Post operative supplementary motor area syndrome: clinical features and outcome

The syndrome of the supplementary motor area (SIMA) is not well recognized and its features can easily be confused with pyramidal weakness. The author s describe the SMA syndrome in six patients who underwent surgery for tumou rs located in the SMA, three in the dominant and three in the non-dominant hemispheres. All of them underwent complete resection of the anatomically d escribed SMA, with partial (n=4) or total resection (n=2) of the tumour. In the postoperative period, all these patients exhibited reduction of sponta neous movements and difficulty in performing voluntary motor acts to comman d in the contralateral limbs, although the tone in the limbs was maintained or increased. The function of these limbs in serial automatic motor activi ties (for example, dressing and walking) was, however, relatively unaffecte d. Speech deficits were seen in only one of three patients with the dominan t SMA syndrome. Besides a severe impairment of volitional movements, the sa lient features of the deficits in this syndrome are hemineglect and dysprax ia or apraxia involving the contralateral limbs. All patients recovered the ir motor functions over varying periods of time ranging from one to a few w eeks. Long-term follow-up (median 24 months) in five patients revealed comp lete return of function in the affected limbs. It is important to recognize the entity of the SMA syndrome and differentiate it from the deficits that result from operative damage to the motor cortex as the deficits associate d with the former are likely to recover almost completely over a short peri od of time.