remembering in a manner that is suitable for him/her, the subject will be informed by the indicator. 
     Existing techniques may assume cognitive function and simple indicator of the difficulty like the number of cards in the memory exercise. However, varying cognitive efforts in the same subject and different level of difficulty associated with even the same number of cards will easily render such techniques inaccurate and their results inconsistent from time to time. Therefore, embodiments of the invention seek to solve the problem in the following way. 
     First, it incorporates image processing techniques to automatically analyse the similarity matrix between cards. It then computes a mathematical model of difficulty that combines the similarity measure and the size of the card tiles. Second, the subject&#39;s actual cognitive function for remembering is measured and used to normalize the cognitive workload using an appropriate mathematical model. A robust mathematical model is applied that combines results from multiple test sessions into an objective measurement of memory capacity, which minimizes the effects of irrelevant conditions. 
     Embodiments use the information from the objective cognitive assessment to probabilistically maximize the effect of training. The configurator  214  configures the difficulty measure. In an embodiment where the memory exercise involves matching of pairs of cards having the same pictures, this will be done by optimizing the number of cards and the selection of cards so as to best match the difficulty measure to the subject&#39;s cognitive capacity. 
     For example, the difficulty measure can be controlled such that the subject will be expected to complete it within a given time. The embodiment also adjusts the predetermined information for generating the indicator, such that the subject is able to complete tasks efficiently. 
     The performance index is calculated computationally. Two variables are considered, namely, the difficulty level λ of a computer-based training game (or a computer-based memory exercise, without loss of generality, we use the term training game that also covers the memory exercise), and the minimum of the expectation of time cost τ for completing the game by the subject. 
     Time is also affected by the workload or the cognitive function of the subject during the memory exercise. Therefore, in one embodiment, τ is considered as the theoretical time in which the subject is fully utilizing the cognitive function for remembering. 
       FIG. 5  shows a graphical representation of the change in difficulty level and the time taken. Consider the time τ as a function of the difficulty level λ. Both variables are non-negative. To factor in various difficulty levels, the area under the function curve from 0 is used up to a specified difficulty level, λ 0  
 
 P=∫   0   λ     0   τ(λ) dλ   (1)
 
     The time τ is a monotonic function over λ, since a more difficult game requires a longer time to finish. Mathematically, it says 
     
       
         
           
             
               
                 
                   
                     
                       
                         d 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         τ 
                       
                       
                         d 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         λ 
                       
                     
                     ≥ 
                     0 
                   
                   , 
                   
                     λ 
                     ≥ 
                     0 
                   
                 
               
               
                 
                   ( 
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     A that objectively quantifies the difficulty of a game is measured in the following way. Without loss of generality, the game of remembering is used as an example. Given a layout of a game, there are a few factors that determine the difficulty.
         Number of cards, which can be described by an even number n   Distance between each pair of cards, which can be described by a matrix K;   Similarity between each pair of cards, which can be described by a matrix S;       

     The difficulty is determined by the three variables.
 
λ= f ( K,S,n )  (3)
 
     It should be noted that the three variables are dependent. For example, the size of K and S are essentially determined by n×n The following model describes the function by ignoring K and reducing the information in the matrix S to the mean similarity s between pairs. 
     
       
         
           
             
               
                 
                   λ 
                   = 
                   
                     
                       exp 
                       ⁡ 
                       
                         ( 
                         
                           α 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           
                             
                               s 
                               _ 
                             
                             ⁡ 
                             
                               ( 
                               
                                 
                                   n 
                                   2 
                                 
                                 - 
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                         ) 
                       
                     
                     - 
                     1 
                   
                 
               
               
                 
                   ( 
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       FIG. 6  shows a graphical representation of the change in number of cards and the difficulty level. 
     In the event that a subject plays and finishes memories exercise in time τ 0 , this time is determined by both the subject&#39;s cognitive function ability, as well as the difficulty of the game. With the algorithm decoding information about cognitive functions associated with remembering, the variable of cognitive function is reduced by introducing a normalized time duration in which the subject can finish the session if fully utilizing his/her cognitive function for remembering. 
     
