Semantic Network Organization in Temporal Lobe Epilepsy Patients.
Abstract number :
3.077
Submission category :
Year :
2001
Submission ID :
629
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
B. Bell, PhD, Neurology, University of Wisconsin, Madison, WI; R. Sanner, U of Wisconsin, Madison, WI; M. Seidenberg, PhD, Psychology, Finch UHS/Chicago Medical School, North Chicago, IL; B. Hermann, PhD, Neurology, U of Wisconsin, Madison, WI; R. Sheth,
RATIONALE: Recent evidence suggests semantic memory might be impaired at the group level in temporal lobe epilepsy (TLE) patients. In previous studies of schizophrenia and Alzheimer[ssquote]s disease, two statistical techniques, multidimensional scaling (MDS) and cluster analysis (CA), were applied to data from a category fluency test to assess organization of the semantic system. The results were consistent with semantic network impairment in these patient groups versus controls (Aloia et al., 1996; Chan et al., 1993). We applied MDS and CA to category fluency test data in order to study semantic organization in TLE.
METHODS: For the category fluency test, participants (TLE n = 78, Control n = 70) were instructed to generate as many animal names as possible within 60 seconds. Eight of the most commonly generated animal names were analyzed. Based on the order in which these names were produced, the distance between each of the possible pairs of animals was calculated. For each group, MDS and CA produced a cognitive map and identified clusters of animals which indicated the proximities and associations among the animals.
RESULTS: The geography of the semantic maps and the subordinant clusters produced by MDS and CA were quite similar for the TLE and control groups. When the TLE patients with an early onset of recurrent seizures (n = 39) were compared to a randomly selected subset of the controls (n = 35), semantic organization again appeared similar for the two groups. Animals were separated primarily on a wild versus domesticated dimension, with two logical subgroups evident within both the wild and tame divisions.
CONCLUSIONS: TLE patients and controls showed similar semantic organization for selected exemplars from the animal category. Thus, a specific aspect of the semantic network appeared intact in TLE patients. We studied the associations among only a small sample of exemplars from the animal category, because other animal names were produced too infrequently. The eight animals examined are all prototypical category exemplars, with names that are acquired very early in childhood (Battig & Montague, 1969; Morrison et al., 1997). In the future, we plan to assess the semantic network for less prototypical animals in TLE patients and controls using a different semantic task.
Support: NIH NS37738 and an Epilepsy Foundation Young Investigator Award.