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Biomedical subjects

M J Raffin

Publications and source records attributed to M J Raffin.

15 recordsLinked to original sources
PubMed1986

Normal performance variability on a dichotic CV test across nine onset-time-asynchrony conditions: application of a binomial-distribution model.

The purpose of the present study was to generate normative data for a dichotic listening task involving the identification of dichotic consonant vowels at interchannel onset-time asynchronies of 120, 90, 60, 30, and 0 msec, under right- and left-lag conditions. The subjects were 30 healthy young adults, all of whom passed rigorous preliminary testing to ensure normal auditory function. Both group and individual data were analyzed. When the data were collapsed across all subjects, the results were similar to those of previous studies. However, the individual data, analyzed according to a model based on the binomial distribution, demonstrated that the collapsed group data were misleading since they did not predict normal variability. Both the group and the individual results suggested that the 90- and 0-msec conditions are the most useful clinically. Further research involving patients afflicted with lesions, in which the data are gathered and analyzed in a manner similar to that of the present study, was recommended.

Adult↗
PubMed1985

Reliability of threshold, slope, and PB max for monosyllabic words.

The Auditec recordings of the CID W-22 monosyllables were used to generate test and retest intelligibility functions on normally hearing listeners and subjects with mild-to-moderate sensorineural hearing loss. The normally hearing subjects were tested with 50-word lists at SPLs ranging from 15 to 50 dB. Lists of 25 words were used with the hearing-impaired group. The functions were analyzed to assess the reliability of threshold (50% point), slope (20%-80% points), and maximum intelligibility (PB max). The 50% point was obtained at 28 dB SPL for the normally hearing listeners and at a sensation level (SL) of 12 dB respondaic thresholds for the hearing-impaired group. Very stable monosyllabic thresholds were found because 95% of the test-retest values were within 6 dB for both subject groups. Slopes of 4.9% per dB and 2.7% per dB were obtained for the normally hearing and hearing-impaired groups, respectively. Fair reliability was observed; 95% of the test-retest values encompassed a range of +/- 1.9% per dB for the normally hearing subjects and +/- 1.1% per dB for the hearing-impaired group. Although group slopes provide useful information for selecting the range and step size for generating psychometric functions, the value of routinely obtaining slope on an individual basis has not been demonstrated. Even though the same word lists were used for both test and retest measurements, reliability closely agreed with predicted results based on the binomial theorem. In contrast to the large variability for a single list of 25 words, very stable PB max scores were found when two or three scores were averaged on the plateau of the function.

Adult↗
PubMed1983

Assessment of electromagnetic characteristics of the Willeford Central Auditory Processing Test Battery.

Electromagnetic characteristics of eight tape recordings of the Willeford Central Auditory Processing Test Battery were assessed. Measurements indicate that when recording levels are referenced to the calibration tone preceding a given subtest of that battery, significant intertape differences, interest differences, and interchannel differences in the recording levels of test items exist. Mean recording levels of items used in the Rapidly Alternating Speech Perception, Low-Pass Filtered Speech, and Competing Sentences subtests typically were within 10 dB of the reference tone. Recording levels for the Binaural Fusion subtest yielded intertape differences of as much as 26.5 dB. Given the large intertape inconsistencies in recording levels, extreme caution should be exercised in the use of these recordings.

Auditory Perceptual Disorders↗
PubMed1982

Cost effectiveness of various spondee-threshold methods.

Spondees (N:15) chosen from the literature as having relatively homogeneous intelligibility were re-recorded to preserve this feature. ST's were collected twice from 60 normal-hearing young adults by each of 6 combinations of method (ascending, descending, bracketing) and step size (2-, 5-db). A cost-benefit analysis (test-retest reliability, time required, agreement with PTA) yielded the descending-2-db combination as superior to other combinations.

Adult↗
PubMed1982

Effects of extended-range frequency-response amplification in hearing aids.

Spondaic threshold (ST), loudness-discomfort level (LDL) for speech-shaped noise, and NU6 speech scores at 50 db HL (in quiet and at S/N = 0) were taken from 8 adults aged 34-80 yrs, with HTLs less than or equal to 20 db at .25-1 kc/s but with moderate-to-severe sensorineural hearing impairments beginning above 1 kc/s. S listened monaurally to a loudspeaker in an audiometric booth wearing no hearing aid in the test ear or one of 2 all-in-the-ear aids differing only in frequency response (.38-5 kc/s vs .30-7 kc/s). Gain was not changed during the experiment. Extended-range amplification for the total group was not beneficial, nor was it found generally beneficial even when speech scores in quiet or in noise for a group of 4 Ss with impairments beginning above 2 kc/s were compared with those for a group of 4 Ss with impairment beginning below 2 kc/s. However, the narrower-band aid revealed significant (0.10 level of confidence) amplification effects on speech scores compared with the unaided condition.

