Apparatus and method for movement coordination analysis

Abstract

Methods and devices are provided for evaluating among the limbs of a subject the distribution of impairments of the subject's ability to coordinate the muscular contractions to execute effective postural movements. The subject may be placed on two independently movable support surfaces, either of which may be fixed or sway-referenced. The subject's ability to maintain his or her equilibrium position is then monitored. In another embodiment, the subject is perturbed from a position of equilibrium. The perturbation may be caused by a displacement of the support surfaces, or by having the subject grasp a handle, which may be moved, or against which the subject may push or pull. The latency and strength of the responses of the subject's limbs are measured and compared to each other and to a normal population.

1. A device for assessing a subject's ability to utilize support surface inputs from one of the subject's first and second supporting legs, such device comprising:
 means for measuring at least one quantity related to the subject's displacement from a standing equilibrium position;  
 a fixed support surface on which the subject's first leg rests;  
 a movable support surface, on which the subject's second leg rests, the movable support surface being rotatable about a horizontal axis;  
 actuator means for rotating the movable support surface;  
 control means for receiving the quantity related to the subject's displacement from a standing equilibrium position and for controlling the actuator means so that the actuator means causes the movable support surface to rotate on a continuous basis in functional relation to the measured quantity, so that the movable support surface has a sway-reference gain greater than zero; and  
 means for measuring the subject's ability to maintain the standing equilibrium position.  
 
     
     
       2. A device for determining the extent of a subject's independent ability to maintain, by coordination of muscular responses to sensory information, a position in equilibrium, such device comprising;
 perturbing means for disturbing the subject's position in equilibrium, wherein the perturbing means include a handle for being grasped by the subject;  
 sensing means for sensing the degree of contractile activity in a plurality of muscles as the subject attempts to restore equilibrium;  
 analyzing means for determining at least one of the order or distributional relationship of such contractile activity.  
 
     
     
       3. A device for determining the extent of a subject's independent ability to maintain, by coordination of muscular responses to sensory information, a position in equilibrium, such device comprising;
 perturbing means for disturbing the subject's position in equilibrium, wherein the perturbing means include a handle for being grasped by the subject and movable along a horizontal axis;  
 sensing means for sensing the degree of contractile activity in a plurality of muscles as the subject attempts to restore equilibrium;  
 analyzing means for determining at least one of the order or distributional relationship of such contractile activity.  
 
     
     
       4. A device for determining the extent of a subject's independent ability to maintain, by coordination of muscular responses to sensory information, a position in equilibrium, such device comprising;
 perturbing means for disturbing the subject's position in equilibrium, wherein the perturbing means includes a  support means, each support means independently movable with respect to one another and linearly along a horizontal axis, for supporting a subject in equilibrium;  
 sensing means for sensing the degree of contractile activity in a plurality of muscles as the subject attempts to restore equilibrium; and 
 analyzing means for determining at least one of the order or distributional relationship of such contractile activity.  
 
     
     
       5. A device according to  claim 3 , wherein the analyzing means includes computing means for computing a quantity over time related to the levels of contractile activity in selected muscles. 
     
     
       6. A device according to  claim 4   for determining the extent of a subject's independent ability to maintain, by coordination of muscular responses to sensory information, a position in equilibrium, such device comprising:
   perturbing means for disturbing the subject's position in equilibrium, wherein the perturbing means includes a support means, independently movable linearly along a horizontal axis, for supporting a subject in equilibrium;    
   sensing means for sensing the degree of contractile activity in a plurality of muscles as the subject attempts to restore equilibrium; and    
   analyzing means for determining at least one of the order or distributional relationship of such contractile activity , wherein the analyzing means includes computing means for computing a quantity over time related to the levels of contractile activity in selected muscles.  
 
     
     
       7. A device according to  claim 2 , wherein the analyzing means includes computing means for computing a quantity over time related to the levels of contractile activity in selected muscles. 
     
     
       8. A method for assessing a subject's ability to utilize support surface inputs from one of the subject's first and second supporting legs, such method comprising:
 A. providing two support surfaces, and standing the subject on the support surface, so that each of the two support surfaces has only one leg resting thereon;  
 B. measuring at least one quantity related to the subject's displacement from the standing equilibrium position;  
 C. fixing the support surface on which the first leg rests, so that it does not move;  
 D. rotating about a horizontal axis on a continuous basis the other support surface, on which the subject's second leg rests, in functional relation to the measured quantity, so that the support surface that is moving has a sway-reference gain greater than zero; and  
 E. measuring the subject's ability to maintain the standing equilibrium position.  
 
     
     
       9. A device for assessing a subject's ability to utilize support surface inputs from one of the subject's first and second supporting legs, such method comprising:
 a fixed support surface on which the subject's first leg rests;  
 a movable support surface, on which the subject's second leg rests, the movable support surface being rotatable about a horizontal axis;  
 a compliant element for restraining the rotational motion, so that the movable support surface moves on a continuous basis in functional relation to the subject's displacement from a standing equilibrium position, so that the movable support surface has a sway-reference gain greater than zero; and  
 means for measuring the subject's ability to maintain the standing equilibrium position.  
 
     
     
       10. A method for assessing a subject's ability to utilize support surface inputs from one of the subject's first and second supporting legs, such method comprising:
   A. providing two support surfaces, and standing the subject on the support surfaces so that each of the two support surfaces has only one leg resting thereon;        B. fixing the support surface on which the first leg rests, so that it does not move;        C. permitting rotation of the subject's foot associated with the second leg as the subject sways; and        D. measuring the subject's ability to maintain an equilibrium position.