Abstract:
The system of the present invention is intended to provide a simple, out-of-clinic sleep disorders testing tool. It can be used for pretest screening and diagnosis, and post therapy follow-up of patients. The hardware component comprises a disposable sensor pack containing a PVDF airflow sensor and a PVDF pulse wave sensor, each of which is permanently connected to a signal conditioning and communications module configured to communicate with a patient&#39;s smartphone via a Bluetooth circuit. An APP stored in the smartphone allows a patient to initiate a diagnostic recording, collect and store digitized data onto the phone and, subsequently, upload data to a secure server for analysis on a host computer following completion of the test.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
       [0001]    The present application relates somewhat to application Ser. No. 14/744,426, filed Jun. 19, 2015 and entitled “METHOD FOR DETECTING AROUSALS IN SLEEPING SUBJECTS” and application Ser. No. 14/683,509, filed Apr. 10, 2015, and entitled “SCREENING SYSTEM FOR ASSESSING SLEEP ABNORMALITIES”. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    I. Field of the Invention 
         [0004]    This invention relates generally to an apparatus and method for conducting a home diagnostic testing and screening for sleep related disturbances and, more particularly, to a system that utilizes a patient&#39;s own smartphone as a data acquisition and data transfer device. 
         [0005]    II. Discussion of the Prior Art 
         [0006]    Obstructive sleep apnea is the most common sleep disorder and is responsible for more mortality and morbidity than any other sleep disorder. Sleep apnea is characterized by recurrent failures to breath adequately during sleep, primarily due to obstructions in the upper airway. 
         [0007]    Apnea is defined as a complete cessation of airflow. A related sleep disorder, termed hypopnea, is defined as a reduction in airflow disproportionate to the amount of respiratory effort expended and insufficient to meet the individual&#39;s metabolic needs. During episodes of apnea or hypopnea, oxygen levels in the brain decrease while the carbon dioxide level rises. This causes the sleeper to awaken. The brief arousals to breath are followed by a return to sleep. 
         [0008]    Obstructive sleep apnea is a serious, yet treatable, health problem worldwide. Published reports indicate that untreated obstructive sleep apnea patients are three to five times more likely to be involved in industrial and motor vehicle accidents and have impaired vigilance and memory. Untreated apnea leads to hypertension, stroke, heart failure, heart attacks and other maladies. 
         [0009]    The current standard for the diagnosis of obstructive sleep apnea is a relatively expensive overnight sleep study in a hospital or clinic. Here, a variety of physiologic sensors typically involving electroencephalograms, respiratory airflow, respiratory effort, oxygen saturation, snore sounds and body position are fed into an instrument called a polysomnograph (PSG). 
         [0010]    Because of the relative expense involved in having the aforementioned type of sleep study conducted, a need exists for a lower cost way to determine whether a PSG sleep study is needed. As a result, several portable sleep monitors have been developed that can be used in a patient&#39;s own home as a screening tool. 
         [0011]    While home sleep screening protocols measure significantly fewer physiologic parameters than are typically involved in a PSG-based study, the results of home screening tests that measure respiratory airflow and respiratory effort provide enough information to determine whether a person is a candidate for a comprehensive sleep study or whether there is an immediate need for the patient to acquire and begin use of a CPAP device. 
         [0012]    Many industries find it essential that their workers be alert during the execution of their job performance. For example, airline crews, over-the-road truckers and hospital personnel and all those who have the safety of the public as a responsibility should be periodically screened for sleep abnormalities. The expensive testing of thousands of employees in PSG-based sleep labs could prove prohibitively expensive while the cost of running a home sleep screening and diagnostic test can be made sufficiently inexpensive that it can be used to sort out only those employees who test positive for disturbed sleep patterns. Such persons would be encouraged or required to undergo a full sleep study possibly as a condition of continued employment. The present invention provides such a low cost screening and diagnostic testing system for at-home use, one that uses a subject&#39;s own smartphone as a data acquisition and data transfer device. Thus, the apparatus of the present invention is intended to test patients for a variety of sleep abnormalities. The outcome of the testing procedure is acceptable as a preliminary risk assessment tool as well as a diagnostic tool for sleep disordered breathing, sleep disruption and in some cases sufficient for prescriptions for therapy. 
