The effect of visual cues on scoring of clinical word-recognition tests

Diagnostic Precision of Open-Set Versus Closed-Set Word Recognition Testing

Purpose The aim of the study was to examine the precision of forced-choice (closed-set) and open-ended (open-set) word recognition (WR) tasks for identifying a change in hearing. Method WR performance for closed-set (4 and 6 choices) and open-set tasks was obtained from 70 listeners with normal hearing. Speech recognition was degraded by presenting monosyllabic words in noise (-8, -4, 0, and 4 signal-to-noise ratios) or processed by a sine wave vocoder (2, 4, 6, and 8 channels). Results The 2 degraded speech understanding conditions yielded similarly shaped, monotonically increasing psychometric functions with the closed-set tasks having shallower slopes and higher scores than the open-set task for the same listening condition. Fitted psychometric functions to the average data were the input to a computer simulation conducted to assess the ability of each task to identify a change in hearing. Individual data were also analyzed using 95% confidence intervals for significant changes in scores for words and phonemes. These analyses found the following for the most to least efficient condition: open-set (phoneme), open-set (word), closed-set (6 choices), and closed-set (4 choices). Conclusions Closed-set WR testing has distinct advantages for implementation, but its poorer precision for identifying a change than open-set WR testing must be considered.

Backward masking of tones and speech in people who do and do not stutter

PURPOSE

There is evidence of an auditory-perceptual component of stuttering, and backward masking (BM) is a task to explore that role. Prior research reported poorer thresholds for BM tones in a group of children who persisted in stuttering compared to those for a group that did not persist. This study examined BM for adults who stutter for tones and for speech, which tests a phonetic aspect of hearing.

METHOD

Eight persons who stutter (PWS) were closely matched with eight controls (PNS) in terms of phonological abilities, verbal span tasks, age, sex and non-verbal intelligence. These participants were examined for their ability to recognize vowel-consonant (VC) speech syllables and tones in BM paradigm with 0 ms and 300 ms masker to signal onset conditions.

RESULTS

PWS showed significantly poorer performance for speech syllable recognition in quiet and in conditions with masking noise. The pattern of speech errors was similar in both groups, but the PWS produced more errors. A significant condition by group interaction in backward masking for tones was attributed to higher masked thresholds in PWS than in PNS in the 0 ms delay condition for BM for tones.

CONCLUSION

This was the first study to examine BM for speech in PWS. Results provide support for a small auditory-perceptual deficit for speech understanding in adults who stutter that was revealed in the absence of a lexical context. The speech results are explained in terms of possible indistinct phoneme boundaries in PWS and the effects of vowel context in speech recognition.