Dichotic listening with forced attention in patients with temporal lobe epilepsy: Significance of left hemisphere cognitive dysfunction

Gramstad, Arne; Engelsen, Bernt A.; Hugdahl, Kenneth

doi:10.1111/j.1467-9450.2006.00503.x

Cited by 7 publications

(3 citation statements)

References 41 publications

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“…There are, however, no reasons to believe that the results were due to epilepsy rather than the hallucinations. Gramstad et al. (2006) found that patients with left temporal lobe epileptic focus did not show reduced performance on the same dichotic listening task as the one used in the present study.…”

Section: Discussionsupporting

confidence: 47%

An fMRI study of auditory hallucinations in patients with epilepsy

Korsnes¹,

Hugdahl²,

Nygård³

et al. 2010

Epilepsia

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SUMMARYPurpose: The aim of the study was to investigate behavioral and brain activation in nonpsychotic hallucinating individuals. Auditory hallucinations are reported by patients with epilepsy, although less frequent than visual hallucinations are. If behavioral and neuronal activation patterns in hallucinating patients with epilepsy are found to be similar to what has been found in hallucinating patients with schizophrenia, this would support a unique neuronal representation for auditory hallucinations cutting across diagnostic groups. Methods: We report behavioral and functional magnetic resonance imaging (fMRI) data from six epilepsy patients experiencing auditory hallucinations compared with six healthy control subjects. The participants had to report which of two simultaneously presented simple speech sounds they perceived on each trial, using a dichotic stimulus presentation mode. Results: The results showed that the patients failed to show an expected right ear advantage on the task, and they also showed significantly reduced activation in temporal, frontal, and cingulate cortex areas. Discussion: The results are discussed in relation to a view that neuropsychological and functional neuroimaging indices of auditory hallucinations may be orthogonal to diagnostic category and not unique to patients with schizophrenia.

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Section: Discussionsupporting

confidence: 47%

An fMRI study of auditory hallucinations in patients with epilepsy

Korsnes¹,

Hugdahl²,

Nygård³

et al. 2010

Epilepsia

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“…As evidence for this inhibitory callosal role of attention, callosal-lesioned or resected patients show elevated traditional ear advantages for speech, and no effects from attention directed to either ear in modulating this asymmetry (Pollmann et al, 2002; Westerhausen and Hugdahl, 2008). Epilepsy patients may also experience changes in auditory cortex curtailing normal, inhibitory processes used in suppressing irrelevant stimuli (Gramstad et al, 2006). In particular, Bougeard and Fischer (2002) reported increased ipsilateral N1s in epileptics after temporal lobectomy, suggesting a potentially inhibitory function of contralateral hemisphere on ipsilateral inputs.…”

Section: Discussionmentioning

confidence: 99%

Elastic attention: enhanced, then sharpened response to auditory input as attentional load increases

Neelon

Williams

Garell

2011

Front. Hum. Neurosci.

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A long debate in selective attention research is whether attention enhances sensory response or sharpens neural tuning by suppressing response to non-target input. In fact, both processes may occur as a function of load: an uncertain listener might use a broad attentional filter to enhance responses to all inputs (i.e., vigilance), yet employ sharpened tuning to focus on hard to discriminate targets. The present work used the greater signal gain, anatomical precision, and laterality separation of intracranial electrophysiological recordings (electrocorticograms) to investigate these competing effects. Data were recorded from acoustically-responsive cortex in the perisylvian region of a single hemisphere in five neurosurgery patients. Patients performed a dichotic listening task in which they alternately attended toward, away from, or completely ignored (silent reading) tones presented to designated ears at varying presentation rates. Comparisons between the grand-averaged event-related potential (ERP) waveforms show a striking change in the effect of selective auditory attention with attentional load. At slower presentation rates (low-load), ERPs were overall enhanced in response to both input channels and regardless of attended ear, including a significant enhancement of ipsilateral input. This result supports a broadly enhancing model of attention under low perceptual load conditions. At the fastest rate, however, only responses to attended inputs contralateral to grid location remained enhanced. This result supports an increasing suppression, or “sharpening,” of neural responses to non-targets with increasing attentional load. These data provide support for an elastic model of attention in which attentional scope narrows with increasing load.

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“…2 In particular, the side of TLE has differential impact on the neuropsychological impairment with dysfunction of the dominant temporal lobe affecting verbal and non-dominant temporal lobe affecting primarily visuo-spatial cognitive function. [3][4][5][6] How TLE affects higher and more specialized cognitive functions remains unknown.…”

Section: Introductionmentioning

confidence: 99%