Systems and methods to assess balance

Abstract

This disclosure relates to a system and method to analyze balance and stability of a patient. Test data for the patient, representing motion of a device affixed to the patient during a test interval, can be received. The test data can be processed to provide processed data (or sensor-derived data) that includes at least one of acceleration data, rotational rate data and rotational position data for the test interval. A biomechanical model can be applied to the processed data to provide center of mass (COM) motion data representing movement of the COM in multiple dimensions for the patient during the test interval. An indication of balance for the patient can be determined based on the COM motion data. The indication of balance can be used to analyze the balance and stability of the patient.

What is claimed is: 
     
         1 . A computer implemented method, comprising:
 receiving test data for a patient that represents motion of a portable device affixed to the patient during a test interval;   processing the test data to provide processed data that includes at least one of acceleration data, rotational rate data and rotational position data for the test interval;   applying a biomechanical model to the processed data to provide center of mass (COM) motion data representing movement of the COM in multiple dimensions for the patient during the test interval; and   determining an indication of balance for the patient based on the COM motion data.   
     
     
         2 . The method of  claim 1 , wherein the portable device comprises one or more sensors and is attached to a patient proximal the COM of the patient. 
     
     
         3 . The method of  claim 2 , wherein the portable device comprises sensors that record the test data. 
     
     
         4 . The method of  claim 3 , wherein the sensors comprise an accelerometer and a gyrometer, and
 wherein the test data comprises accelerometer data and gyrometer data.   
     
     
         5 . The method of  claim 4 , wherein the processing the test data further comprises:
 interpolating the accelerometer data;   filtering the interpolated acceleration data;   applying an offset function to the filtered accelerometer data and the interpolated accelerometer data to provide acceleration data;   interpolating the gyrometer data;   filtering the interpolated gyrometer data to provide rotation rate data; and   integrating the rotation rate data to provide rotational position data.   
     
     
         6 . The method of  claim 1 , wherein the determining the indication of balance for the patient further comprises computing area data based on the COM motion data,
 wherein the area data corresponds to a two-dimensional projection of a spatial path traveled by the COM of the patient.   
     
     
         7 . The method of  claim 6 , wherein the computing the area data further comprises computing the areas in at least two orthogonal planes. 
     
     
         8 . The method of  claim 7 , wherein the determining the indication of balance for the patient further comprises computing volume data based on the areas computed in the at least two orthogonal planes. 
     
     
         9 . The method of  claim 1 , further comprising analyzing the balance of the patient based on a comparison between the determined indication of balance and a baseline indication of balance for the patient. 
     
     
         10 . The method of  claim 1 , further comprising generating an output comprising that is sent to a display of the portable device. 
     
     
         11 . The method of  claim 10 , wherein the output comprises a visualization avatar for the patient that is animated to demonstrate movement along at least one axis based on the COM motion data. 
     
     
         12 . The method of  claim 10 , wherein the output comprises a graph that represents motion of the COM of the patient in a plane. 
     
     
         13 . A non-transitory computer-readable medium storing instructions executable by one or more processors to perform operations comprising:
 a test data interface that receives test data for a patient that represents motion of a set of sensors attached to a patient's torso to approximate the patient's center of mass during a test interval;   a test data calculator that processes the test data to provide sensor-derived data that includes acceleration data, rotational rate data and rotational position data for the test interval;   a center of mass (COM) calculator that applies a biomechanical model to the processed data to provide COM motion data representing movement of the COM in multiple dimensions for the patient during the test interval; and   a balance analyzer that determines an indication of balance for the patient based on the COM motion data.   
     
     
         14 . The non-transitory computer-readable medium of  claim 13 , wherein a portable device attached to a patient proximal the COM of the patient comprises the set of sensors. 
     
     
         15 . The non-transitory computer-readable medium of  claim 13 , wherein the set of sensors comprises an accelerometer and a gyrometer, and
 wherein the test data comprises accelerometer data and gyrometer data.   
     
     
         16 . The non-transitory computer-readable medium of  claim 13 , wherein the biomechanical model comprises at least one offset function. 
     
     
         17 . The non-transitory computer-readable medium of  claim 13 , wherein the balance analyzer computes area data in at least two orthogonal planes based on the COM motion data to determine the indication of balance,
 wherein the area data corresponds to a two-dimensional projection of the path traveled by the COM of the patient.   
     
     
         18 . The non-transitory computer-readable medium of  claim 17 , wherein the balance indicator computes volume data based on the areas computed in the at least two orthogonal planes. 
     
     
         19 . The non-transitory computer-readable medium of  claim 17 , wherein the balance analyzer analyzes the balance of the patient based on a comparison between the determined indication of balance and a baseline indication of balance for the patient. 
     
     
         20 . The non-transitory computer-readable medium of  claim 13 , further comprising an output generator that generates an output for display,
 wherein the output comprises a visualization avatar for the patient that is animated to demonstrate movement along at least one axis based on the COM motion data.