Novel Adaptation of a Validated Tactile Aesthesiometer to Evaluate Laryngopharyngeal Sensation

Abstract

Objectives: To evaluate laryngopharyngeal sensation at specific subsites using a novel adaptation of a buckling force aesthesiometer for delivery of calibrated tactile stimuli.Study Design: Cross-sectional. Methods: Twenty-two healthy adults (12 men, 10 women) were tested for responses to tactile forces, using 30-mm 6-0, 5-0, and 4-0 nylon monofilaments to map sensation of the aryepiglottic (AE) fold, lateral pyriform sinus (PS), and medial PS bilaterally. The outcome measures were the laryngeal adductor reflex (LAR) and patient reported rating of perceptual strength.Results: Rates of triggered LAR response grew monotonically with increasing tactile force at a mean (SD) stimulus duration of 663 ( 164) msec across all three subsites. The AE fold and medial PS had similar profiles and were the most responsive, while the lateral PS was the least responsive. Low force (6-0) response rate was ≤14% for all subsites. High force (4-0) response rate was 91% for AE fold and medial PS, and 23% for lateral PS. The perceptual strength gradient was in the lateral to medial trajectory. Conclusion:Normative data for LAR response rates to low, medium, and high stimulation forces will be useful to assess sensory dysfunction in a variety of laryngopharyngeal disorders, including aspiration, dysphagia, chronic cough, and spasmodic dysphonia. In turn, that information will guide the creation of innovative treatments. LAR response profiles to low and high force stimuli will inform the development of screening tools to diagnose laryngopharyngeal hypersensitivity and hyposensitivity conditions.

Laryngeal Adductor Reflex Movement Latency Following Tactile Stimulation

“…The rate of triggered LAR response increases monotonically with greater tactile stimulus force delivery to the aryepiglottic fold, medial pyriform sinus, and lateral pyriform sinus subsites of the laryngopharynx in healthy, asymptomatic adults. 24…”

Aesthesiometer‐Based Testing for Laryngopharyngeal Hyposensitivity

“…When this procedural inefficiency occurs, the aesthesiometer assembly is retracted and redeployed. Continuation with 6–0 monofilament use would be expected to increase test procedure time and refine the LAR threshold estimate for <14% of positive responses 11 . Accepting this maximum error rate for overestimation of the LAR response threshold appears to be an acceptable tradeoff in the development of a patient‐friendly and time‐efficient sensory test protocol to screen for laryngopharyngeal hyposensitivity.…”

“…This procedure was repeated 20 times for each suture size and across three different lots. Buckling force of the 5–0 monofilament was 0.11 gram and 4–0 monofilament was 0.30 g 11 …”

“…The main study objective was to formulate an aesthesiometer‐based testing protocol that would incorporate findings from the following key considerations: 1) monotonic dependence of positive LAR response on stimulation force, 11 2) 5–0 monofilament and 4–0 monofilament dichotomous LAR response outcome classifier features and performance, 3) LAR response outcome agreement and disagreement matrix to the stimulation forces of 5–0 and 4–0 monofilaments, and 4) LAR response outcome test–retest reliability. Beyond threshold estimation of the triggered positive LAR response, an implementable decision tree protocol could identify patients at risk for laryngopharyngeal hyposensitivity and its clinical sequelae.…”

Stereo Laryngoscopic Impact Site Prediction for Droplet-Based Stimulation of the Laryngeal Adductor Reflex

“…Manual, tactile stimulation of the laryngeal mucosa has also been reported to show a poor reproducibility [20]. Very recently, efforts have been made in an interesting study by Strohl et al to deliver calibrated tactile stimuli with a buckling monofilament [21]. However, the precise LAR stimulation time, required for highly accurate reflex latency quantification, remains difficult to identify with such a manual approach, especially at low videolaryngoscopy frame rates [22].…”