The roles of semantic networks and search efficiency in verbal fluency performance in intractable temporal lobe epilepsy

doi:10.1016/0920-1211(95)00002-R

Epilepsy Research

Volume 21, Issue 1, May 1995, Pages 19-26

https://doi.org/10.1016/0920-1211(95)00002-R Get rights and content

Abstract

Two competing hypotheses (i.e., disruption of semantic networks vs. search inefficiency) concerning the mechanisms underlying impaired semantic verbal fluency in temporal lobe epilepsy (TLE) were tested within a single paradigm. Reports that semantic verbal fluency is more impaired in left than right TLE groups were confirmed by the findings that the left TLE group produced fewer words on a supermarket fluency task than did the normal control (NC) group, and that the performance of the right TLE group was intermediate to that of the left TLE and NC groups. Because both TLE groups generated fewer words per category of supermarket items sampled, and produced a higher ratio of category labels relative to category exemplars than did the NC group, it can be surmised that TLE disrupts semantic memory networks. The findings did not support the competing hypothesis that reduced semantic verbal fluency in TLE is a manifestation of inefficient search /retrieval strategies, possibly associated with distal frontal lobe pathophysiology. Specifically, the TLE and NC groups did not differ significantly in their mean number of perseverations, intrusions, or search efficiency (operationalized as the ratio of the number of shifts between categories to the number of categories sampled).

References (38)

A.L. Benton
Differential behavioral effects in frontal lobe disease
Neuropsychologia
(1968)
C.D. Frith et al.
A PET study of word finding
Neuropsychologia
(1991)
Y. Joanette et al.
Criterion-specific reduction of verbal fluency in right-brain-damaged right-handers
Neuropsychologia
(1986)
M. Jones-Gotman et al.
Design fluency: The invention of nonsense drawings after focal cortical lesions
Neuropsychologia
(1977)
A. Martin et al.
Word production and comprehension in Alzheimer's disease: The breakdown of semantic knowledge
Brain Lang.
(1983)
R.C. Martin et al.
The effects of lateralized temporal lobe dysfunction on formal and semantic word fluency
Neuropsychologia
(1990)
E. Perret
The left frontal lobe of man and the suppression of habitual responses in verbal categorical behaviour
Neuropsychologia
(1974)
E. Rosch et al.
Basic objects in natural categories
Cognitive Psychol.
(1976)
R.M. Ruff et al.
Figural fluency: Differential impairment in patients with left versus right frontal lobe lesions
Arch. Clin. Neuropsychol.
(1994)
A.I. Tröster et al.
A comparison of the category fluency deficits associated with Alzheimer's and Huntington's disease
Brain Lang.
(1989)

A.L. Benton et al.

R.A. Bornstein et al.

Effects of temporal lobectomy for treatment of epilepsy on hemispheric functions ipsilateral to surgery: Preliminary findings

Int. J. Neurosci.

(1987)

N. Butters et al.

Episodic and semantic memory: A comparison of amnesic and demented patients

J. Clin. Exp. Neuropsychol.

(1987)

A.S. Chan et al.

An assessment of the semantic network in patients with Alzheimer's disease

J. Cognitive Neurosci.

(1993)

H.B. Coslett et al.

Frontal verbal amnesia: Phonological amnesia

Arch. Neurol.

(1991)

J. Hart et al.

Category-specific naming deficit following cerebral infarction

Nature

(1985)

R.K. Heaton

Wisconsin Card Sorting Test

(1981)

B.P. Hermann et al.

Effects of anterior temporal lobectomy on language function: A controlled study

Ann. Neural.

(1988)

B.P. Hermann et al.

Language function, temporal lobe epilepsy, and anterior temporal lobectomy

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Research reportThe roles of semantic networks and search efficiency in verbal fluency performance in intractable temporal lobe epilepsy

Abstract

Neuropsychologia

Neuropsychologia

Neuropsychologia

Neuropsychologia

Brain Lang.

Neuropsychologia

Neuropsychologia

Cognitive Psychol.

Arch. Clin. Neuropsychol.

Brain Lang.

Effects of temporal lobectomy for treatment of epilepsy on hemispheric functions ipsilateral to surgery: Preliminary findings

Int. J. Neurosci.

Episodic and semantic memory: A comparison of amnesic and demented patients

J. Clin. Exp. Neuropsychol.

An assessment of the semantic network in patients with Alzheimer's disease

J. Cognitive Neurosci.

Frontal verbal amnesia: Phonological amnesia

Arch. Neurol.

Category-specific naming deficit following cerebral infarction

Nature

Wisconsin Card Sorting Test

Effects of anterior temporal lobectomy on language function: A controlled study

Ann. Neural.

Language function, temporal lobe epilepsy, and anterior temporal lobectomy

Research report
The roles of semantic networks and search efficiency in verbal fluency performance in intractable temporal lobe epilepsy