Acoustics↗
PubMed1982

Incidence of hearing loss among geriatric nursing-home residents.

Of 285 residents in 4 Montana nursing homes, pure-tone ac HTLs were collected on 259 ears of 151 Ss, aged 54-95 yrs (mn: 80.6 yrs) who were able and willing to participate. Only 6% of ears were normal [PTA (.5, 1, 2 kc/s) less than 25 db], 11% had mild losses (25-45 db), 13% had moderate (45-65 db), 35% had high-frequency slope beginning at 2 kc/s, and 35% had severe or profound losses (greater than 65 db). Of 175 ears of 92 Ss completing tympanometry, 85% had normal peak-pressure points, 9% were mildly positive/negative, and 7% were abnormal. Of 116 ears from 62 Ss completing contralateral acoustic reflex study, only 58% exhibited reflexes. Of 59 ears from 34 Ss completing ipsilateral acoustic reflex study, only 39% exhibited reflexes. 48% of ears exhibited abnormal otoscopic findings. Only 17 Ss reported owning a hearing aid (though for half the Ss Medicaid allowed payment for such aids). Of 13 aids actually inspected, all were malfunctioning in correctable ways. Audiological referrals were made for 94% of the 151 Ss, and medical referrals for 58%. These data corroborate other studies on the low status of audiological services in such populations.

Aged↗
PubMed1980

Use of common morphemes by hearing-impaired children exposed to a system of manual English.

Severely hearing-impaired children (11 boys, 9 girls), whose educational procedures included the use of Seeing Essential English (SEE) were given an experimental task designed to test their use of 8 common inflectional morphemes: plural /s/, possessive /s/, present tense singular /s/, past tense /ed/, present progressive /ing/, adjectival and adverbial /ly/, comparative /er/, and superlative /est/. Each child read 20 sentences composed of primer and first grade level words, and circled 1 of 4 word choices to fill in a missing word in each sentence. All 4 word choices had the same root. Responses were analyzed relative to chronological age, sex, degree of hearing loss, duration of exposure to SEE, reading level, and consistency of teacher usage of SEE. Performance appeared to be most dependent on sex, reading level, and teacher consistency. Although these factors were confounded, results indicate that teacher consistency in usage of SEE may be the major determiner of performance on the task.

Age Factors↗
PubMed1978

Comprehension of inflectional morphemes by deaf children exposed to a visual English sign system.

A test of morpheme-based concepts was administered to 67 deaf children who were exposed to Seeing Essential English (SEE). Results indicated that these children show the following order of acquisition for the inflectional morphemes tested: plural -s, past tense -ed, present progressive -ing, possessive -'s, third person present indicative -s, comparative -er, superlative -est, and present perfect -en. There were no effects of sex, age, or school from which the subjects were selected. The main contribution to the subjects' performances were their lengths of exposure to SEE.

Age Factors↗
PubMed1978

Speech-discrimination scores modeled as a binomial variable.

Many studies have reported variability data for tests of speech discrimination, and the disparate results of these studies have not been given a simple explanation. Arguments over the relative merits of 25- vs 50-word tests have ignored the basic mathematical properties inherent in the use of percentage scores. The present study models performance on clinical tests of speech discrimination as a binomial variable. A binomial model was developed, and some of its characteristics were tested against data from 4120 scores obtained on the CID Auditory Test W-22. A table for determining significant deviations between scores was generated and compared to observed differences in half-list scores for the W-22 tests. Good agreement was found between predicted and observed values. Implications of the binomial characteristics of speech-discrimination scores are discussed.

Humans↗
PubMed1976

Time-intensity trade for speech: a temporal speech-Stenger effect.

Time-intensity trade for selected spondaically stressed words was investigated using a centering method for interaural time delays of 0.00, 1.00, 2.00, 2.25, 2.50, and 2.75 msec at five levels of presentation: 0-, 25-, 40-, 55-, AND 70-DB HL (ANSI, 1969). Lateralization effects increased with level of presentation, with a maximum lateralization effect of between 22 and 30 dB occuring with an interaural time delay of 2.25 msec. Multiple images were perceived by all subjects with an interaural time delay of 2.75 msec and by some subjects with an interaural time delay of 2.50 msec at high levels of presentation. No "ear effect" was observed for any of the listeners. A potential clinical application is discussed for this temporal speech-Stenger effect.

Adult↗