Results
We recruited 85 participants (15 children and 70 adults), giving a total
of 170 ears. One case was lost-to-follow up.
Completion of the questionnaire took an average of 6 minutes (range 1-14
minutes). In 23 ears wax precluded a diagnosis, and in a further 9,
technical faults interrupted data capture. Therefore, we analysed
questionnaire data for 138 ears.
For otoscopy, we obtained video data for 138 ears. However, experts
considered three videos inadequate for tele-diagnosis (poor view of ear
canal and/or tympanic membrane), leaving 135 cases for this method.
Gold standard diagnosis was achieved in all remaining cases, with 56
classified as normal external and middle ear, 22 CSOM, 21 otitis
externa, 9 inactive tympanic membrane perforation, and 4 AOM.
Performance of each diagnostic method compared to the gold standard is
summarised in Table 1.
For prediction model diagnosis using the questionnaire, no particular
symptom or combination of symptoms reliably differentiated diagnostic
categories. For a symptom in isolation, sensitivity for a named
diagnosis varied from 33-76%, except for presence of otorrhoea, which
had 95% sensitivity for CSOM. Specificity varied between 67-80%.
Non-expert (nurse) diagnosis performed well for specificity (90-99% for
all diagnoses) but poorly for sensitivity (<43% for all
diagnoses).
Remote expert diagnosis also performed well for specificity (86-99%),
but again less well for sensitivity (32-100%).