Abstract:
A kit and method for determining whether an individual has Attention Deficit Hyperactivity Disorder, comprising a device for sampling the peripheral skin temperature of a human subject during a predetermined time interval when the subject is in an inactive state, and an analyzer for analyzing the sampled peripheral skin temperature data for a pre-selected parameter, to determine whether the pre-selected parameter has a value indicative of ADHD.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation of the earlier filing date of U.S. patent application Ser. No. 09/597,610, filed Jun. 20, 2000. 
    
    
     FIELD OF THE INVENTION 
     This invention relates in general to a technique for diagnosing Attention Deficit Hyperactivity Disorder (ADHD) and more particularly to a home kit technique for measuring an individual&#39;s peripheral temperature to determine values indicative of ADHD. 
     BACKGROUND OF THE INVENTION 
     ADHD is the most common neurobehavioral disorder of childhood as well as among the most prevalent health conditions affecting school-aged children. Between 4% and 12% of school age children (several millions) are affected. $3 billion is spent annually on behalf of students with ADHD. Moreover, in the general population, 9.2% of males and 2.9% of females are found to have behavior consistent with ADHD. Upwards of 10 million adults may be affected. 
     ADHD is a difficult disorder to diagnose. The core symptoms of ADHD in children include inattention, hyperactivity, and impulsivity. ADHD children may experience significant functional problems, such as school difficulties, academic underachievement, poor relationships with family and peers, and low self-esteem. Adults with ADHD often have a history of losing jobs, impulsive actions, substance abuse, and broken marriages. ADHD often goes undiagnosed if not caught at an early age and affects many adults who may not be aware of the condition. ADHD has many look-alike causes (family situations, motivations) and co-morbid conditions (depression, anxiety, learning disabilities). 
     Diagnosis of ADHD involves a process of elimination using written and verbal tests. However, there is no one objective, independent valid test for ADHD. Various objective techniques have been proposed but have not yet attained acceptance. These include: 
     1. The eye problem called convergence insufficiency was found to be three times more common in children with ADHD than in other children by University of California, San Diego researchers. 
     2. Infrared tracking to measure difficult-to-detect movements of children during attention tests combined with functional MRI imaging of the brain were used by psychiatrists at McLean Hospital in Belmont, Mass. to diagnose ADHD in a small group of children ( Nature Medicine , Vol. 6, No. 4, April 2000, Pages 470-473). 
     3. Techniques based on EEG biofeedback for the diagnoses and treatment of ADHD are described by Lubar ( Biofeedback and Self-Regulation , Vol. 16, No. 3, 1991, Pages 201-225). 
     4. U.S. Pat. No. 5,913,310, issued Jun. 22, 1999, inventor Brown, discloses a video game for the diagnosis and treatment of ADHD. 
     5. U.S. Pat. No. 5,377,100, issued Dec. 27, 1994, inventors Pope et al., discloses a method of using a video game coupled with brain wave detection to treat patients with ADHD. 
     6. Dr. Albert Rizzo of the Integrated Media Systems Center of the University of Southern California has used Virtual Reality techniques for the detection and treatment of ADHD. 
     Although skin temperature spectral characteristics have been shown to indicate stress-related changes of peripheral vasomotor activity in normal subjects, there has been no disclosure of use of variations in skin-temperature response to assist in diagnosing ADHD. (See:  Biofeedback and Self-Regulation , Vol. 20, No. 4, 1995). 
     As discussed above, the primary method for diagnosing ADD is the use of a bank of written and verbal tests designed to assess criteria established by American Medical Association (AMA) as described in the Diagnostic and Statistics manual-IV (DSM-IV) and administered by the school psychologist or other licensed practitioner. In some cases those individuals who meet DSM-IV criteria for ADHD diagnosis are prescribed a drug such as Ritalin. Behavioral observations of the patient while on Ritalin are conducted to assess the imact of prescribed medication. U.S. patent application (Ser. No. 09/597,610) describes an apparatus and method of determining whether an individual has Attention Deficit Disorder. In none of the prior art is there disclosed a method for screening for ADHD at home using a home kit. 
     There is thus a need for a simple, inexpensive, and reliable technique for determining whether an individual has Attention Deficit Hyperactivity Disorder (ADHD) in the home. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a solution to the problems and fulfillment of the needs discussed above. 
