Functional imaging in the assessment of capability for recovery after stroke.

After an ischaemic lesion preserved components of a functional network are utilized for recovery from neurological defects. The hierarchy of the individual parts within the damaged network, however, determines the quality of the outcome. This could be clearly demonstrated for the complex network of language ability, for which the left temporal region plays an integrative role: only if the left temporal regions are morphologically preserved and can be reactivated in imaging studies of speech performance was the outcome of poststroke aphasia satisfying. In brain functions with a less pronounced hemispheric specialization the effect of disturbed centres in the dominant hemisphere might be less accentuated. Functional neuroimaging studies might help to estimate prognoses of functional outcome in early states after stroke and to evaluate the efficiency of strategies of rehabilitative measures and of adjuvant drug therapy.