Constraints on predicting functional recovery after stroke: Application of clinical, laboratory, neurophysiologic, and neuroimaging parameters.

Methodologic issues in statistical prediction of functional outcome from stroke are considered, and a model that defines various sources of constraint on the processes involved in recovery is elaborated. Prediction is relatively easy for the upper and lower bands of stroke survivors but becomes significantly more complex forthe middle band of patients, for whom inpatient rehabilitation services may be considered potentiallycost effective. Sources of constraint on functional outcome include biological factors related to the stroke and to comorbid medical conditions, cognitive factors related to higher cortical functions impaired by the stroke, premorbid personality and emotional response factors, and socioeconomic factors such as the availability of a social support system. In examining recovery of function at the impairment level, issues related to how various functions in the brain are reorganized after injury become important. New information about the capacity of functional brain subsystems to reorganize after focal damage due to stroke may help improve the ability to generate prognoses and may also guide the development and application of rehabilitation strategies.