     According to a feature of the present invention, there is provided a kit for determining whether an individual has Attention Deficit Hyperactivity Disorder (ADHD) comprising: 
     a device for sampling the peripheral skin temperature of a human subject during a predetermined time interval when the subject is in an inactive state; and 
     an analyzer for analyzing the sampled peripheral skin temperature data for a pre-selected parameter, to determine whether said pre-selected parameter has a value indicative of ADHD. 
     ADVANTAGEOUS EFFECT OF THE INVENTION 
     The invention has the following advantages. 
     1. A device and technique for diagnosing ADHD is provided which is simple, inexpensive and reliable and usable in the home in the form of a kit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic view illustrating use of an embodiment of the present invention. 
     FIG. 2 is a perspective view showing in greater detail the embodiment of FIG.  1 . 
     FIG. 3 is a block diagram of a system incorporating the present invention. 
     FIG. 4 is a block diagram of a modification of the system of FIG.  3 . 
     FIGS. 5 and 6 are graphical views useful in explaining the present invention. 
     FIG. 7 is a diagrammatic view useful in explaining the present invention. 
     FIG. 8 is a diagrammatic view useful in explaining the present invention. 
     FIG. 9 is a diagrammatic view of another embodiment of the present invention. 
     FIG. 10 is a diagrammatic view of another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to the invention, it has been found that a signature of ADHD is hidden in fluctuation of the temperature of the skin as measured at the extremities such as at a fingertip. Biofeedback practitioners have long used measurement of hand temperature to help subjects manage their physiology by controlling blood flow to the extremities. The literature reports that reduced blood flow to the brain is frequently found in patients with ADHD. 
     As shown in FIG. 1, a subject  10  is sitting on a chair  12  at a table  13  watching a screen  14 . The screen  14  is used to block any visual stimulus from disturbing the subject  10 . The subject  10  is wearing a set of earphones  20 . The earphones  20  can be connected to a sound-generating device not shown. The earphones  20  can be used to block out ambient noise or to produce a white noise intended to reduce or eliminate the audio stimulus from the environment during the test. The subject is at rest in an inactive state. The fingertip  16  of subject  10  is inserted into an analyzer module  18 , where the skin temperature is measured via a sensor  22  (shown in FIG.  2 ). 
     Analyzer module  18  includes a temperature sensor  22 , where the subject  10  inserts their fingertip  16  in groove  17 , an on/off switch  24 , and a display  26 . The analyzer module  18  can have an internal power supply, such as a battery  30 , or an external low voltage power supply port  32  for an external low voltage power supply (not shown), such as used for a telephone. The analyzer module  18  can be connected to an external CPU  44  (shown in FIG. 10) via a cable  27  (such as an USB or RS 232 cable), or wireless transmitting device such as an RF or IR link (not shown). In a further embodiment a second temperature sensor module  28  can be connected to the analyzer  18  via a cable  29 . The second temperature sensor module  28  can be used to sample the skin temperature of the subject&#39;s  10  other hand and includes groove  50  and temperature sensor  52 . 
     Referring now to FIG. 3, analyzer module  18  includes analyzer circuit  100  including temperature sensor  102 , temperature sampling, amplifier and signal conditioner circuit  104 , analog to digital converter  106 , digital signal analysis  108 , LCD (fluid crystal display) display  110 , battery  112 , power switch  114  and power conversion and/or regulation  116 . 
     FIG. 4 shows a modification of the circuit  100  of FIG.  3  and includes a slot  118  for receiving a memory media  119  (such as a memory card, floppy disk, etc.) which can provide system upgradability and removable data export without compromising safety isolation. 
