Studies of UCC/RCC with abnormalities of cough hypersensitivity and laryngeal findings
| First author [ref.] | Subjects evaluated and number studied | Abnormal cough triggers In RCC/UCC | Laryngeal paresthesia | Throat clearing in UCC/RCC | Voice abnormalities and upper airway dyspnoea in UCC/RCC | Laryngeal abnormalities on endoscopy | Other findings |
| Vertigan [6] | 111 chronic cough patients (55 out of 111 with PVFM also) | Average of 8 triggers noted for each participant | 41% reported warning sensations with most identifying throat as the site of trigger | Noted but percentage of patients with this symptom not specified | Abnormal voice and dyspnoea scores in chronic cough and cough plus PVFM patients | 55 chronic cough with PVFM included in analysis | Talking, cigarette smoke, cold air and irritability in throat identified as most frequent triggers. |
| Ryan [21] | 24 subjects with chronic persistent cough | Not reported | Not reported | Not reported | Not reported | 14/24 noted with PVFM | Abnormal extrathoracic airway hyper-reponsiveness using hypertonic saline in cough+PVFM group |
| Vertigan [22] | 53 RCC patients | 100% with one or more cough triggers | Seen in 94% | Not reported | Not reported | Shortness of breath reported as a cough trigger | Categorised tussive and non-tussive triggers to capture hypertussia and allotussia |
| Bucca [23] | 61 UCC | Not reported | Not reported | Not reported | Not reported | 66% of UCC patients had abnormal LHR | LHR seen not only in UCC but also in GORD (62) asthma (41), rhinosinusitis (208) |
| Ryan [24] | 62 patients | 50% with laryngeal hypersensitivity | 63% with central reflex sensitisation | Not reported | 76% with voice changes | Not reported | This was a placebo-controlled study of gabapentin in chronic cough that showed higher cough improvement in those with central sensitisation. |
| Vertigan [25] | 33 RCC | Not reported | RCC patients had worse laryngeal paresthesia scores compared to controls | Not reported | Worse VHI scores and DSI as compared to controls | Not reported | 57% of RCC had abnormal fall in forced inspiratory flow (FIF50)following hypertonic saline and worse compared to control groups |
| Hilton [26] | 100 consecutive chronic cough patients | 79% with hypertussia 72% with allotussia | 75% with neck sensations | ∼50% with throat clearing | Not reported | Not reported | Correlation between urge-to-cough sensation intensity and total LCQ score. |
| Vertigan [27] | 20 patients with RCC | Not reported | Abnormal LHQ with correlation with cough frequency | Not reported | Abnormal mean VHI values in RCC group compared to controls | Laryngeal motor dysfunction with breathing in 47% RCC (67% with odour challenge). Mediolateral constriction of false vocal cords in 45% with incomplete or abnormal vocal cord closure in 75% of RCC group. | Specialised voice testing and timed swallow test different in RCC group as compared with controls. 69% with of 27 out of 69 patients that had abnormal cough had PVFM |
| Won [28] | 62 patients with RCC | 100% of patients with two or more cough triggers | 100% of patients with at least one abnormal sensation | Not reported | Not reported | Not assessed | Correlations between LCQ and number of laryngeal sensations, number of cough triggers, CHQ score |
| Current study | 60 patients RCC/UCC | 100% with one or more cough triggers | Seen in 97% | Seen in 45% of patients | VHI abnormal in 43% and DI in 75% of patients | Functional laryngeal abnormalities in 88% patients | Correlations between LCQ and VHI and DI noted |
RCC: chronic refractory cough; UCC: unexplained chronic cough; PVFM: paradoxical vocal fold motion; LHR: laryngeal hyper-responsiveness; LHQ: laryngeal hypersensitivity questionnaire; LCQ: Leicester Cough Questionnaire; CHQ: Cough Hypersensitivity Questionnaire; DSI: Dyspnea Symptom Index; VHI: Voice Handicap Index; DI: dyspnoea index.