Die Ableitung olfaktorisch evozierter Potenziale in Patienten mit limbischer Enzephalitis

Zusammenfassung

Ziel der Studie In dieser Studie wurde erstmals das Riechvermögen bei Patienten mit limbischer Enzephalitis (LE) mittels olfaktorisch evozierter Potenziale (OERP) untersucht.

Methodik Bei 19 LE Patienten (9 weibliche, 10 männliche Patienten, mittleres Alter 47 Jahre) und 19 gesunden Kotrollprobanden (GK) wurde das Riechvermögen mittels psychophysischer Schwellen-Diskrimination-Identifikations-Testung (SDI) und mittels OERPs bestimmt.

Ergebnisse 10 LE Pat. (53%) hatten eine Hyposmie, 2 Pat. (11%) eine funktionelle Anosmie und 7 Pat. (36%) waren normosmisch. Der SDI-Mittelwert±Standardabweichung betrug bei den LE-Patienten 27,3±6,7; bei den GK 34,7±2,2. Der SDI-Wert der LE Patienten war im Vergleich zu den GK signifikant vermindert (p<0,0001). Alle untersuchten Patienten mit eingeschränktem Riechvermögen zeigten pathologische OERPs.

Schlussfolgerung Riechstörungen konnten gehäuft bei LE Patienten nachgewiesen werden. Möglicherweise sind hierfür strukturelle Schädigungen des limbischen Systems, das an der Weiterverarbeitung von olfaktorischen Informationen beteiligt ist, ursächlich. Die Ableitung von OERPs erwies sich als geeignetes objektives Untersuchungsverfahren zur Detektion von Riechstörungen bei LE Patienten.

Abstract

Objective Limbic encephalitis (LE) refers to an inflammatory process localized to structures of the limbic system that causes different neurologic and psychiatric disorders. To our knowledge, this is the first study investigating the olfactory function with olfactory evoked potentials (OEP) of patients with paraneoplastic or autoimmune encephalitis.

Methods 19 LE patients (9 female, 10 male, mean age 47 years) and 19 age- and sex-matched healthy controls (HC) were tested. The Threshold Discrimination Identification test (TDI) was used to test orthonasal olfactory function. OEPs were recorded for objective olfactometry.

Results 10 LE patients (53%) were hyposmic, 2 patients anosmic (11%) and 7 patients normosmic (36%). Their mean TDI value±standard deviation was 27.3±6.7. All LE patients with olfactory dysfunction also showed pathological OEPs. All 19 HCs were normosmic with a mean TDI value of 34.7±2.2. There was a significant reduction of the LE patients’ TDI score compared to the HC (p<0.0001).

Conclusions Olfactory dysfunction seems to be a frequent symptom in LE patients. This might be due to structural changes of the limbic system. OEPs were a suitable method to detect olfactory dysfunction in these patients.

Schlüsselwörter

limbische Enzephalitis - Olfaktorisch Evozierte Potenziale - Riechtestung - Riechstörung

Key words

limbic encephalitis - olfactory evoked potentials - olfactory testing - olfactory dysfunction

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