A PET FOLLOW-UP-STUDY OF RECOVERY AFTER STROKE IN ACUTE APHASICS

The neural correlates of recovery from aphasia are largely unknown. Se veral different sources of evidence, from clinical studies to neurophy siological investigations, have suggested a contribution of the contra lateral, undamaged hemisphere in recovery from aphasia. Eight patients with unilateral left hemispheric stroke were submitted to a standard language examination and to a [F-18]FDG PET study in the recent phase after stroke (within 2 weeks) and 6 months later. All patients had a s ubstantial recovery of specific aspects of language functions at the f ollow-up. Analysis of regional glucose metabolism showed hypometabolis m in structurally unaffected regions both in the left and in the night hemisphere (diaschisis), in the acute stage. Glucose metabolism incre ased significantly on both sides in all patients at the second PET stu dy. Regional analysis showed significant positive correlations between changes in metabolic values in several cortical and subcortical regio ns in the right hemisphere and changes in language performance at foll ow-up. The present findings show that an extensive, bihemispheric depr ession of metabolism is found in the acute stage after stroke in aphas ic patients. Language recovery in the first months after aphasia onset is associated with regression of functional depression (diaschisis) i n structurally unaffected regions, in particular in the right hemisphe re. (C) 1997 Academic Press, Inc.