         [0013]    Users of the present invention may typically be a testing service provider or a business corporation that has a need to make sure that its employees are not compromised due to disturbed sleeping. The patient or employee will apply the sensors and follow the test procedure instructions provided via the subject&#39;s own cell phone. Once the digitized sensor data is collected over a predetermined test interval, it will be sent via the cell phone to the host computer where a data analysis program will analyze the data and generate a report. 
       SUMMARY OF THE INVENTION 
       [0014]    In accordance with the present invention, the method for conducting home testing of patients for sleep related disturbances involves first having a testing service firm provide the patient with a sensor kit that includes as its components (i) a first polyvinylidene fluoride (PVDF) sensor adapted to be placed on a patient&#39;s upper lip for sensing thermal changes due to breathing and episodes of snoring, (ii) a second PVDF sensor adapted for placement on a patient&#39;s finger for sensing pulse wave amplitude, and (iii) a sensor module to which the first and second PVDF sensors are electrically connected. The sensor module includes amplifiers and filters for generating separate wave forms relating to respiration, snoring and pulse wave amplitude variation. The sensor module further includes an analog to digital converter for transforming the analog wave forms into a digital representation thereof for entry into the memory of a microprocessor also forming a part of the sensor module. It, in turn, controls the transmission of data, via a wireless Bluetooth link, to a patient&#39;s smartphone. 
         [0015]    An application program (APP), which the patient downloads from a host computer of a testing service provider, is stored on the smartphone. It functions to display a sleep test set-up procedure and operating instructions to the patient for display on his or her smartphone screen. 
         [0016]    Following set-up in accordance with the displayed set-up instructions, the patient is instructed to activate a “start” button on the smartphone and, while subsequently sleeping, the information transmitted to the smartphone from the sensor module is captured and stored in the memory of the smartphone during a test period of a predetermined length. At the conclusion of the test period, the patient is coached to actuate an “upload” icon on the smartphone display screen resulting in the contents of the smartphone memory being sent over the internet to a host computer at the testing service provider&#39;s facility where that digitized wave form information is analyzed resulting in the generation of a test report. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0017]    The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views referred to corresponding parts. 
           [0018]      FIG. 1  is a hardware block diagram of a low-cost, disposable sensor kit applied to a patient and capable of transmitting sensor data to the patient&#39;s own cell phone; 
           [0019]      FIG. 2  is a schematic block diagram of the disposable sensor module employed; 
           [0020]      FIG. 3  is a software flow diagram of an application program that may be downloaded from a host computer of a sleep testing service provider (STSP) for installation on a patient&#39;s cell phone for setting up the apparatus of  FIG. 1  in preparation for an ensuing screening; 
           [0021]      FIG. 4  is a software flow diagram and part of the application (APP) installed on the patient&#39;s smartphone for collecting and storing data from the disposable sensor pack of  FIG. 1 ; and 
           [0022]      FIG. 5  illustrates the steps of the APP for uploading data from the patient&#39;s cell phone to a host computer at the STSP. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring to  FIG. 1 , there is illustrated the hardware components comprising the present invention. It comprises a disposable sensor kit shown enclosed by the broken line box  10  and includes an airflow sensor  12 , a pulse wave amplitude sensor  14  and an electronic sensor module  16 . The sensor kits are made available either directly or through an employer by the STSP and are sufficiently inexpensive that they can be disposed of after a single use. 
         [0024]    As will be explained in greater detail below, the sensor module  16  is able to communicate over a Bluetooth link to a smartphone  18  which, in turn, is capable of communicating over the internet to a host computer  20 , typically located at a sleep testing service provider&#39;s location. 
         [0025]    The airflow sensor is preferably of a type described in the Stasz U.S. Pat. No. 7,608,047 assigned to the Dymedix Corporation of Shoreview, Minn., and is designed to be worn on a patient&#39;s upper lip where it is exposed to respiratory airflow and vibration occasioned by episodes of snoring. The sensor  12  incorporates a polyvinylidene fluoride (PVDF) pyro/piezoelectric transducer and is connected by leads  22  to the sensor module  16 . 
