Letters to the Editor Cochlear sound-movement and musical misperception

Griffiths et al. (1997b) reported a 75-year-old man with a right hemisphere infarction which was supposedly causing misperception of sound-source movement and amusia. This contravenes Morgan’s Canon, that no behaviour should be explained in terms of higher psychological processes until simpler physiological or sensory mechanisms have been excluded. Griffiths et al. (1997a) described another patient with sound movement detection deficit and a trapezoid body lesion, and wondered if other patients with lesions in the auditory pathways would show similar deficits. In fact, Sir Alexander Ogston in his Cavendish Lecture of 1890 has already done so, showing conclusively that an inflammatory hydrops (his words) of the labyrinth due to pressure changes could produce this and other subtle auditory defects. Ogston’s main point (Ogston, 1890), as true now as it was then, was that subclinical Menière’s disease was very common but often missed by doctors. Thus, the patient of Griffith et al. (1997a) had problems hearing speech in noise, rotatory vertigo, and dextral headaches with tinnitus, yet there was no mention of any cochlear lesion. Also, from my experience, her pure tone audiogram appeared virtually diagnostic of bilateral hydrops. Despite bemoaning the absence of accurate audiometry, Ogston nevertheless came up with the identical characteristic pattern of low-tone and high-tone loss with intact mid-tones. He also stressed that hydrops symptoms could vary from hour to hour, so a single audiogram is worse than useless. Both ears often fluctuate independently, so that the worst ear can differ. The first case of Griffiths et al. (1997b) also had a mild hearing loss similar to hydrops since it extended to the lowest frequencies. This must be a more plausible cause of his unexpected sound-movement defect than any brain lesion. Did their patient have any of the hydrops symptoms listed by Ogston? Ogston measured the external horizontal and vertical fields of hearing carefully, showing that in hydrops the points of most acute hearing shifted to different parts of the auditory field, giving rise to predictable distortions of sound localization, even in unilateral cases. In one of his patients ‘this difficulty was so decided that when crossing the street, if a carriage chanced to be approaching, he became confused, not knowing from what direction the noise of the wheels was advancing, or whether one or more vehicles were