       
         
           
             
               
                 
                   τ 
                   = 
                   
                     
                       
                         τ 
                         0 
                       
                       ⁡ 
                       
                         [ 
                         
                           
                             ∫ 
                             0 
                             τ 
                           
                           ⁢ 
                           
                             
                               ( 
                               
                                 1 
                                 
                                   1 
                                   + 
                                   
                                     e 
                                     
                                       α 
                                       ⁡ 
                                       
                                         ( 
                                         t 
                                         ) 
                                       
                                     
                                   
                                 
                               
                               ) 
                             
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             dt 
                           
                         
                         ] 
                       
                     
                     
                       - 
                       1 
                     
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
     
     The overall memory capacity shall take into account all the possible difficulty level. However, given a number of samples of difficulty-time pairs, it is not straightforward to estimate the area under the function curves till a given upper bound of difficulty level. 
     Therefore, for computing the performance index as in Eq. 1, samples of time and difficulty level are computed above, except the coefficient α in Eq. 4 which requires determination. Estimating the function in Eq. 1 becomes a curve-fitting problem. 
     Since the difficulty level above already accounts for high orders, the relationship between it and the time is expected to be of a low order. Particularly, consider an M-th order polynomial estimation given by Eq. 6:
 
 y=Σ   j=1   M   b   j   x   j   (6)
 
     The zero-order is dropped since y=0 for x=0. 
     For this estimate to be monotonic in the range of [0, ∞], a strong, sufficient condition is
 
 bj≥ 0∀ j   (7)
 
     Therefore, both the coefficients b&#39;s and α need to be determined. In the event that there is a data set of N samples of training game data in terms of triples:  s   i  (reminder: the mean similarity measure of images in the training game), n i  the number of image tiles, and the normalized time duration τ i  for completing the game, it is possible to summarize the above description to formulate the function of τ with respect to the variables 
     
       
         
           
             
               
                 
                   
                     
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                         , 
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                     ⁡ 
                     
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                   = 
                   
                     
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                         j 
                         = 
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                         ⁡ 
                         
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                               exp 
                               ⁡ 
                               
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                   ( 
                   8 
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     Then the optimization problem is formulated as
 
 a,b≥0   max Σ i=0   N (τ a,b )   s     l   ,n   i )−τ i ) 2   (9)
 
     Optimization toolboxes are then utilized to solve the problem. Since the function is highly nonlinear, a globally optimum solution may not be guaranteed. 
     With the estimated coefficients, the performance index, defined by the area under the curve is then given by 
     
       
         
           
             
               
                 
                   P 
                   = 
                   
                     
                       
                         ∫ 
                         0 
                         
                           x 
                           0 
                         
                       
                       ⁢ 
                       
                         
                           ∑ 
                           
                             j 
                             = 
                             1 
                           
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                           ⁢ 
                           
                             x 
                             j 
                           
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                           ⁢ 
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                     = 
                     
                       
                         ∑ 
                         
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                           = 
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                             + 
                             1 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
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                   ) 
                 
               
             
           
         
       
     
     Use of the area under the curve rather than use of the time at a particular difficulty level can provide a more robust estimation of performance, since the latter is more susceptible to noise and also does not account for varying difficulty levels. Besides, this allows prediction of a subject&#39;s overall performance up to an arbitrary difficulty level. 
     In the scenario that the subject undergoing the exercise shall complete a round of memory exercise within a given time at a maximum possible difficulty level, this can be casted as a statistical problem:
 
 P (τ≤τ 0 |λ pl )≤ζ c   (11)
         where t 0  is the given time for the subject to complete the game, ζ C  is a confidence level, e.g., 0.95.       

