Analysis of ceiling effects occurring with speech recognition tests in adult cochlear-implanted patients

This article presents a simple method of analysing speech test
scores which are biased through ceiling effects. Eighty
postlingually deafened adults implanted with a MED-EL COMBI 40/40+
cochlear implant (CI) were administered a numbers test and a
sentence test at initial device activation and at 1, 3, 6, 12 and
24 months thereafter. As a measure for speech recognition
performance, the number of patients who scored at the `ceiling
level' (i.e. at least 95% correct answers) was counted at each test
interval. Results showed a quick increase in this number soon after
device activation as well as a continuous improvement over time (
numbers test: 1 month: 51%; 6 months: 73%; 24 months: 88%; sentence
test: 1 month: 33%; 6 months: 49%; 24 months: 64%). The new method
allows for the detection of speech recognition progress in CI
patient samples even at late test intervals, where improvement
curves based on averaged scores are usually assuming a flat shape.
Copyright (C) 2004 S. Karger AG, Basel.