Search PubMed⌕ Search

Biomedical subjects

M P Gelfer

Publications and source records attributed to M P Gelfer.

12 recordsLinked to original sources
PubMed2000

Comparison of acoustic and perceptual measures of voice in male-to-female transsexuals perceived as female versus those perceived as male.

The present study explored significant differences between male-to-female transgendered speakers perceived as male and those perceived as female in terms of speaking fundamental frequency (SFF) and its variability, vowel formants for /a/ and /i/, and intonation measures. Fifteen individuals who identified themselves as male-to-female transsexuals served as speaker subjects, in addition to 6 biological female control subjects and 3 biological male control subjects. Each subject was recorded reading the Rainbow Passage and producing the isolated vowels /a/ and /i/. Twenty undergraduate psychology students served as listeners. Results indicated that subjects perceived as female had a higher mean SFF and higher upper limit of SFF than subjects perceived as male. A significant correlation between upper limit of SFF and ratings of femininity was achieved.

Adult↗
PubMed1999

Near-field speech intelligibility in chemical-biological warfare masks.

It is common knowledge among field personnel that poor speech intelligibility can occur when chemical-biological warfare (CBW) masks are worn: indeed, many users resort to hand signals for person-to-person communicative purposes. This study was conducted in an effort to generate basic information about the problem; its focus was on the assessment of, and comparisons among, the communicative efficiency of seven different CBW units. Near-field word intelligibility was assessed by use of rhyming minimal contrast tests; user and acoustic restrictions were studied by means of diadochokinetic tests and system frequency response. The near-field word intelligibility of six American-designed masks varied somewhat, but overall it was reasonably good; however, a Russian unit did not perform well. Second, three of the U.S. masks were found to produce less physiological restraint than the others, and the Soviet mask produced the greatest physiological restraint. Finally, a few of the CBW masks also exhibited very low levels of acoustic distortion. Accordingly, it was concluded that two of the several configurations studied exhibited superior features. Other factors being equal, they can be recommended for field use and as a basis for the development of future generations of CBW masks. However, it also should be noted that although these devices provided reasonably good speech intelligibility when the listener was close to the talker, they do not appear to do so even at minimal distances.

Adult↗
PubMed1997

Comparisons of intensity measures and their stability in male and female speakers.

The purpose of the present study was to provide data on the intensity characteristics of young adult speakers in terms of conversational intensity level, conversational intensity range, and available intensity range. Subjects included 20 males and 20 females, ages 20-30 years. Each subject was asked to read the Rainbow Passage at a conversational intensity level, as softly as possible without whispering, and as loudly as possible, on 2 separate days 1 week apart. The second and third sentences of the three readings on both days were analyzed for various intensity parameters. Results revealed a conversational intensity level of 70.42 dB for males and 68.15 dB for females. When male and female intensity measures were compared, few statistically significant differences were found. Further, when intensity measures for the first and second readings were compared, few significant differences were found.

Adult↗
PubMed1996

Documenting laryngeal change following prolonged loud reading. A videostroboscopic study.

This study investigated the effects of prolonged loud reading on trained and untrained subjects. Subjects were eight young women singers, and eight young women with limited musical experience. Each subject underwent videostroboscopic examination prior to and following 1 h of prolonged loud reading. The pretest and posttest videotaped samples were randomized and presented to three experienced judges, who evaluated various aspects of laryngeal appearance and vibratory characteristics. Analyses of group data revealed that untrained subjects showed a small but significant increase in amplitude of vocal fold excursion following the experimental task. No significant differences were noted in the trained singer group. When individual variation was analyzed, it was found that most subjects did not show many changes from pretest to posttest. It was concluded that a l-h loud-reading task was not sufficient to induce notable laryngeal alterations.

Adult↗
PubMed1995

Comparisons of jitter, shimmer, and signal-to-noise ratio from directly digitized versus taped voice samples.

The purpose of this study was to compare jitter, shimmer, and signal-to-noise ratio (SNR) measures obtained from tape-recorded samples with the same measures made on directly digitized voice samples, with use of the CSpeech acoustic analysis program. Subjects included 30 young women who phonated the vowel /a/ at a comfortable pitch and loudness level. Voice samples were simultaneously recorded and digitized, and the resulting perturbation measures for the two conditions were compared. Results indicated that there were small but statistically significant differences between percent jitter, percent shimmer, and SNR calculated from taped samples compared with the same measures calculated from directly digitized samples. It was concluded that direct digitization for clinical measures of vocal perturbation was most desirable, but that taped samples could be used, if necessary, with some caution.

Adult↗
PubMed1995

Fundamental frequency, intensity, and vowel selection: effects on measures of phonatory stability.

