[Transient motor aphasia at high altitude]

Three healthy mountaineers had episodes of transient motor aphasia at 5,547, 8,000 and 7,000 metres respectively. In the three cases the comprehension was preserved. Aphasia was neither accompanied nor followed by headache, motor disturbances or any other neurologic symptoms and signs. We suspect that transient motor aphasia is more frequent at high altitude than can be concluded from its low frequency of apparition in the medical literature. Among the pathogenic hypotheses, we consider the disfunction of language-related brain areas due to vascular obstruction by microthrombi of platelets and fibrin or to selective hypocapnic-mediated vasoconstriction, but a diffuse metabolic illness cannot be ruled out.