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Dive into the research topics where Edward G. Pasanen is active.

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Featured researches published by Edward G. Pasanen.


Journal of the Acoustical Society of America | 1976

Lateralization at high frequencies based on interaural time differences

Dennis McFadden; Edward G. Pasanen

Sensitivity to interaural time differences at high frequencies is demonstrated in a number of experiments. Two types of waveforms are used—bands of noise and two‐tone complexes. Variables studied are rate and depth of fluctuation of the envelope, overall intensity, and additivity of interaural time information across frequency regions. In many conditions of listening, sensitivity to interaural time differences at high frequencies compares favorably with sensitivity at low frequencies—good performace requires only tens of microseconds of interaural time delay.Subject Classification: [43]65.62, [43]65.68.


Journal of the Acoustical Society of America | 1988

Partial dissociation of spontaneous otoacoustic emissions and distortion products during aspirin use in humans

Craig C. Wier; Edward G. Pasanen; Dennis McFadden

Otoacoustic emissions (OAEs) of two types--spontaneous and evoked distortion products--were studied before, during, and following a period of aspirin use. As previously reported, aspirin consumption uniformly reduced the spontaneous OAEs (SOAEs) to unmeasurable or extremely low levels. Aspirin consumption also reduced the amplitude of the evoked distortion products (EDPs) but did not eliminate them entirely. The amplitude of the EDP and its change with aspirin consumption were related to both the proximity of the EDP to the frequency of the SOAE and to the level of the primaries producing the EDP. At low primary levels, even with the SOAE absent (due to aspirin consumption, or suppression), EDPs near the SOAE frequency were 10-20 dB higher than when they were 100 Hz away from the SOAE frequency.


Hearing Research | 1984

Aspirin-induced hearing loss as a model of sensorineural hearing loss

Dennis McFadden; H. S. Plattsmier; Edward G. Pasanen

Performance in forward-masking, temporal-integration, and gap-detection tasks was measured in five normal-hearing subjects before and during a five-day period of aspirin use. The drug regimen was 3.9 g per day, taken in four equal doses at 6-h intervals. In the subjects showing substantial temporary hearing loss induced by the aspirin, (1) forward masking declined at about a normal rate as the masker-to-signal interval was increased, (2) the temporal-integration functions were flatter than normal, and (3) detection of a temporal gap was worse than normal at low sound-pressure levels (SPLs) but was essentially normal at levels above about 60 dB SPL. These aspirin-induced changes in performance are similar to the differences observed between normal listeners and listeners with mild sensorineural hearing loss. Thus, temporary, aspirin-induced hearing loss offers promise as a model condition for sensorineural hearing loss. The advantages offered by this model include all those typically attributed to within-subjects experimental designs, as well as the ability to manipulate the amount of hearing loss. Its primary disadvantages are that the hearing loss is not asymmetrically distributed toward the high-frequency region, as it typically is with sensorineural deafness, and there are large individual differences in the amount of temporary hearing loss induced by fixed doses of aspirin.


Journal of the Acoustical Society of America | 1999

SPONTANEOUS OTOACOUSTIC EMISSIONS IN HETEROSEXUALS, HOMOSEXUALS, AND BISEXUALS

Dennis McFadden; Edward G. Pasanen

Click-evoked otoacoustic emissions (CEOAEs) were previously shown to be significantly less strong in homosexual and bisexual females than in heterosexual females. Here it is reported that the spontaneous otoacoustic emissions (SOAEs) of those same 60 homosexual and bisexual females were less numerous and weaker than those in 57 heterosexual females. That is, the SOAEs of the homosexual and bisexual females were intermediate to those of heterosexual females and heterosexual males. The SOAE and CEOAE data both suggest that the cochleas of homosexual and bisexual females have been partially masculinized, possibly as part of some prenatal processes that also masculinized whatever brain structures are responsible for sexual orientation. For males of all sexual orientation, the SOAEs were less numerous and weaker than for the females, and there were no significant differences among the 56 heterosexual, 51 homosexual, and 11 bisexual males. All subjects passed a hearing screening test. When all SOAEs above 3000 Hz were excluded (as a control against incipient, undetected hearing loss) the same results were obtained as with the full range of data (550-9000 Hz). The differential use of oral contraceptives by the heterosexual and nonheterosexual females also could not explain the differences in their OAEs.


