Demographical and clinical characteristics
The mean age of the 57 patients was 67 ± 8 years for men (n = 41) and 71 ± 10 years for women (n = 16), with a mean age at onset of muscle weakness at 57 ± 9 years for men and 59 ± 10 years for women. Most patients (n = 39, 68%) presented with weakness of the quadriceps muscles. Dysphagia was the presenting symptom in four patients (7%), at a mean age of 64 years. Mean duration of symptoms of muscle weakness was 10 ± 7 years for men and 12 ± 5 years for women. The investigated group did not differ significantly from the original population group of 86 patients with regard to age (at onset) and disease duration. The male sex however, was slightly over-represented in the investigated group compared with the group of 86 patients (male to female ratio: 2:1).
Questionnaire (n = 57)
Thirty-seven patients (65%) had symptoms of dysphagia. Women reported dysphagia more often compared to men (88 vs. 56%). Of these patients, 26 reported both IP and AR symptoms (46%), seven reported symptoms of IP only (12%) and four had exclusively AR symptoms (7%). The vast majority of these patients had symptoms on a daily basis. Solid food was the most likely to get stuck in the throat (n = 22, 71%), yet only one patient (2%) used ground food (Table 1).
Twenty patients who acknowledged dysphagia on the questionnaire (54%) had not spontaneously disclosed swallowing complaints to a physician before.
Videofluoroscopy (n = 43)
In 34 patients (79%) VFS was abnormal. Abnormal findings were equally frequent in men and women.
Thirty-three patients (77%) had signs of IP repetitive swallowing (n = 24, 56%), residues in the piriform sinus (n = 19, 44%) and valleculae (n = 16, 37%), or cricopharyngeal sphincter dysfunction (n = 16, 37%, Fig. 1).
Only one patient showed aspiration during VFS; this patient also had repetitive swallowing, vallecular and piriform sinus residues and IEDT. Twenty-three (53%) other patients had aspiration-related signs of whom 18 (43%) had IEDT. Normal swallowing function was observed in nine patients.
A Zenker’s diverticulum was found in eight patients (19%). The ostium of the diverticulum was invariably located just above the upper oesophageal sphincter.
Comparison between questionnaire and videofluoroscopy
In 25 patients who reported symptoms of IP, a VFS was performed. Of these, 23 had corresponding IP signs on VFS (positive predictive value: 0.92). The highest positive predictive values were calculated for the questions regarding food getting stuck in the throat (91%) and whether or not repeated swallows (92%) were needed. Nineteen patients (83%) showed repetitive swallowing, 15 (65%) had a piriform sinus residue, 13 (57%) had a vallecular residue and 10 (44%) demonstrated sphincter dysfunction. Remarkably, two (8%) patients had symptoms of IP, but a normal VFS. Ten out of 33 patients with IP signs on VFS had no symptoms of IP on questionnaire. The sensitivity of the questionnaire concerning IP was 0.70, the specificity 0.80 and the negative predictive value 0.44.
Twenty-three patients who underwent VFS reported AR symptoms on the questionnaire. Confirmation of aspiration on VFS was obtained in only one patient. Fourteen (65%) other patients showed one or more different AR signs on VFS (positive predictive value: 0.65). Nine out of 24 patients with AR signs on VFS had no symptoms of aspiration on the questionnaire. The sensitivity concerning AR signs was 0.63, the specificity 0.58 and the negative predictive value 0.55.
Abnormalities were more frequently detected by VFS than based on the questionnaire scores, 79 versus 65%.