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Original Investigation
September 29, 2016

Sensory Topography of Oral Structures

Author Affiliations
  • 1Department of Otolaryngology–Head and Neck Surgery, University of California, San Francisco, San Francisco

Copyright 2017 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.

JAMA Otolaryngol Head Neck Surg. Published online September 29, 2016. doi:10.1001/jamaoto.2016.2772

Importance  Sensory function in the oral cavity and oropharynx is integral to effective deglutition and speech production. The main hurdle to evaluation of tactile consequences of upper aerodigestive tract diseases and treatments is access to a reliable clinical tool. We propose a rapid and reliable procedure to determine tactile thresholds using buckling monofilaments to advance care.

Objective  To develop novel sensory testing monofilaments and map tactile thresholds of oral cavity and oropharyngeal structures.

Design, Setting, and Participants  A prospective cross-sectional study of 37 healthy adults (12 men, 25 women), specifically without a medical history of head and neck surgery, radiation, or chemotherapy, was carried out in an academic tertiary medical center to capture normative data on tactile sensory function in oral structures.

Interventions  Cheung-Bearelly monofilaments were constructed by securing nylon monofilament sutures (2-0 through 9-0) in the lumen of 5-French ureteral catheters, exposing 20 mm for tapping action.

Main Outcomes and Measures  Buckling force consistency was evaluated for 3 lots of each suture size. Sensory thresholds of 4 oral cavity and 2 oropharyngeal subsites in healthy participants (n = 37) were determined by classical signal detection methodology (d-prime ≥1). In 21 participants, test-retest reliability of sensory thresholds was evaluated. Separately in 16 participants, sensory thresholds determined by a modified staircase method were cross-validated with those obtained by classical signal detection.

Results  Buckling forces of successive suture sizes were distinct (P < .001), consistent (Cronbach α, 0.99), and logarithmically related (r = 0.99, P < .001). Test-retest reliability of sensory threshold determination was high (Cronbach α, >0.7). The lower lip, anterior tongue, and buccal mucosa were more sensitive than the soft palate, posterior tongue, and posterior pharyngeal wall (P < .001). Threshold determination by classical signal detection and modified staircase methods were highly correlated (r = 0.93, P < .001). Growth of perceptual intensity was logarithmically proportional to stimulus strength (P < .01).

Conclusions and Relevance  Topography of normal oral cavity and oropharyngeal tactile sensation is organized in accordance to decreasing sensitivity along the anteroposterior trajectory and growth of perceptual intensity at all subsites is log-linear. Cheung-Bearelly monofilaments are accessible, disposable, and consistent esthesiometers. This novel clinical tool is deployable for quantitative sensory function assessment of oral cavity and oropharyngeal structures.