Studies on asterognosis and amyotrophy of the hand in brainstem syndromes. Relation to the symptomatology of tumours at the spinocranial junction.

Fifteen patients with symptoms of an ischaemic lesion in the vertebrobasilar territory were investigated with respect to the presence of asterognosis and amyotrophy of the hand muscles. Stereognostic disturbances were noted in 4 patients with a medullary lesion and in two patients with brainstem syndromes of less defined level. The findings in these cases suggested a lesion of the medial lemniscus. Amyotrophy of the hand muscles was not seen in these patients. The absence of association of astereognosis and amyotrophy of the hand muscles in syndromes due to lower brainstem lesions supports the view that these symptoms, when occurring conjointly in foramen magnum tumours, originate from two different lesions and are caused by different mechanisms.