Avian agnosia: A window into auditory semantics.

The functional and neural organisation of auditory knowledge is relatively poorly understood. The breakdown of conceptual knowledge in semantic dementia has revealed that pre-morbid expertise influences the extent to which knowledge is differentiated. Whether this principle applies to a similar extent in the auditory domain is not yet known. Previous reports of patients with impaired auditory vs. intact visual expert knowledge suggest that expertise may have differential effects upon the organisation of auditory and visual knowledge. An equally plausible alternative, however, is that auditory knowledge is simply more vulnerable to deterioration. Thus, expertise effects in the auditory domain may not yet have been observed because knowledge of auditory expert vs. non-expert knowledge has yet to be compared. We had the opportunity to address this issue by studying SA, a patient with semantic dementia and extensive pre-morbid knowledge of birds. We undertook a systematic investigation of SA's auditory vs. visual knowledge from matched expert vs. non-expert categories. Relative to a group of 10 age, education and IQ matched bird experts, SA showed impaired auditory vs. intact visual avian knowledge, despite intact basic auditory perceptual abilities. This was explained by independent effects of modality and expertise. Thus, he was also disproportionately impaired for auditory vs. visual knowledge of items from non-expert categories. In both auditory and visual modalities, his performance was relatively more impaired on tests of non-expert vs. expert knowledge. These findings suggest that, while auditory knowledge may be more vulnerable to deterioration, expertise modulates visual and auditory knowledge to a similar extent.

Flunarizine, the vestibular system and migraine.

The vestibular function was extensively investigated in 75 patients suffering from migraine. Pathological findings were present in 62 patients (82.6%). With the exception of position nystagmus, vestibular abnormalities were not related to migraine characteristics. Fifty-six patients were treated with flunarizine 10 mg daily for three months. A favourable effect on headache was obtained in 44 patients (78.5%). Flunarizine therapy influenced significantly gaze nystagmus and position nystagmus. The latter tended to be related to anti-migraine efficacy. Other electronystagmographic parameters were not substantially influenced. The authors assume that the vestibular abnormalities in migraine are side phenomena, the clinical relevance of which, at least during the headache-free phase, is not yet well understood.