     For each difficulty level, the time τ can be modelled as a non-negative function described by Eq. 8. 
     Using maximum entropy principle, the variable τ shall be Gamma distributed where the distribution function is determined by two parameters: the scale parameter θ (or its inverse, the rate parameter 
             λ   =     1   Θ           
and the shape parameter k. That is,
 
     
       
         
           
             
               
                 
                   
                     
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             
                               τ 
                               ; 
                               k 
                             
                             , 
                             θ 
                           
                           ) 
                         
                       
                       = 
                       
                         
                           1 
                           
                             θ 
                             k 
                           
                         
                         ⁢ 
                         
                           1 
                           
                             Γ 
                             ⁡ 
                             
                               ( 
                               k 
                               ) 
                             
                           
                         
                         ⁢ 
                         
                           τ 
                           
                             k 
                             - 
                             1 
                           
                         
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                           e 
                           
                             - 
                             
                               y 
                               θ 
                             
                           
                         
                       
                     
                     ; 
                     
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                       ≥ 
                       
                         0 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         and 
                         ⁢ 
                         
                             
                         
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                         k 
                       
                     
                   
                   , 
                   
                     θ 
                     &gt; 
                     0 
                   
                 
               
               
                 
                   ( 
                   12 
                   ) 
                 
               
             
           
         
       
         
         
           
             where Γ( ) is a gamma function given by
 
Γ( k )=∫ 0   ∞   t   k-1   e   −t   dt   (13)
 
           
         
       
    
     Since each difficulty level is associated with a particular random variable for the time τ, the two parameters k and θ are essentially functions of the difficulty level. Practically, we may choose an appropriate k to match the shape of the empirical distribution and then θ is easily determined by both mean and k since  τ =kθ. 
     The cumulative distribution function (CDF) of the gamma function is then 
                     F   ⁡     (       τ   ;   k     ,   θ     )       =       1     Γ   ⁡     (   k   )         ⁢   Y   ⁢     τ   θ               (   14   )               
where γ( ) is the incomplete gamma function.
 
     Then the selection of difficulty level is by solving the following problem
 
max λ( n, s   )subject to  F ( t   0   ; k (λ), θ(λ))≤ζ C   (15)
 
     In a practical system with a finite number of image subsets, every subset and the difficulty level using n and  s  are computed. Then CDFs and the largest one with CDF no larger than ζ C  are calculated. 
     The device and method employ a personalized approach that aims to maximize the training efficiency for each subject. Particularly, this is obtained by using an automated mechanism, called personalized training configuration optimization (PTCO). This mechanism determines the layout of the training program and sets the parameters that best fit to the subject&#39;s conditions in terms of behavioral condition and cognitive condition. The two conditions will be evaluated using the other two unique components: the sensor signal translator using the brain-computer interface technology, and the cognitive assessment engine. 
     The basic scientific principle is that interactions between attention and working memory have been established in neuroscience and psychology. Yet, combining the two through active neuro-physiological computing for more effective cognitive training is a new area, and the feasibility and effects needs to be validated both technically and clinically. 
     The core technology comprises the following.
         A computer-based system for simultaneous training of memory and attention that uses advanced neurocomputing and machine learning techniques;   An objective cognitive (memory) assessment tool that provides information for optimizing training program as well as for cognitive evaluation in clinical use;   An automatic, personalized setting optimization method with probabilistic modelling of difficulty level;   Incorporation of advanced attention detection method that uses physiologic data to evaluate the attention condition in real-time;   New system comprising server-based training system supporting multiple clients       

