Neuromechanics of movement in lower limb amputees

PhD ceremony: Ms. C. Curtze, 16.15 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Neuromechanics of movement in lower limb amputees

Promotor(s): prof. K. Postema, prof. E. Otten

Faculty: Medical Sciences

The design of prosthetic devices and rehabilitation programs can be improved. This is Carolin Curtze’s conclusion on the basis of her dissertation project. Curtze studied the complex interaction between brain, body, prosthesis and environment.

By means of a self developed measurement device, Curtze investigated the roll-over properties of prostheses and found that these were crucial for standing stability. Furthermore, shoes appeared to have an impact on this property. Although the roll-over shapes found in prosthetic feet approximated the roll-over shapes of able-bodied people, amputees do not walk symmetric due to limitations of the prosthesis. Adjustment strategies of amputees during walking can only be made by the sound limb, for which the patient’s balance control is crucial. Curtze developed a number of tests to determine the balance control. Amputees appeared to use efficient strategies to compensate for the shortcomings of the prosthesis. Moreover, the passive properties of the prosthesis contributed to balance control.

Curtze studied environmental influences by challenging the participants through an evoked forward fall and walking over an irregular surface. Amputees were equally efficient in recovering from an impending fall as able-bodied people, irrespective of whether they led with their prosthetic or sound limb. When walking on irregular surface, amputees increased the amount of lateral arm swing to increase stability. No adjustments in the stepping behavior were found.

In general, walking is a highly automated process. The research showed that amputees need to adjust their movement to the limitations of current prosthetics. For future developments, the technical properties of prostheses should be adapted to the motor abilities of the amputee, instead of the other way around; innovations need to be patient driven instead of technology driven. The research results furthermore advocate training programs to be maximally challenging, thereby improving self-confidence.