Hearing Research | 1996

Additional findings on heritability and prenatal masculinization of cochlear mechanisms: Click-evoked otoacoustic emissions

Dennis McFadden; John C. Loehlin; Edward G. Pasanen

A previous demonstration of a substantial genetic contribution to the expression of spontaneous otoacoustic emissions (SOAEs) is here extended to an aspect of click-evoked otoacoustic emissions (CEOAEs). CEOAEs were measured in the same twins and non-twins used for the SOAE heritability study. The stimuli were 100-microsecond clicks presented a nominal rate of 2/s; the emitted waveforms from 50 clicks were summed, and a 20-ms sample of that averaged waveform (beginning 6 ms after click presentation) was subjected to spectral analysis. The total power in the spectrum from 1 to 5 kHz in this temporal segment of the CEOAE waveform was used as the primary dependent variable. This overall power was significantly greater in female and right ears than in male and left ears, but the difference between dark- and light-eyed subjects was not significant. The overall power in the two left, and two right, ears of monozygotic co-twins was more highly correlated than in dizygotic co-twins, and structural modeling indicated that about 65-85% of the individual variation in the expression of CEOAE power could be attributed to genes-essentially the same heritability estimate as obtained previously from the SOAE data. Within-subject correlations between CEOAE power and number of SOAEs ranged from about 0.3 to 0.7, suggesting that these two forms of otoacoustic emission may depend upon somewhat different aspects of the same underlying mechanism and, thus, that heritability estimates based on one measure are not completely redundant to those from the other. While the average spectral power of the CEOAEs in opposite-sex dizygotic (OSDZ) females was smaller than that in same-sex dizygotic (SSDZ) females- and thus approached the value for males-the difference did not achieve statistical significance. Thus, the evidence for a prenatal masculinizing effect was less definitive in these CEOAE data than in the SOAE data obtained from the same subjects. An interpretation that accounts for both the CEOAE and SOAE results is that the strength of the so-called cochlear amplifiers is under genetic control that is to some extent mediated and/or modified through prenatal exposure to androgens. The indicated direction of effect is that weak cochlear amplifiers result when prenatal androgen levels are high. Under this view, then, androgen level contribute both to the sex differences observed in otoacoustic emissions and the prenatal masculinizing effects observed in opposite-sex twins, and they may be a factor in individual differences in OAE expression as well. Additionally it is shown that, although the powers of the CEOAE waveforms were reasonably highly correlated for the two ears of subjects in all groups, and across MZ co-twins, cross-correlations on the fine structures of those same pairs of CEOAE waveforms were essentially zero-presumably owing largely to the synchronizing of (different) SOAE frequencies in the ears being compared.


Clinical Neuroscience Research | 2005

Physiological evidence of hypermasculinization in boys with the inattentive type of attention-deficit/hyperactivity disorder (ADHD)

Dennis McFadden; J. Gregory Westhafer; Edward G. Pasanen; Caryn L. Carlson; David M. Tucker

Abstract Attention-deficit/hyperactivity disorder (ADHD) is more common in boys than in girls, suggesting that prenatal androgen exposure may play a role in etiology. Click-evoked otoacoustic emissions (CEOAEs) and relative finger length are measures known to exhibit sex differences early in life, also suggesting that prenatal androgen exposure plays a contributing role. CEOAEs and the lengths of the fingers were measured in boys and girls aged 7–15 who were diagnosed as having different types of ADHD. All six possible pairwise length ratios were calculated for the four fingers of each hand. The CEOAEs measured in boys diagnosed as ADHD/Inattentive were substantially smaller than those of either the boys diagnosed as ADHD/Combined or the Control boys, whose mean CEOAEs were alike. Similarly, most of the finger-length ratios (FLRs) were smaller for boys diagnosed as ADHD/Inattentive than for either ADHD/Combined or Control boys. Both of these outcomes represent a hypermasculinization of the boys diagnosed as ADHD/Inattentive. Thus, two quite different physiological measures suggest that these boys diagnosed as ADHD/Inattentive may have been exposed to higher-than-normal levels of androgens at some stage early in development. In accord with both Cantwells proposal for validating psychiatric disorders and previous suggestions in the literature, these findings support the hypothesis that the Combined and Inattentive groups represent different disorders, not versions of a single disorder.