         [0026]    The pulse wave amplitude sensor  14  also incorporates a PVDF film transducer and is configured to be adhesively affixed to a patient&#39;s finger where it responds to the patient&#39;s pulse wave resulting from the beating action of his or her heart. The pulse wave amplitude transducer  14  is more particularly described in applicants&#39; currently pending application Ser. No. 14/744,426, filed Jun. 19, 2015, and which is hereby incorporated by reference. 
         [0027]      FIG. 2  is a block diagram of the circuitry embodied in the sensor module  16 . The sensor module is a low power, microprocessor control, data acquisition module that filters, preprocesses, and transmits digitized PVDF airflow, snore and pulse wave sensor data to the smartphone. The data is digitally transferred from the sensor module to the receiving smartphone via low power Bluetooth protocol which, in turn, is transmitted by the smartphone  18  via 3g or other communications to a host computer for data analysis and report generation. An input signal from the airflow sensor  12  is first amplified by an amplifier circuit  26  and then applied to a filter network  28  capable of separating the pyro signal of the airflow sensor  12  from the piezo signal from the sensor  12  due to episodes of snoring. It is the temperature variations due to inspiratory and expiratory airflow from the nose and mouth of the patient that produces the pyro signal on output line  30  and the signal due to snoring on the output line  32 . Those interested in details of the filter arrangement that can be employed are referred to the Stasz U.S. Pat. No. 6,702,755. 
         [0028]    The input from the pulse wave amplitude sensor is applied to an amplifier  34  and a filter network  36  with the resulting output appearing on line  38 . The output lines  30 ,  32  and  38  are applied to an analog-to-digital converter  40 , preferably a Texas Instruments TLC2543C integrated circuit. It comprises a 12-bit analog-to-digital converter, a 14-channel multiplexer and microprocessor-compatible control logic. Its 14-channel multiplexer with address logic is capable of directly accessing any of 14 single-ended, analog signals. The A/D converter  40  has a tri-state output latch buffer that provides its output to a microprocessor  42  that has been programmed to store and buffer digital output signals representative of the sensed airflow, the snore and pulse wave amplitude inputs. The microprocessor  42  is preferably equipped with a built-in Bluetooth radio, but in  FIG. 2 , a Bluetooth adaptor  44  is shown separately. 
         [0029]    As those skilled in the art know, Bluetooth is a short-link radio technology device used to create a wireless connection to a smartphone, as indicated in  FIG. 1 . 
         [0030]    With continued reference to  FIG. 1 , the smartphone  18  may be of a type having the Android operating system or the iPhone operating system commonly referred to as iOS and developed by Apple, Inc. In the case of both the Android operating system and the iOS, the user interface is based on the concept of direct manipulation on a touch screen. Interface control elements consist of sliders, switches and buttons in which gestures such as swipe, tap, pinch and reverse pinch may be used to interact with the device. For purposes of illustration only, in  FIG. 1 , the smartphone  18  is illustrated as displaying a pulse wave signal  46 , an airflow signal  48  and a snore signal  50  on its touch screen. The area on the display labeled  52  may be used to present a signal strength indicator while button areas  54  and  56  may be start and stop switches. The window  58  may be used to present status information while window area  60  may present hours and minutes of a test&#39;s duration. Switch  62  may be used to initiate the uploading of data from the smartphone to a remote host computer  20  via the internet. 
         [0031]    Available for download from the STSP is an application firmware program commonly referred to as an APP offering the following functionality:
       Provide pairing connectivity with the sensor module  16  via the Bluetooth link.   Start/Stop recording via switches  54  and  56 .   Record transmitted data from sensor module  16  for a predetermined test time, e.g., 10 hours.   Provide fault instructions to patient and the STSP.   Record non-sensor environmental noise via the microphone of the smartphone and video with audio from the phone camera.       
 
         [0037]    It is further contemplated that software releases will be easily configurable by the STSP to specify varying upload server locations and test sponsoring company names prior to being made available to end user patients. 
         [0038]    The APP also provides easy to understand, step-by-step “Wizard” user interface that walks the patient through each step of the test procedure.  FIG. 3  is a software flow diagram of the set-up Wizard forming part of the APP that the patient is instructed to download onto his or her smartphone. 
