Recovery of gait after stroke

Abstract

Revised edition of the digital PhD thesis, 14-03-2006 In the Netherlands annually about 30,000 people suffer a stroke for the first time. One third of these stroke patients die within the first year, while 41% experience long term disabilities. This makes stroke a major disease in medical and in socio-economic terms. Not just on society but also, and far most, on the afflicted individual and his or her environment the impact is felt of a sustained stroke. Following a stroke a person's independence in moving about may be significantly compromised. The expected level of walking to a great extent determines the expected level of activities of daily living and possible discharge to home.

This thesis describes the long term recovery of hemiplegic gait in severely affected stroke patients. Based on the application of a repeated measurement research design, data were obtained within the first post-stroke year period. This information subsequently enabled the identification of time-related changes and was used to address the following main questions:

Are intensive stroke rehabilitation programmes, implemented within the early and subacute post-stroke phases, worthwhile in terms of long term functional gains and can this long term recovery be estimated early after stroke onset for better individualized reliable therapeutic goal setting and discharge planning?

For this purpose, early and late recovery patterns were studied as functional recovery after stroke tends to be non-linear and time-dependent. Subsequently, this information was used in the interpretation of some of the mechanisms involved in the long term recovery of hemiplegic gait and the impact of intensity of therapeutic interventions on this recovery.

The main findings of the studies presented in the first part of this thesis indicate predictive relationships between early determinants and late outcome and the relevance of measuring frequently and longitudinally in order to take into consideration the non-linear time-dependent relationship of covariates with recovery of gait after stroke. In the second part it is demonstrated that the long term effects of intensity of stroke rehabilitation, implemented during the initial 20 post-stroke weeks, are maintained for up to one year. However, a significant number of patients with incomplete recovery showed improvements or deterioration of walking ability and ADL beyond the error threshold between 6 and 12 months post-stroke.

Several mechanisms involved in stroke recovery are discussed, such as recovery of penumbral tissues, neural plasticity, resolution of diaschisis and behavioural compensation strategies. Rehabilitation is believed to modulate this logistic pattern of recovery, most likely by interacting with these underlying processes. Our prediction models suggest that outcome is largely defined within the first weeks post-stroke.