       FIG. 7  shows a block diagram of the devices  702  ( a )-( e ) in a system  700 . In accordance with the present embodiment, the system  700  has at least one of the devices  702 ( a )-( e ) and a server  704  including a receiver  706 . The receiver  706  is operable to receive the objective cognitive assessment of the subject from the at least one of the devices  702 ( a )-( e ). The system  700  also includes a data storage  708  for receiving and storing the subject profile from the at least one of the devices. The system  700  is also operable to correlate two or more subjects with their respective objective cognitive assessment when it is coupled to two or more of the devices  702  ( a )-( e ). 
     A fifth embodiment provided a computer readable medium for cognitive training. The computer readable medium has stored thereon computer program code which when executed by a computer causes the computer to perform at least the following: obtaining sensor data of a subject during a memory exercise; determining whether the sensor data includes predetermined information indicative of cognitive functions used for remembering; advancing the memory exercise when it is determined that the sensor data includes predetermined information indicative of cognitive functions used for remembering; and calculating an objective cognitive assessment of the subject in response to completion of the memory exercise; wherein cognitive training is measured at least partially in response to the advancing the memory exercise. 
     Experiments and Discussion 
     Participants 
     A total of 38 subjects were assessed for eligibility, among which 3 were excluded for not meeting the criteria. A total of 35 participants were randomized (17 in brain-computer interface (BCI) intervention and 18 in waitlist control). Two participants were found to be ineligible and had been incorrectly randomized; neither received any of the intervention. This left a total of 33 patients in the intention-to-treat (ITT) population, 15 in BCI intervention and 18 in waitlist control. One participant was lost to follow-up after randomization and one other withdrew after completing the week one assessment (both from the waitlist control arm). Neither received any intervention. Therefore, of these 33 in the ITT population, 31 (15 in BCI intervention and 16 in waitlist control) contributed information to the primary efficacy and acceptability analysis. All 31 participants completed all 24 sessions (adherence rate: 100%). 
     Procedure 
     The BCI system used in the present study has been elaborated upon in a previous publication. Before training, all participants underwent a calibration Stroop task. This Stroop task allowed the BCI system to develop an individualized EEG profile representing each participant&#39;s attentive state. 
     Participants in both the intervention and the wait-list group underwent the BCI intervention for 24 sessions over the span of 8 weeks. Each session was planned to take 30-minutes to complete. During each session, participants played a card-pairing memory game, in which they had to focus their attention in order to open or close the cards on screen (see  FIG. 3 ). After each training session, participants were queried as to whether they experienced any adverse events. The intervention group underwent the BCI treatment in their first 8 weeks of being in the trial. The waitlist control arm did not undergo the intervention until after 8 weeks. From Week 9 to 16 the waitlist control arm underwent the same BCI training intervention procedure as the Intervention Arm. All study procedures from the first recruitment to the last follow up was completed between April 2012 and January 2013. 
     Outcome Measures 
     A usability and acceptability questionnaire was administered at each participant&#39;s final BCI training session (week 8 for intervention arm and week 16 for the waitlist control). Participants rated how strongly they agreed with each item on a scale of 1 (Strongly Disagree) to 7 (Strongly Agree). 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Descriptive summary of responses to all items in 
               
               
                 the usability and acceptability questionnaire 
               
            
           
           
               
               
               
               
               
            
               
                 Questionnaire item 
                 Mean 
                 SD 
                 Median 
                 Range 
               
               
                   
               
               
                 Overall I am satisfied with how 
                 6.4 
                 0.8 
                 7 
                 4 to 7 
               
               
                 easy it is to use this device. 
               
               
                 I feel comfortable using this device. 
                 6.4 
                 0.7 
                 6 
                 5 to 7 
               
               
                 I enjoyed playing the game. 
                 6.8 
                 0.5 
                 7 
                 5 to 7 
               
               
                 I think the device is useful in 
                 6.6 
                 0.8 
                 7 
                 4 to 7 
               
               
                 training my memory and attention. 
               
               
                 I will recommend this device to my 
                 6.5 
                 0.8 
                 7 
                 4 to 7 
               
               
                 friends and family. 
               
               
                 Overall I am satisfied with the 
                 6.5 
                 0.6 
                 7 
                 5 to 7 
               
               
                 interface of the game. 
               
               
                 Overall I am satisfied with the 
                 6.5 
                 0.7 
                 7 
                 1 to 7 
               
               
                 whole system. 
               