Measures of phonatory stability such as jitter, shimmer, and signal-to-noise ratio (SNR) are increasingly used in clinics and laboratories, yet questions about the effects of various aspects of voice production on these acoustic variables have received only limited attention. The purpose of the present study was to examine the effects of frequency, intensity, and vowel selection on those measures of phonatory stability. Twenty-nine young adult females were used as subjects. Each subject produced vocalizations at her speaking fundamental frequency (SFF) and one octave above SFF; at 60, 70, and 80 dB; and on the vowels /i/ and /a/, for a total of 12 vocalizations per subject. These vocalizations were then analyzed, using CSpeech acoustic analysis software, to obtain measures of jitter, shimmer, and SNR. Results revealed that frequency, intensity, and vowel selection all affected various phonatory stability measures, with the highest perturbation values almost always occurring in the low frequency-low intensity condition. Implications and physiological explanations for the results of the study were presented.

Adult↗
PubMed1993

A multidimensional scaling study of voice quality in females.

In this study, a multidimensional scaling (MDS) analysis was performed to investigate perceptual discrimination by listeners among normal female voices. Speech pathologists and untrained listeners rated the similarity of all possible pairings of 20 female voices presented in sentences. MDS analyses were performed on these data. To interpret the resulting dimensions, listeners additionally evaluated each voice on each of 17 rating scales. For each listener group, the normalized and averaged perceptual ratings were correlated with MDS stimulus coordinates for the 20 voices. This procedure resulted in a five-dimensional solution which best explained the speech pathologists' similarity-dissimilarity judgements, with the following perceptual correlates for each dimension: (1) perceived pitch, (2) perceived loudness, (3) perceived age and duration of the speakers' stimulus sentence, (4) perceived variability, and (5) perceived quality. The untrained listeners' judgements were best explained by a two-dimensional solution. Comparisons with other MDS studies were made, and the need for new acoustic measures was discussed.

Adult↗
PubMed1991

Listening preferences for voice types as a function of age.

This experiment was designed primarily to generate information about the preferences of older listeners for various classes of voices. Speech samples for that purpose were elicited from 80 speakers, who provided the desired stimuli (sentences) under frequency and intensity control. Specifically, there were eight cells in the design, each represented by 10 speakers (5 male and 5 female); all combinations of low, medium, and high speaker fundamental frequency (SFF) were combined with soft, middle and loud vocal intensity (VI) productions--except for the low-SFF/high-VI combination, which proved impossible to obtain. Listeners were four groups of 20 individuals equally divided as to sex. The two older of these groups, designated as the experimental subjects, were: older adults (60-70 years of age) and the elderly (80-90 years). The two younger groups served as controls; they included young adults (20-30 years of age) and middle-aged adults (aged 40-50 years). Listeners rated each speech sample on a 5-point preference scale varying from "like very much" to "dislike very much." The results suggest that most listeners prefer medium intensity voices. Other preference tendencies were toward low-pitched voices and (slightly) toward male speakers; but these trends were not as marked as the first. Most importantly, there were no systematic differences in voice type preferences between or among the older and younger groups--or between male and female listeners.

Adult↗
PubMed1989

Stability in phonational frequency range.

The purpose of the present study was to investigate the stability of total phonational frequency range, and the stability of the elements from which it is calculated--lowest fundamental frequency and highest fundamental frequency--both within a single day and over a prolonged period. Twenty adult subjects were instructed to produce vowel vocalizations at the extremes of their frequency ranges. Lowest and highest frequencies were converted to semitones, and total range in semitones was calculated. Data were collected three times per day for two days 1-2 months apart. Results revealed that for the average subject, all measures varied by at least several semitones. Further research is needed in order to determine the sources of this intrasubject variability before these measures can be applied to clinical populations.

Adult↗
PubMed1983

Criminal identification comparison: aural versus visual identifications resulting from a simulated crime.

This research was undertaken to investigate and contrast visual and aural/perceptual identifications of a previously unknown individual from a set of photographic and tape-recorded exemplars following a simulated crime. All participants were volunteers for the "criminal," the victim of an "assault," and all suspects drawn from a Reserve Officer Training Corps (ROTC) class; the "witnesses" were 61 students in a law class. The student/witnesses were divided into four groups. Group A made three identifications (serially) one day, one week, and two weeks after the crime took place. Group B saw the photographs and heard the tapes only once a week after the incident, and Group C only after two weeks had elapsed. Witnesses in a fourth group (D) followed the same schedule as did Group A; however, they were presented with foils similar in appearance and speech to the criminal. Group D was presented both the foil and criminal in the photographic lineup at the final judging session. The results demonstrated that visual identification can be quite accurate although not consistently or predictably so. By contrast, aural/perceptual identifications were relatively poor. No strong trends for latencies were observed, either for repeated trials or for procedures involving different initiation latencies; nor did confidence levels appear to be related to accuracy of judgment. Finally, when a similar looking foil was included in the identification task, there was a weak trend for the foil to be chosen more often in subsequent trials. These results support the position that eyewitness--and especially earwitness--testimony should be viewed by judges and juries with greater caution than has been the case in the past; by appropriate instructions, juries should be given assistance in interpreting and in assigning appropriate weight to this kind of testimony.

Adult↗