Both subjective and objective evidence of laryngeal dysfunction may be common in individuals with chronic cough and cough hypersensitivity syndrome (CHS), according to a study published in the Journal of Allergy and Clinical Immunology: In Practice.
Laryngeal dysfunction may also contribute to CHS mechanisms, and could potentially benefit from interventions such as speech pathology.
Researchers recruited 69 individuals with chronic cough, vocal cord dysfunction (VCD), and muscle tension dysphonia (MTD), as well as healthy controls. The purpose of the study was to determine the presence and severity of laryngeal dysfunction in individuals with chronic cough and compare these findings with known VCD and MTD. Researchers hypothesized that laryngeal dysfunction would be present in individuals with chronic refractory cough and that it would be similar in individuals with VCD and MTD.
The number of coughs per hour was significantly greater in the clinical groups compared with coughs in the healthy control group (P <.001); however, there was no significant difference identified between the clinical groups (Bonferroni corrected P >.00167). The mean voice handicap scores (VHI) in the clinical groups combined were worse (P <.001) and outside the normal range compared with controls. However, no difference between VCD and either cough or MTD was identified (P =.868 and P =.046, respectively). Mean Laryngeal Hypersensitivity Questionnaire scores were higher and outside the normal range in the clinical groups compared with controls (P <.001).
Values for auditory perceptual voice analysis and electroglottography (EGG) were significantly worse in clinical groups compared with healthy controls. However, there was no difference between clinical groups in EGG, while there was a difference in the auditory perceptual voice analysis (P =.005). There were no differences in clinical groups or between clinical and control groups in phonation frequency range values (P =.976 and P >.05, respectively).
All participants with VCD and 45% of participants with MDT had a triggered laryngeal motor dysfunction affecting respiration in response to the odor challenge (P <.011), while 45%, 93%, and 64% of CRC, VCD, and MTD participants, respectively, experienced moderate to severe mediolateral constriction of the false vocal cords during phonation. Worse timed swallow test results were found in the clinical groups compared with controls, but no differences were identified between clinical groups. Finally, researchers were unable to find a correlation between the presence of a cough and laryngeal motor dysfunction affecting respiration or between the presence of a cough and laryngeal motor dysfunction affecting phonation (rs = –0.234; P =.062 and rs = –.018; P =.454, respectively).
Researchers concluded that the pattern of laryngeal motor dysfunction and the prevalence and severity of laryngeal hypersensitivity in individuals with chronic cough were similar to those observed in individuals with VCD and MTD. Therefore, laryngeal dysfunction could possibly be a feature in CHS. Based on these findings, clinicians are encouraged to assess the need for treatments in addition to traditional cough management strategies in individuals with CRC, such as speech therapy to treat abnormal voice function, impaired voice quality of life, and laryngeal motor dysfunction that affects the individual’s respiration or phonation.
Vertigan AE, Kapela SM, Kearney EK, Gibson PG. Laryngeal dysfunction in cough hypersensitivity syndrome: a cross-sectional observational study [published online May 2, 2018]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2018.04.015