               
                   
               
            
           
         
       
     
     The efficacy outcome measure was the total score of Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), which was conducted for the intervention arm at Weeks 1, 8 and 16; and the waitlist control arm at Weeks 1, 9 and 16. Adverse or serious adverse events were assessed by querying participants after each session of BCI training if they have experienced any discomfort during the session. A summary of these events, if any, were then collated for each participant at the end of the study. 
     The primary endpoints were: acceptability rate of the BCI device based on participants overall rating scores on a usability questionnaire; and change in total score of the RBANS at week 8 from week 1. Acceptability rate was defined as proportion of participants whose rating score to the whole system was greater than 4 (scale range 1-7). 
     Secondary endpoints included: adherence rate which was defined as the proportion of participants who finished no fewer than 19 BCI sessions (out of 24 offered); changes in the five domain scores of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) at week 8 from week 1, and the change between pre and post BCI sessions for the five domain scores of the RBANS and the total scale index score pooled across groups. 
     Changes in RBANS Scores 
     The median scores of the two arms in the two periods are shown in Table 3. The median difference in the RBANS total scale index score between week 8 and week 1 in the intervention arm pre and post training was 3.0 (range −6 to 28), as shown in Table 2. In the waitlist control arm, the corresponding median of the difference was 2.0 (−18 to 19) during the waitlist period. The waitlist control arm received the BCI intervention between week 9 and 16. The median of the difference in the RBANS total scale index score was 4.5 (−9 to 22) during the intervention period. The corresponding median of the difference between week 8 and week 16 in intervention arm who did not receive treatment during this period was 1.0 (−20 to 29). 
     The Hodges-Lehmann estimate of the median difference in the change scores (from week 1 to week 8) of the total RBANS score between arms was 7.0 (95% CI: −4.0 to 15.0; p=0.332) which was not statistically significant. The point estimate (7.0) reflects an effect size of approximately 0.6 SD. The Hodges-Lehmann estimate of the median differences between arms in the change scores (from week 1 to week 8) of the 5 RBANS domains ranged from 0.5 to 9.5, suggesting an improvement in each of the domains for those participants in the intervention arm. However, none of the differences in change scores across the domain scores were statistically significantly different (Table 2). 
     Pooling the pre and post BCI data from both arms, the median of the changes in total score of the RBANS pre and post BCI was 4.0 (95% CI: −9.0 to 28.0; p&lt;0.001) (Table 3). The median of the changes in immediate memory, visuospatial/constructional, attention and delayed memory domain scores pre and post BCI, both arms pooled, were all statistically significant, except the language domain score. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 A comparison of change in RBANS Domain Index Scores between 
               
               
                 Week 1 and Week 8 for Intervention and Waitlist control arms 
               
            
           
           
               
               
               
               
               
            
               
                 Change in RBANS Scores 
                   
                   
                   
                 Median diff. 
               
               
                 between Week 1 and 8 
                 Intervention 
                 Wait-list 
                 P-value 1   
                 (95% CI) 2   
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Immediate Memory 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Mean (SD) 
                 8.3 
                 (18.4) 
                 −1.8 
                 (17.2) 
               
               
                 Median (range) 
                 6.0 
                 (−17 to 44) 
                 −3.0 
                 (−33 to 40) 
                 0.160 
                 9.5 
                 (−3.0, 25.0) 
               
               
                 Visuospatial/Constructional 
               
               
                 Mean (SD) 
                 4.1 
                 (12.3) 
                 3.5 
                 (15.4) 
               
               
                 Median (range) 
                 4.0 
                 (−13 to 32) 
                 1.5 
                 (−21 to 37) 
                 0.782 
                 2 
                 (−10.0, 12.0) 
               
               
                 Language 
               
               
                 Mean (SD) 
                 0.1 
                 (21.6) 
                 −1.4 
                 (20.7) 
               
               
                 Median (range) 
                 −4.0 
                 (−30 to 42) 
                 0.0 
                 (−36 to 38) 
                 0.937 
                 0.5 
                 (−15.0, 17.0) 
               
               
                 Attention 
               
               
                 Mean (SD) 
                 4.1 
                 (12.2) 
                 3.0 
                 (13.5) 
               
               
                 Median (range) 
                 6.0 
                 (−27 to 25) 
                 1.5 
                 (−29 to 31) 
                 0.677 
                 1 
                 (−6.0, 10.0) 
               
               
                 Delayed Memory 
               
               
                 Mean (SD) 
                 6.5 
                 (11.2) 
                 2.1 
                 (11.3) 
               