Hormones and Behavior | 2006

Sex differences in otoacoustic emissions measured in rhesus monkeys (Macaca mulatta)

Dennis McFadden; Edward G. Pasanen; Jessica Raper; Henry S. Lange; Kim Wallen

Click-evoked otoacoustic emissions (CEOAEs) and distortion-product OAEs (DPOAEs) were measured in about 60 rhesus monkeys. CEOAE strength was substantially greater in females than in males, just as in humans. DPOAE strength was generally slightly stronger in females, just as in humans. In males, CEOAEs were weaker (more masculine) in the fall breeding season and in winter than in the summer. In females, CEOAEs were slightly stronger (more feminine) in the fall, when sex steroids are elevated in females (and males), than in the summer when rhesus monkeys are reproductively quiescent. Thus, the sex differences in CEOAEs were greater in the fall than in the summer. We presume that the seasonal fluctuations in OAEs reflect activational hormonal effects, while the basic sex differences in OAEs likely reflect organizational effects of prenatal androgen exposure. Some monkeys of both sexes had been treated with additional testosterone or the anti-androgen flutamide during prenatal development. In accord with expectations, prenatal androgen treatment weakened CEOAEs in females, and prenatal flutamide treatment strengthened CEOAEs in males. For DPOAEs, the differences between treated and untreated groups were mostly small and often inconsistent. Taken as a whole, the data from both rhesus monkeys and humans suggest that the linear, reflection-based mechanism of OAE production that underlies CEOAEs is more sensitive to prenatal androgenic processes than is the nonlinear distortion mechanism that underlies DPOAEs.


Science | 1975

Binaural beats at high frequencies

Dennis McFadden; Edward G. Pasanen

Binaural beats have long been believed to be audible only at low frequencies, but an interaction reminiscent of a binaural beat can sometimes be heard when different two-tone complexes of high frequency are presented to the two ears. The primary requirement is that the frequency separation in the complex at one ear be slightly different from that in the other--that is, that there be a small interaural difference in the envelope periodicities. This finding is in accord with other recent demonstrations that the auditory system is not deaf to interaural time differences at high frequencies.


Journal of the Acoustical Society of America | 1998

Changes in otoacoustic emissions in a transsexual male during treatment with estrogen

Dennis McFadden; Edward G. Pasanen; Narriman Lee Callaway

Otoacoustic emissions (OAEs) were monitored in two human males undergoing estrogen treatment prior to sex-reversal surgery. In one subject, multiple spontaneous emissions (SOAEs) appeared where none had been evident previously. One reasonable interpretation is that (in this male, at least) androgens normally produced a suppressive effect on the cochlear mechanisms responsible for SOAEs, and that the decline in androgen levels produced by the estrogenic drug led to a reduction in that suppression.


Hormones and Behavior | 2006

Masculinized otoacoustic emissions in female spotted hyenas (Crocuta crocuta)

Dennis McFadden; Edward G. Pasanen; Mary L. Weldele; Stephen E. Glickman; Ned J. Place

In humans and rhesus monkeys, click-evoked otoacoustic emissions (CEOAEs) are stronger in females than in males, and there is considerable circumstantial evidence that this sex difference is attributable to the greater exposure to androgens prenatally in males. Because female spotted hyenas are highly androgenized beginning early in prenatal development, we expected an absence of sexual dimorphism in the CEOAEs of this species. The CEOAEs obtained from 9 male and 7 female spotted hyenas confirmed that expectation. The implication is that the marked androgenization to which female spotted hyenas are exposed masculinizes the cochlear mechanism responsible for CEOAEs. The CEOAEs measured in 3 male and 3 female hyenas that had been treated with anti-androgenic agents during prenatal development were stronger than the CEOAEs of the untreated animals, in accord with the implied inverse relationship between prenatal androgen exposure and the strength of the cochlear mechanisms producing CEOAEs. The CEOAEs of three ovariectomized females and two castrated males were essentially the same as those for the untreated females and males, suggesting that there is little or no activational effect of hormones on CEOAE strength in spotted hyenas. Distortion product OAEs (DPOAEs) also were measured. Those sex differences also were generally small (as they are in humans), and the effects of the anti-androgen agents were inconsistent. Thus, prenatal androgen exposure apparently does affect OAEs, but the effects appear to be greater for the reflection-based cochlear mechanism that underlies CEOAEs than for the nonlinear cochlear mechanism underlying DPOAEs.

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Dennis McFadden

University of Texas at Austin

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Kyle P. Walsh

University of Texas at Austin

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Mindy M. Maloney

University of Texas at Austin

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Michelle D. Valero

University of Texas at San Antonio

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Caryn L. Carlson

University of Texas at Austin

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Craig C. Wier

University of Texas at Austin

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David M. Tucker

University of Texas at Austin

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