LIST and LINT: Sentences and numbers for quantifying speech understanding in severely impaired listeners for Flanders and the Netherlands

A Dutch sentence test (LIST) and a Dutch number test (LINT) have been developed and validated for the accurate measurement of speech reception thresholds (SRT) in quiet and in noise with severely hearing-impaired individuals and cochlear implant recipients in Flanders and the Netherlands. The LIST consists of 35 lists of 10 sentences of equal known difficulty uttered by a female speaker; while the LINT consists of 400 numbers (1-100) by two male and two female speakers. Normative values were determined at fixed S/N ratios and using the adaptive method (Plomp Mimpen, 1979), yielding identical results for SRT and slope. For the LIST, average fitted SRTs were 27.1 (0.9) dB SPL in quiet and -7.8 dB (0.2) SNR in noise. In addition, the LIST in noise displayed a steep discrimination function (17%/dB) and good reliability (within-subject standard deviation=1.2 dB). For the LINT average fitted SRTs in quiet were 20.7 (0.9) dB SPL and about -9.0 dB SNR in noise. Again, the slopes of the performance intensity functions were relatively steep, i.e. 8.5%/dB in quiet and 15.2%/dB in noise, suggesting that the LINT is accurate and efficient and thus capable of reflecting subtle changes in performance. First data with cochlear implanted subjects show that both LIST and LINT are feasible and are capable of mapping a large range of hearing disabilities.