Trigeminal and taste sensations of the tongue after middle ear surgery.
OBJECTIVE
To establish clinical tests for measurement of trigeminal sensitivity on the human tongue and objectively assess changes in oral trigeminal sensitivity and taste ability after chorda tympani nerve (CTN) injury.


METHODS
Prospective study.


METHODS
University hospital.


METHODS
One-hundred and twenty-six patients with unilateral middle ear diseases who underwent primary middle ear surgery.


METHODS
Trigeminal sensation was measured each operated side as well as nonoperated side both before and 14 days after surgery using 3 kinds of tests: Semmes-Weinstein sensory test (SW test), 2-point discrimination test, and the electrostimulator test. Taste function was assessed with electrogustometry (EGM) similarly.


RESULTS
The patients which the CTN was not touched (n = 6) showed no differences between preoperative and postoperative thresholds in any tests. In the patients with sectioned CTN (n=30), postoperative thresholds on the operated side were significantly higher than preoperative thresholds on the electrostimulator test, 2-point discrimination test, and EGM. In the patients with manipulated but not sectioned CTN (n = 90), postoperative thresholds were significantly higher than preoperative thresholds on the electrostimulator test and EGM. The patients with manipulated but not sectioned CTN and abnormal EGM postoperative thresholds (n = 48) showed that postoperative thresholds were significantly higher than preoperative thresholds in all tests.


CONCLUSIONS
These findings suggest that the electrostimulator test was most useful to objectively assess small changes of trigeminal sensation among the 3 tests. The finding that trigeminal sensitivity of the tongue deteriorated on the operated side after CTN injury suggests that CTN function affected both taste sensation and trigeminal sensation of the tongue.
Department of Otolaryngology, Hyogo College of Medicine, Nishinomiya City, Hyogo, Japan.
Akiko
A
Sakaguchi
Tomomi
T
Nin
Hirokazu
H
Katsura
Yasuo
Y
Mishiro
Masafumi
M
Sakagami
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002814:Chorda Tympani Nerve / Q000293:injuries* / Q000503:physiopathology / Q000601:surgery; D004192:Discrimination, Psychological / Q000502:physiology; D004432:Ear, Middle / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013649:Taste / Q000502:physiology*; D013651:Taste Disorders / Q000175:diagnosis* / Q000503:physiopathology; D013652:Taste Threshold / Q000502:physiology*; D014059:Tongue / Q000294:innervation / Q000502:physiology*