Time perception

Time perception

Time perception
Time perception

Time perception

A number of studies have shown that adults who stutter are likely to perform more poorly than adults who do not stutter when they are required to dis-criminate between small time differences in auditory signals (Hall & Jerger, 1978; Kramer, Green, & Guitar, 1987). More recently, these findings have been corroborated by Barasch, Guitar, McCauley, and Absher (2000), who found that their group of 20 adults who stuttered were less able to accurately judge the lengths of silent intervals and tones than their nonstuttering peers. Add-itionally, a negative correlation was found between severity of stuttering and the ability to correctly estimate the length of short tones. Salmelin et al. (1998) compared the neuromagnetic responses of a group of nine people who stut-tered to a similar sized control group during mime reading and choral reading
They found that functional organization of the auditory cortices was different amongst the group who stuttered, namely that there were changes in the left auditory cortical representation, which was more strongly noted in the mimed speech than the choral speech. Finally, Molt’s (2003) auditory event-related potentials (ERP) analysis found that in addition to ear preference differences a group of 16 adults who stuttered showed greater variability in their ERP responses and waveform shapes, and increased latency of component P300 when subjected to a series of competing auditory stimuli at different intensity levels. (The P300 waveform component reflects cortical recognition on behalf of the speaker that the significant auditory stimulus has taken place. This is opposed to N110 or P200 peaks which are thought to be obligatory products of production.) Consistent with earlier findings, latency of response for the adults who stuttered were longer for competing linguistic stimuli than non-linguistic stimuli, although these differences were not statistically significant
Molt concedes that there are a number of potential explanations for these findings, but offers reduced language processing ability as one likely factor

 

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