Introduction: The vocal cord dysfunction questionnaire (VCDQ) is a validated 12 item, 5-point likert scale questionnaire used to monitor symptoms in Inducible Laryngeal Obstruction (ILO). A score higher than 12 on the VCDQ could suggest having ILO. This study aimed to investigate the internal consistency reliability of each of the 12 questions.

Method: Data was collected from 68 participants attending our one stop assessment clinic. All patients completed the VCDQ questionnaire and for those diagnosed with ILO, internal consistency of the questions was compared using Cronbach?s Alpha (?).  ILO was diagnosed using gold standard laryngoscopy.

Results:31 participants (46%) received a diagnosis of ILO. 35 (51%) a diagnosis of asthma. 14 (21%) a diagnosis of ILO and asthma. 21 (31%) had no ILO or asthma. The mean VCDQ score in ILO patients was 44. The mean VCDQ in asthma only patients was 22. The mean VCDQ score of no ILO/ asthma patients was 23. The Cronbach?s Alpha(?) of the VCDQ questionnaire completed by the participants who received a diagnosis of ILO was 0.694 rated as ?questionable? using the Cronbach Alpha descriptors. Removal of question 8 {I?m aware of other specific triggers that cause attacks} and question 9 {my symptoms are associated with an ache or itch in my throat} would result in higher Cronbach?s Alpha (?) of 0.698 and 0.731 and rated as ?acceptable? using the Cronbach Alpha descriptors. 

Conclusion:The VCDQ questionnaire is a reliable questionnaire for identifying ILO symptoms. If certain questions were removed the reliability would improve further. Further research is required to measure the reliability of the questionnaire post therapy.