Taste deficits after middle ear surgery for otosclerosis: taste somatosensory interactions

Abstract

The aim of this study was to evaluate the postoperative consequences of chorda tympani reclining during middle ear surgery for otosclerosis. Electrogustometric taste thresholds were measured at 11 loci on the tongue and the soft palate in 14 patients before surgery, and 8 d, 1 month and (in some cases) 6 months after surgery. A significant increase in thresholds was observed on the ipsilateral side of the tongue after surgery. The extent of the deficit and the recovery time course depended on tongue locus. The tip of the tongue displayed a limited deficit, suggesting bilateral chorda tympani innervation. The edge of the tongue was less impaired than the dorsal or the lateral tip loci; it may be dually innervated by both chorda tympani and glossopharyngeal nerves in humans, as already shown in rats. Likewise for the fungiform papillae located just anterior to the circumvallate papillae. Somatosensory early complaints suggest a derepression of chorda tympani on lingual nerve signals. In a second stage, relief of complaints before electrogustometric threshold recovery suggested trigeminal compensation of the chorda tympani deficit. Relief of complaints seems to involve central integrative processes, whereas the evolution of electrogustometric threshold represents the actual recovery time course of chorda tympani peripheral sensitivity.

Nonsynonymous single nucleotide polymorphisms in human tas1r1, tas1r3, and mGluR1 and individual taste sensitivity to glutamate

“…Electrogustometric threshold 790S was measured at 9 loci in 51 subjects; medication, smoker status, and the number of dental deafferentations were noted (43)(44)(45). Electrogustometric threshold 790S was measured at 9 loci in 51 subjects; medication, smoker status, and the number of dental deafferentations were noted (43)(44)(45).…”

Feasibility of preservation of chorda tympani nerve during noninflammatory ear surgery: A systematic review

“…Electrogustometry testing and interpretation are described differently in these studies. Table gives an overview of reported results . In addition to the EGM results, Mahendran et al reported a weak correlation between the degree of experienced symptoms and EGM results ( r = 0.2291; r 2 = 0.05250) …”

“…Sone et al report a pooled mean score of preoperative EGM thresholds for patient with a preserved and sacrificed CTN . Berteretche et al reported a significant increase of EGM detection thresholds in all loci ( P < 0.05) except for the palatal locus . By comparing EGM results to the contralateral not operated side, no significant change in the EGM thresholds was obtained .…”

“…Of the included studies, four report postoperative EGM results . Mahendran et al and Sone et al compared patients with a preserved CTN to patients with a sacrificed CTN, whereas Berteretche et al and Sakagami et al only reported outcomes from patients with sacrificed CTNs . Sone et al report a pooled mean score of preoperative EGM thresholds for patient with a preserved and sacrificed CTN .…”

Cutting the chorda tympani: not just a matter of taste

“…5,6 There are many reports suggesting that section of the chorda tympani leads to more severe and persistent taste symptoms. 1,3,5,6,20,21 The dilemma for otological surgeons is not whether to cut or preserve the chorda tympani but, rather, whether to cut or retain severely traumatised chorda tympani nerves. Based on the reported three cases, it is impossible to answer this question.…”