Influence of temporal lobe epilepsy and temporal lobe resection on olfaction

Doty, Richard L. and Tourbier, Isabelle and Neff, Jessica K. and Silas, Jonathan and Turetsky, Bruce and Moberg, Paul and Taehoon, Kim and Pluta, John and French, Jacqueline and Sharan, Ashwini D. and Sperling, Michael J. and Mirza, Natasha and Risser, Anthony and Baltuch, Gordon and Detre, John A. (2018) Influence of temporal lobe epilepsy and temporal lobe resection on olfaction. Journal of Neurology . ISSN 1432-1459 (Published online first)

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Abstract

Although temporal lobe epilepsy (TLE) and resection (TLR) impact olfactory eloquent brain structures, their influences on olfaction remain enigmatic. We sought to more definitively assess the influences of TLE and TLR using three well-validated olfactory tests and the tests’ associations with the volume of numerous temporal lobe brain structures. The University of Pennsylvania Smell Identification Test and an odor detection threshold test were administered to 71 TLE patients and 71 age- and sex-matched controls; 69 TLE patients and controls received an odor discrimination/ memory test. Fifty-seven patients and 57 controls were tested on odor identification and threshold before and after TLR; 27 patients and 27 controls were similarly tested for odor detection/discrimination. Scores were compared using analysis of variance and correlated with pre- and post-operative volumes of the target brain structures. TLE was associated with bilateral deficits in all test measures. TLR further decreased function on the side ipsilateral to resection. The hippocampus and other structures were smaller on the focus side of the TLE subjects. Although post-operative volumetric decreases were evident in most measured brain structures, modest contralateral volumetric increases were observed in some cases. No meaningful correlations were evident pre- or post-operatively between the olfactory test scores and the structural volumes. In conclusion, we demonstrate that smell dysfunction is clearly a key element of both TLE and TLR, impacting odor identification, detection, and discrimination/memory. Whether our novel finding of significant post-operative increases in the volume of brain structures contralateral to the resection side reflects plasticity and compensatory processes requires further study.

Item Type: Article
Research Areas: A. > School of Science and Technology > Psychology
Item ID: 24285
Notes on copyright: This is a post-peer-review, pre-copyedit version of an article published in Journal of Neurology. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00415-018-8891-y
Useful Links:
Depositing User: Jon Silas
Date Deposited: 23 May 2018 10:04
Last Modified: 19 Nov 2018 15:28
URI: http://eprints.mdx.ac.uk/id/eprint/24285

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