Identification of Spinal Reflexes

Identification of Spinal Reflexes

De Vlugt, E.

Van der Helm, F.C.T. (promotor)

Design, Engineering and Production

2004-05-25

Visco-elasticity of joints is important for the maintenance of the human body posture and can in two manners be regulated. By means of cocontraction of antagonistic muscle groups and by neural reflexive feedback of muscle length and muscle strength, measured both by means of sensors in the muscles. The impact of the reflexive regulation is considerable and infestation of this system can give serious motor deviations, like at the Parkinson's Disease. Except anatomical knowledge is there still little clear concerning of the functionality of reflexes. This comes because there is no adequate measurement technique during natural movements to quantify the neuromuscular system. During my promotion research I have developed and applied experimental techniques with which the gain of several neural feedback pathways can be measured. Techniques have been developed for posture tasks and have been applied on the human arm. The results indicate that the reflexive system is highly adaptable and under certain circumstances works as an optimum controller. There seems to be a trade-off between two contrary properties: the magnitude of the visco-elasticity and the dynamic stability of the joint. Or, high reflexive feedback gains are desirable but are possible that mechanical oscillation occurs due to the neural time delay of the reflexive system. Such a dynamic analyses are new and make it possible to study the role of reflexes during natural movement. Benefits of this study ranges from new fundamental issues to clinical diagnostic tools.

reflexive control
human arm
posture maintenance
system identification
stability

http://resolver.tudelft.nl/uuid:6a4cd23e-b791-4bc4-acc6-a7011cdb85bd

9077595422

Institutional Repository

doctoral thesis

(c) 2004 E. de Vlugt