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E Gottesman

Publications and source records attributed to E Gottesman.

3 recordsLinked to original sources
PubMed2001

Temporal non-linearities of the cochlear amplifier revealed by maximum length sequence stimulation.

OBJECTIVES: The objective of this study was to examine whether temporal non-linearities of the cochlear amplifier, as reflected by otoacoustic emissions (OAEs), exist and are distinct from any recording system non-linearities. METHODS: Maximum length sequence stimulation, at various stimulus rates, was used to evoke OAEs from normally hearing subjects. Recordings from a 2cc cavity were also made. The data were analyzed to obtain the linear response and estimates of the slices of the 2nd and 3rd order Volterra kernels. This provided a measure of two and 3 click non-linear temporal interactions, respectively. RESULTS: The results showed that temporal non-linearities of OAEs do exist, are stable and repeatable within individuals and have properties that differ from those shown by the conventional linear response. Whilst some of the non-linear response properties conformed to the expected pattern, of increasing amplitude with increase in stimulus rate, there are some areas in which they show an unpredicted complexity. CONCLUSIONS: Whilst system non-linearities could be found, there was no difficulty in distinguishing between the physiological and system non-linear components. New areas of research and application may result from the use of these new OAE responses.

Acoustic Stimulation↗
PubMed1997

Ultrasound evaluation of the paralyzed diaphragm.

Ultrasound has been used to evaluate diaphragm thickness in the zone of apposition of the diaphragm to the rib cage. The purpose of this study was to determine if ultrasonography could distinguish between a paralyzed and normally functioning diaphragm. We predicted that a paralyzed diaphragm would be atrophic and not shorten, therefore it would be thin and not thicken during inspiration. Thirty subjects (five with bilateral diaphragm paralysis, seven with unilateral diaphragm paralysis, three with inspiratory weakness but normally functioning diaphragms, and 15 healthy control subjects) had diaphragm ultrasound performed with a 7.5 to 10.0 MHz transducer placed over the lower rib cage in the mid-axillary line. The thickness of the diaphragm (tdi) was measured to the nearest 0.1 mm at FRC (t(di)FRC) and TLC (t(di)TLC). Diaphragm thickening during inspiration (delta t(di)) was calculated as (t(di)TLC - t(di)FRC)/t(di)FRC. In patients with unilateral paralysis, t(di) and delta t(di) for the paralyzed hemidiaphragm were significantly less than those values for the normally functioning hemidiaphragm (1.7 +/- 0.2 mm versus 2.7 +/- 0.5 mm [mean + SD] p < 0.01 for t(di), and -8.5 +/- 13% versus 65 +/- 26% [p < 0.001] for delta t(di)). The t(di) and delta t(di) for patients with bilateral diaphragm paralysis were significantly less than those values for the healthy volunteers (1.8 +/- 0.2 versus 2.8 +/- 0.4 and -1 +/- 15% versus 37 +/- 9% for t(di) and delta t(di), respectively) (p < 0.001). We conclude that ultrasound measurements of t(di) and delta t(di) can be used to determine if a diaphragm is paralyzed and confirm our predictions that a chronically paralyzed diaphragm is atrophic and does not thicken during inspiration.

Adult↗