Abstract:
A multiple sleep latency test (MSLT) was carried out to determine the
impact on sleep onset latency (SOL) of disturbing speech sound and speech
that was masked with rain, SOL was measured using polysomnography
(PSG) and electroencephalography (EEG) responses were time-locked to
designated parts of the disturbing speech. For all sound conditions subjectively perceived disturbance and speech intelligibility were measured.
The analysis showed that sound condition did not have a significant effect on the SOL, but a trend was found that speech increased the SOL,
and masking speech reduced the SOL, soft rain appeared to mask more
effectively than loud rain. Sound condition did have significant effect on
disturbance: Speech was rated as more disturbing than No Sound, Soft
mask was equally disturbing as Speech, and only the Loud mask reduced
the disturbance. The same effect was found for subjective intelligibility.
Global prototype EEG responses showed event-related potential (ERP)
components N100, N200, and P300 in the Speech and Soft mask condition, but not in the Loud mask condition. This pattern corresponded the
most with subjective intelligibility, which was related to subjective disturbance, and therefore the found EEG response strengths can be a predictor
for disturbance.
Keywords: Noise masking, subjective disturbance, speech intelligibility, sleep onset latency, MSLT, prototype EEG response, event-related
potential, auditory evoked potential.
