Article

In contrast to lesions of the visual and somatosensory cortex, lesions of the
auditory cortex are not associated with self-evident contralesional deficits.
Only when two or more stimuli are presented simultaneously to the left and right,
contralesional extinction has been observed after unilateral lesions of the
auditory cortex. Because auditory extinction is also considered a sign of
neglect, clinical separation of auditory neglect from deficits caused by lesions
of the auditory cortex is challenging. Here, we directly compared a number of
tests previously used for either auditory-cortex lesions or neglect in 29
controls and 27 patients suffering from unilateral auditory-cortex lesions,
neglect, or both. The results showed that a dichotic-speech test revealed similar
amounts of extinction for both auditory cortex lesions and neglect. Similar
results were obtained for words lateralized by inter-aural time differences.
Consistent extinction after auditory cortex lesions was also observed in a
dichotic detection task. Neglect patients showed more general problems with
target detection but no consistent extinction in the dichotic detection task. In
contrast, auditory lateralization perception was biased toward the right in
neglect but showed considerably less disruption by auditory cortex lesions.
Lateralization of auditory-evoked magnetic fields in auditory cortex was highly
correlated with extinction in the dichotic target-detection task. Moreover,
activity in the right primary auditory cortex was somewhat reduced in neglect
patients. The results confirm that auditory extinction is observed with lesions
of the auditory cortex and auditory neglect. A distinction can nevertheless be
made with dichotic target-detection tasks, auditory-lateralization perception,
and magnetoencephalography.
CI - Copyright A(c) 2012 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS