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British Medical Bulletin 63:213-221 (2002)
© 2002 The British Council
Under-rated neuro-otological symptoms: Hoffman and Brookler 1978 revisited
Department of Neuro-otology, Division of Neuroscience and Psychological Medicine, Imperial College Faculty of Medicine, Charing Cross Hospital, London, UK
In 1978, Hoffman and Brookler published an article in The Laryngoscope to challenge prevailing views on the lack of diagnostic power of certain symptoms often reported by patients to neuro-otologists. Some of these ‘under-rated neuro-otological symptoms’ include complaints of non-rotational dizziness, blurred and double vision, and the development of visual motion hypersensitivity in patients with balance disorders. In this review, I revisit these visual symptoms in the light of new findings from our laboratory. Double vision due to skew eye deviation can indeed occur in peripheral vestibular disease when there is a large, acute peripheral imbalance of vestibular function. It is more frequent and severe in brain stem disease. In both cases, it is explained by disruption of the torsional vestibular ocular reflex. It is usually assumed that damage to the otolith underlies the emergence of skew diplopia, but recent evidence shows that the vertical canal system is likely to be partly responsible as well. The other ‘under-rated symptom’ revisited here is what patients describe as dizziness when watching moving objects or whilst walking in visually busy surroundings such as supermarkets. Recent work has shown that this ‘visual vertigo’ emerges in patients who, in addition to suffering from a vestibular disorder, have increased visual dependence. Visual dependence denotes subjects who preferentially use vision, as opposed to vestibular or proprioceptive input, for spatial orientation and postural control. We do not know as yet what makes some vestibular patients become extremely visually dependent. However, we have provided evidence for Hoffman and Brookler's impression that visually triggered complaints should not be summarily dismissed, as they often point to an underlying vestibular disorder.