NOTES ON THE CLINICAL FEATURES AND PATHOLOGY OF POST-CONCUSSIONAL VERTIGO, WITH ESPECIAL REFERENCE TO POSITIONAL NYSTAGMUS BY

THE most prominent features of the post-concussional syndrome are headache, emotional lability, difficulty in concentration and giddiness. Of these, giddiness in one form or another is a particularly persistent and common feature. Thus, Friedman and his collaborators (1945) describe its occurrence in 50 per cent; Glaser (1937) in 60 per cent; and Linthicum and Rand (1931) in 90 per cent of cases. In some instances, true rotational vertigo occurs of a type suggestive of a labyrinthine lesion. This, however, is far from common and Linthicum and Rand describe it in only 4 of 36 cases. In the majority, the character of the giddiness is ill-defined and is generally described in such terms as un-steadiness, a tendency to fall, wavering of objects, a dazed feeling, or confusion in crowds or traffic. Its pathology is easy to understand in the minority of subjects in whom there is gross evidence of a labyrinthine injury, often with radiological evidence of a labyrinthine fracture accompanied by severe deafness with loss of the caloric responses. In the majority of cases, however, its pathological mechanism remains obscure. Deafness is usually absent, as emphasized by Mygind (1918), Barr6 and Greiner (1932) and Bremer (1932). Furthermore, little assistance appears to have been derived from the results of formal tests of vestibular function. Thus, Bremer attributed the vertigo to a vestibular hypo-excitability. On the other hand Barr6 and Greiner (1932) and Portmann and Despons (1937) found hyper-excitability. The clinical importance of post-concussional giddiness is derived from its disabling character and the frequency of its occurrence. There is, therefore, an urgent need for some further enquiry into its pathological basis, and this we have been encouraged to undertake by certain recent developments, both in the technique of the tests of vestibular function and in our knowledge of the symptomatology and pathology of organic disorders of the vestibular system. These will be discussed in some detail. by guest on