Characteristics of olfactory dysfunction in patients with temporal lobe epilepsy

Ayako Motoki; Naoki Akamatsu; Tomoyuki Fumuro; Ayako Miyoshi; Hideaki Tanaka; Koichi Hagiwara; Shinji Ohara; Takashi Kamada; Hiroshi Shigeto; Hiroyuki Murai

doi:10.1016/j.yebeh.2021.108402

Characteristics of olfactory dysfunction in patients with temporal lobe epilepsy

Epilepsy Behav. 2021 Dec:125:108402. doi: 10.1016/j.yebeh.2021.108402. Epub 2021 Nov 12.

Authors

Affiliations

¹ International University of Health and Welfare Graduate School of Medicine, Tokyo, Japan.
² International University of Health and Welfare Graduate School of Medicine, Tokyo, Japan; Epilepsy Center, Fukuoka Sanno Hospital, Fukuoka, Japan; International University of Health and Welfare School of Medicine, Department of Neurology, Narita, Japan. Electronic address: akamatsu@iuhw.ac.jp.
³ International University of Health and Welfare School of Medicine, Department of Neurology, Narita, Japan.
⁴ Epilepsy Center, Fukuoka Sanno Hospital, Fukuoka, Japan.
⁵ Epilepsy Center, Fukuoka Sanno Hospital, Fukuoka, Japan; Kyushu University Division of Medical Technology, Fukuoka, Japan.
⁶ International University of Health and Welfare Graduate School of Medicine, Tokyo, Japan; International University of Health and Welfare School of Medicine, Department of Neurology, Narita, Japan; International University of Health and Welfare School of Medical Sciences at Okawa, Department of Laboratory Medicine, Okawa, Japan.

PMID: 34775249
DOI: 10.1016/j.yebeh.2021.108402

Abstract

Objective: To determine the characteristics of olfactory dysfunction in patients with temporal lobe epilepsy (TLE).

Methods: Odor identification was assessed using the odor stick identification test for Japanese (OSIT-J, full score 12 points) in 65 patients with TLE and in 74 controls.

Results: The mean OSIT-J score was significantly lower in patients with TLE (mean ± SD = 8.1 ± 2.8; median = 9) than in the control subjects (mean ± SD = 10.6 ± 1.1; median = 11) (P < 0.005). Olfactory dysfunction (hyposmia/anosmia) was associated with bilateral seizure foci and older age of onset in TLE. Patients who underwent temporal lobectomy for hippocampal sclerosis did not show significant decline after long-term recovery. The Indian ink part of OSIT-J was useful for the detection of olfactory deficits in patients with TLE (sensitivity = 47%, specificity = 93%). Patients with TLE tended to have preserved olfactory ability for stimulating odors and for familiar odors of daily life.

Significance: We observed characteristic odor identification deficits for individual odors used in OSIT-J. Our study findings provide deeper insight into the underlying mechanism of olfactory function in patients with TLE and may be beneficial in the clinical management of these patients.

Keywords: Anosmia; Epilepsy; Olfaction; Smell; Temporal lobe.

MeSH terms

Aged
Epilepsy, Temporal Lobe* / complications
Humans
Odorants
Olfaction Disorders* / etiology
Seizures
Smell