An acoustic stimulus is presented to the external auditory canal; energy is transferred from the ear canal through the middle ear, some of which is reflected and some absorbed by the tympanic membrane and external ear structures. The premise behind the immittance instrumentation used to measure the acoustic reflex is the ability to accurately measure changes in reflected energy occurring from s...

The present study is concerned with conditioned reflex changes in background and evoked activity of the neuronal population of the auditory cortex (AI) in three waking cats. For the elaboration of a conditioned blink reflex, a series of eight clicks was used as the signal. The unconditional stimulus was rhythmic blowing of air at the eye. During the elaboration of a positive conditioned reflex ...

Measurements of middle ear (ME) acoustic power flow and related measures (e.g., reflectance, absorbance, impedance, resistance, and reactance) have several important advantages over other measures of acoustic impedance, such as the clinical “gold standard” measure, tympanometry. In addition to its wide bandwidth and ease of use, the absorbance curve, on a dB scale, has a shape that is similar t...

The acoustic startle (ASR) is a transient motor response to an unexpected, intensive stimulus. The response is determined by stimulus parameters such as its intensity, rise time and duration. The dependence of the ASR on the stimulus duration is more complex than could be assumed from physical properties of acoustic pulse. This effect attracted the attention of few researchers. Some authors rep...

Postural and eye-blink reactions to acoustic startle probes were examined in 24 volunteers, who completed two blocked conditions (baseline, startle). A postural reaction during the startle condition demonstrated a reflexive movement in the anterior-posterior direction, which was not observed during the baseline condition. This reflexive response was positively associated with the eye-blink refl...

Propylene glycol (PG) is commonly used as a solvent for odorous chemicals employed in studies of the olfactory system because PG has been considered to be odorless for humans and other animals. However, if laboratory rats can detect the vapor of PG and if exposure to this influences behaviors, such effects might confound data obtained from experiments exposing conscious rats to odorants dissolv...

Prepulse inhibition (PPI) of the acoustic startle reflex has been proposed as a neurophysiological measure of sensorimotor gating. There is high test-retest reliability of both startle magnitude and PPI in non-psychiatric subjects. The present study examined the stability of the acoustic startle reflex and its modulation in patients with schizophrenia. Startle measurements were performed in 19 ...

Tympanometric peak pressure, peak compensated static acoustic admittance (peak Ytm) and acoustic stapedius reflex (ASR) thresholds were obtained for a representative sample of 1565 older Australians who were participants in the Blue Mountains Hearing Study (BMHS). No significant age or gender effects were found for tympanometric peak pressure. Peak Ytm measures, however, decreased with age in t...

BACKGROUND Previous research has noted an age effect on the temporal integration of the acoustic reflex for a noise activator. PURPOSE To determine whether the age effect earlier noted for a noise activator will be noted for a tonal activator. RESEARCH DESIGN Comparison of ARTs of younger and older groups at activating stimulus durations of 12, 25, 50, 100, 200, 300, 500, and 1000 msec. S...

A 17-item questionnaire probing professional preparation and current practices in central auditory assessment was mailed to 500 audiologists selected randomly from the membership directory of the American Academy of Audiology. Data from 183 respondents, representing a 37 percent response rate, were analyzed. The majority of respondents reported minimal academic and clinical preparation in asses...