Evaluation of the High Frequency Digit Triplet test in Cystic Fibrosis
Cystic Fibrosis (CF) is an inherited condition which affects 9000 people in the UK, over half of whom are adults. Life expectancy is around 40 years but it is increasing steadily, largely due to improved treatment of chronic lung infections. However, treatment over many years with some antibiotics (“aminoglycosides”) may have toxic effects, including permanent and severe hearing loss, usually affecting both ears. Even mild hearing loss has a damaging effect on schooling and future employment prospects. The conventional hearing test - the Pure Tone Audiogram – must be performed by an audiologist using specialised equipment. It is not practical to use this test regularly in CF patients to prevent further hearing loss. We will evaluate a new hearing test - the High Frequency Digit Triplet (HFDT)
test. This test mimics how individuals hear in real life situations (such as a noisy room), requires only a computer and does not need clinically trained personnel. We will evaluate the new test in stable patients and in those about to receive intravenous antibiotics for a chest infection. We will also see if it is feasible to do the test in primary school children. If the HFDT test is accurate and practical we will apply for a new research grant which would allow us to see
if the test is accurate when performed in the home (where there may be more background noise). We could then offer this test to every CF patient in the UK over 5 years. Patients could perform this test at home and then bring the result to discuss with their doctor if antibiotic treatment is likely. We believe this test could prevent hearing loss in many people with CF and allow substantial savings both in testing and in hearing aid provision (where hearing is irreversibly damaged).