               
                 Median (range) 
                 4.0 
                 (−7 to 37) 
                 0.0 
                 (−24 to 22) 
                 0.362 
                 2.5 
                 (−4.0, 11.0) 
               
               
                 RBANS Total Scale Index Score 
               
               
                 Mean (SD) 
                 7.6 
                 (11.4) 
                 1.2 
                 (11.3) 
               
               
                 Median (range) 
                 3.00 
                 (−6 to 28) 
                 2.0 
                 (−18 to 19) 
                 0.332 
                 7 
                 (−4.0, 15.0) 
               
               
                   
               
               
                   1 P-value from the Mann-Whitney U test 
               
               
                   2 Hodges-Lehmann estimation and its associated 95% confidence interval 
               
            
           
         
       
     
                     TABLE 3                  Changes of RBANS individual index sub-scores and total       scale index score pre and post intervention, pooling data       from both Intervention and Waitlist control arms.                                 Change in RBANS scores                   pre and post-treatment   Summary statistics   P-value 1                               RBANS Domain Index Scores                                     Immediate Memory                       Mean (SD)   6.9   (17.6)           Median (range)   6.0   (−28 to 44)   0.038           Visuospatial/Constructional           Mean (SD)   5.2   (11.2)           Median (range)   4.0   (−13 to 32)   0.014           Language           Mean (SD)   2.4   (16.8)           Median (range)   0.0   (−30 to 42)   0.547           Attention           Mean (SD)   3.4   (11.0)           Median (range)   6.0   (−27 to 25)   0.039           Delayed Memory           Mean (SD)   6.1   (10.0)           Median (range)   6.0   (−12 to 37)   &lt;0.001                         1 P-value from the Wilcoxon signed rank test            
Safety
 
     There were no adverse or serious adverse events reported during the study period by any of the participants. 
     Discussion 
     As seen from the responses for the usability and acceptability questionnaire, feedback from participants was positive. The very high adherence rate also suggested a high level of motivation among the participants. These factors indicated that elderly users may be sufficiently motivated to adhere to the training program even in their own homes. 
     RBANS total scores improved by a similar magnitude pre and post training, and this occurred for both intervention and waitlist control arms (between Week 1 and 8 for intervention, and Week 9 and 16 for waitlist control). The RBANS total scores did not change in the waitlist control arm before the intervention. In addition, between Weeks 9 and 16 when the intervention arm ceased treatment, their mean RBANS total score neither decreased to baseline level nor improved at an equally large magnitude as between weeks 1 and 8. The time sequence of the changes can be taken as support that improvements in mean RBANS total scores between weeks 1 and 8 for the intervention arm were due to the BCI treatment effect. 
     While the data indicated that the intervention arm showed a larger improvement in RBANS total scores between Weeks 1 and 8 as compared to the waitlist control arm, this difference did not reach statistical significance. Thus, the study does not provide conclusive evidence for a difference in attention and memory in the normal elderly as assessed by the total score on the RBANS between intervention arm and waitlist control. Nevertheless, an effect size of 0.6 SD was obtained. This decision is also supported by the highly significant result obtained when data from both arms were pooled, showing a positive shift in RBANS total scores pre and post-BCI training. 
     It is notable that, pooling both arms, the scores for all five RBANS domains showed statistically significant positive changes pre and post BCI, except for language. This differentiated improvement suggests that gains in RBANS scores are valid indications of the efficacy of the training program, which targets attention and memory but not language. The significantly positive change in Visuospatial/Constructional could be attributed to the visual and pictorial nature of the memory task. This may have honed the participants&#39; attentiveness to pictorial stimuli, which are used to assess the Visuospatial/Constructional domain in RBANS. In addition, while the nature and modality of tasks used in training and assessment were very different (e.g. visual memory of pictures vs auditory memory of word lists), putative improvements in memory and attention during training were translated to score increases in both the relevant domain and global scores for RBANS. This could be taken as further evidence that the training results in global rather than task-specific improvements in cognitive functioning. 
     While several exemplary embodiments have been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist, including variations as to the information that is used as input and how the memory exercise is carried out. 
     It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.