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Steady-state evoked potentials can be recorded from the human scalp in response to auditory stimuli presented at rates between 1 and 200 Hz or by periodic modulations of the amplitude and/or frequency of a continuous tone. Responses can be objectively detected using frequency-based analyses. In waking subjects, the responses are particularly prominent at(More)
Human auditory steady-state responses (ASSRs) were recorded using stimulus rates of 78-95 Hz in normal young subjects, in elderly subjects with relatively normal hearing, and in elderly subjects with sensorineural hearing impairment. Amplitude-intensity functions calculated relative to actual sensory thresholds (sensation level or SL) showed that amplitudes(More)
OBJECTIVE To define brain activity corresponding to an auditory illusion of 3 and 6Hz binaural beats in 250Hz or 1000Hz base frequencies, and compare it to the sound onset response. METHODS Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000Hz to one ear and 3 or 6Hz higher to the other, creating an illusion of(More)
The purpose of this study was to compare cortical brain responses evoked by amplitude modulated acoustic beats of 3 and 6 Hz in tones of 250 and 1000 Hz with those evoked by their binaural beats counterparts in unmodulated tones to indicate whether the cortical processes involved differ. Event-related potentials (ERPs) were recorded to 3- and 6-Hz acoustic(More)
OBJECTIVE Independent amplitude and frequency modulation (IAFM) of a carrier tone uses two different modulating frequencies, one for amplitude modulation (AM) and one for frequency modulation (FM). This study measured the human steady-state responses to multiple IAFM tones. The first question was whether the IAFM responses could be recorded without(More)
OBJECTIVE To compare weighted averaging and artifact-rejection to normal averaging in the detection of steady-state responses. METHODS Multiple steady-state responses were evoked by auditory stimuli modulated at rates between 78 and 95 Hz. The responses were evaluated after recording periods of 3, 6 and 10 min, using 5 averaging protocols: (1) normal(More)
OBJECTIVE The number of steady-state responses evoked by the independent amplitude and frequency modulation (IAFM) of tones has been related to the ability to discriminate speech sounds as measured by word recognition scores (WRS). In the present study IAFM stimulus parameters were adjusted to resemble the acoustic properties of everyday speech to see how(More)
This article considers the efficiency of evoked potential audiometry using steady-state responses evoked by multiple simultaneous stimuli with carrier frequencies at 500, 1000, 2000, and 4000 Hz. The general principles of signal-to-noise enhancement through averaging provide a basis for determining the time required to estimate thresholds. The advantage of(More)
OBJECTIVE To define cortical brain responses to large and small frequency changes (increase and decrease) of high- and low-frequency tones. METHODS Event-Related Potentials (ERPs) were recorded in response to a 10% or a 50% frequency increase from 250 or 4000 Hz tones that were approximately 3 s in duration and presented at 500-ms intervals. Frequency(More)
OBJECTIVE To compare the magnitudes of the steady-state responses evoked by several types of stimuli, and the times required to recognize these responses as significant. DESIGN In the first two experiments, we examined auditory steady-state responses to pure tones, broadband noise and band-limited noise. The stimuli were amplitude modulated in the 75 to(More)