         [0039]    Following a start operation, an initial check of the phone is performed to insure adequate disk space for data storage (Block  64 ). A test is then made at decision block  66  and, if storage space is insufficient, the setup terminates. If, however, the check determines that the storage space is sufficient, a check is made to see if the smartphone is coupled to an external power source, recognizing that the test may take place over a prolonged period, which would deplete the battery of the smartphone if an external charger was not attached (Block  68  and decision Block  70 ). At operation block  72 , the user is instructed to input an ID, along with demographic and contact information, including email address for return of test results. 
         [0040]    Next, at operation block  74  and decision block  76 , the patient must provide authorization to release medical information as required by the Federal Health Information Portability and Privacy Act. Provided authorization is granted, and as indicated by block  78  in  FIG. 3 , the patient is coached by instructions for turning on the sensor module  16  and a check is made of the sensor signal quality to insure correct placement of the sensors  12  and  14  and the continuity of the leads  22  and  24 . 
         [0041]    The test at decision block  80  indicates that telemetry is established. Next, the patient is provided with text material on the smartphone screen on how to attach the sensors  12  and  14  (Block  82 ). Once the sensors are attached, the software tests the sensor signal quality at block  84  and, if the signal quality is poor, as determined at decision block  86 , the patient is provided with further instructions on how to reposition the sensor to improve sensor quality (Block  88 ). 
         [0042]    Assuming that the sensor signal quality meets predetermined criteria, the patient is instructed to take a video recording of himself or herself, as indicated by operation blocks  90  and  92 . This requires the patient to look into the smartphone screen, press the record button and recite a short sentence that is provided to them on the screen, stating their name, current date and time, and stating that they are in fact the person who will be using the device, thus, establishing and documenting a chain of custody. 
         [0043]    Referring next to  FIG. 4 , it shows the steps involved in the data acquisition stage of the APP. As seen at operation block  94 , the signal strength is indicated on the smartphone  18  in the field  52  and the status is displayed in the field  58 . For example, the status may be “standby”, “recording”, “off”, or “no Bluetooth”. Touching the “start” button  54  initiates recording of the wave form data  46 ,  48  and  50  in a RAM memory of the microprocessor  42  in the sensor module  16 . See Block  98 . This digitized wave form data is then transferred over the Bluetooth link to the smartphone (Block  100 ). It is stored in the memory of the smartphone (Block  102 ). 
         [0044]    During the test interval, a check is periodically made to assure that the data acquisition on the smartphone is not lost. See decision Block  104 . If the test at block  104  indicates that data acquisition is lost, the cell phone is made to beep to awake the patient and instructions are provided on how to reposition the sensor to restore data acquisition (Block  106 ). If data acquisition is not lost, a test is made at decision block  108  on whether 10 hours of sleep data has been acquired. If not, the operation loops back to block  98  where further data is collected. However, if there has been 10 hours of data acquisition, an audible signal is again issued by smartphone and instructions are provided to the patient to press the “stop” button. See Blocks  110  and  112 . 
         [0045]    The flowchart of  FIG. 5  illustrates the operations embodied in the APP downloaded by the smartphone for transferring the collected test data to the remote host computer  20  at the sleep test service provider&#39;s facility. At the conclusion of the collection of, for example, 10 hours of sleep test data, a message is provided on the screen of the smartphone for initiating the upload of the data from the smartphone to the remote host computer. Actuation of the upload button (Block  114 ) establishes a communication protocol between the smartphone and the host computer via the internet. Data, including the recorded wave forms, the demographic information provided by the subject and the audio and video subject identification and verification information is thus uploaded from the smartphone to the host computer (Block  116 ) while a display meter on the smartphone shows the upload progress (Block  118 ). Once the data transfer from the smartphone to the host computer is completed, a further message is provided on the smartphone screen providing the patient with instructions on how the data acquisition module  10  is to be disposed of (Block  120 ). Lastly, a “test completion” message is provided to the patient via the smartphone and contact information of the test provider is presented (Block  122 ). 
         [0046]    The software program executed by the host computer  20  at the testing service provider&#39;s facility for analyzing the received wave forms and producing a study report is more particularly described in co-pending application Ser. No. 14/683,509, filed Apr. 10, 2015, the contents of which are hereby incorporated by reference. 
         [0047]    This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices. Also, various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.