     Referring again to FIG. 1, the fingertip temperature is first recorded during an interval when the subject  10  has been asked to sit quietly for a given period of time, nominally about  10  minutes. The time period may be shorter or longer. The temperature data is sampled via circuit  104  (shown in FIG. 3) at a time interval Δt creating a list of N temperature samples, which are digitized by A/D converter  106  and which are stored in memory (not shown). The N samples are divided into windows of m samples. The data from each window is then passed through a Fast Fourier Transform (FFT) algorithm in data signal analysis circuit  108  producing 2 m−1  data points spaced equally in frequency space. The values are complex numbers having form 
      FFT( f   n )= A ( f   n )+ B ( f   n ) i   
     where i is the {square root over (−1)}. The Phase Φ(ƒ n ) can be found from the equation                Φ        (     f   n     )       =       Tan     -   1            (       B        (     f   n     )         A        (     f   n     )         )               (   .00   )                                
     and the Magnitude M(f n ) from                M        (     f   n     )       =           B        (     f   n     )       2     +       A        (     f   n     )       2                 (   0.0   )                                
     FIG. 5 graphically illustrates the temperature signal during one window for a normal subject and a person diagnosed with ADHD. FIG. 6 graphically illustrates the magnitude transform for the data corresponding with a subject with ADHD and a normal subject. The magnitude spectrum undergoes dramatic changes essentially changing from a hyperbolic curve to a flat response. These graphical illustrations as well as the following can be displayed on display  110  or on some other visual indication device. 
     The following is another feature of the present invention: 
     Raw Data 
     The raw data T i,k (t) is the temperature taken at a fingertip during the baseline period. 
     Windows 
     The data for each session were divided into a series of windows prior to performing the Fourier Transform operation. Call the window width w. For each window a FFT algorithm calculates the Fourier Transform F(f). The Magnitude and Phase of this transform are defined as given above. The range of magnitude variation during a window is given below where f max  and f min  are the frequencies where the Magnitude is the greatest and the least respectively (note the dc component at frequency zero is excluded). 
     
       
           M   range   =[M ( f   max   −M ( f   min ] 
       
     
     Session Mean and Standard Deviation 
     The mean magnitude range for subject i during session k is found from equation 1.0. where m is the number of windows in the session.                〈     M     i   ,   k       〉     =         ∑     j   =   1     m                     [         M        (     f   max     )       j     -       M        (     f   min     )       j       ]       m             (   1.0   )                                
     And the corresponding standard deviation is:                〈     s     i   ,   k       〉     =           ∑     j   =   1     m                       {       [         M        (     f   max     )       j     -       M        (     f   min     )       j       ]     -     〈     M     i   ,   k       〉       }     2         m   -   1                 (   1.1   )                                
     Determination Indicator 
     Positive diagnostic indicator is established based upon the chart of FIG. 7 by setting a threshold level (e.g.,  3 ) for one of the parameters. Below that limit, the subject has a positive diagnostic indicator for ADHD. Above the limit, the subject has a negative diagnostic indicator for ADHD. This procedure can be improved by taking peripheral temperatures during different times of the day over a period of one or more days. FIG. 8 shows the results taken at different times of the day over a period of two days. 
     FIG. 9 is a diagrammatic view of the subject  10  and the analyzer  18  in another embodiment of the present invention. Shown is the subject  10 , wearing a pair of translucent glasses or goggles  40 . The glasses or goggles  40  are used to block any visual stimulus from the subject  10 . An eye mask can also be used. 
     A further embodiment of the present invention is shown in FIG.  10 . The analyzer  18  is connected via a cable  27  to a computer  44 . As in FIGS. 1 and 2 like numerals indicate like parts and operation. The subject&#39;s  10  skin temperature response as described above is sampled via the analyzer  18  connected via the cable  27  to the CPU  44 . CPU  44  applies the appropriate transforms to analyze the sampled temperatures and displays the results on the monitor  46 . The results from the test can be stored in the CPU&#39;s memory (not shown) and can be transmitted via a transmission link such as the Internet to other locations. Alternatively the signals from analyzer can be transmitted by wired (telephone) or wireless (cell phone) communication to a remote location where the data is analyzed and transmitted back to analyzer  18  for display. 
     The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
     PARTS LIST 
       10  human subject 
       12  chair 
       13  table 
       14  screen 
       16  fingertip 
       17  digit groove 
       18  analyzer module 
       20  ear phones 
       22  sensor 
       24  on/off switch 
       26  display 
       27  cable 
       28  sensor module 
       29  cable 
       30  battery 
       32  external low voltage power supply port 
       40  goggles/glasses 
       44  computer (CPU) 
       100  analyzer circuit 
       102  sensor 
       104  signal conditioner 
       106  analog to digital converter 
       108  digital signal analysis 
       110  LCD display 
       112  battery 
       114  power switch 
       116  power conversion and/or regulation 
       118  memory card slot