Biomedical subjects

H Levitt

Publications and source records attributed to H Levitt.

At least 73 records · Page 4Linked to original sources

PubMed1978

Speech and language assessment scales of deaf children.

Six year old deaf children with an average PTA of 105.7 dB were evaluated for speech and language skills using rating scales. Five rating scales were designed to assess language production, sign ability, overall communication skills, speech reception and speech intelligibility. Each scale incorporated five categories ranging from inability to complete ability to demonstrate a given skill. For several ratings, classroom teachers, given instruction, were asked to make judgments which were later correlated with examiner's scores, Mean ratings indicate that comprehension skills superceded performance skills. A hierarchy of ability among communication skills can be seen.

Auditory Perception↗

PubMed1978

The effect of selected prosodic errors on the intelligibility of deaf speech.

A trained speech pathologist listened to recordings of 40 deaf children, each reading 15 sentences and recorded instances of four types of prosodic errors: adventitious sounds, excessive phoneme duration, pitch breaks, and pauses. The scores were correlated with previously obtained intelligibility scores. It was found that adventitious sounds, except those obviously operating as transitional sounds to ease the movement from one place of articulation to another, had the greatest negative effect on intelligibility, followed by very long duration and pitch breaks. Medium and long pauses, long duration, prologned closure (i.e., long duration plosives), and adventitious transitional sounds had a lesser negative effect. Short pauses had a small positive effect on intelligibility. The method used to identify the errors was one that can hopefully be evolved into an evaluative instrument for practical use in schools for the deaf.

Adolescent↗

PubMed1978

Computer-assisted analysis of written language: assessing the written language of deaf children.

Methods for assessing the written language of deaf students are reviewed. The merits and shortcomings of various objective indicators that have traditionally been used are discussed. These include various measures of total output, such as total number of words or sentences, and simple measures of diversity of usage such as the type-token ratio. There have been several attempts in recent years to include objective measures of syntactic complexity as part of an overall language assessment program. The use of a computer to assist teachers in the derivation of such syntactic measures is described. Two illustrative examples are provided. The first shows how the computer system performs a detailed syntactic analysis on a typical sentence taken from the written language of a deaf child. The second example shows how the system provides a summary analysis of several sentences in a theme. A statistical count of the syntactic forms used in the written language sample is provided at the end of the analysis.

Adolescent↗

PubMed1978

Computer applications in clinical training.

Computer-based systems for enhancement of clinical training in audiology and speech pathology are described. The method employed places students in the position of having to make the kinds of critical observations and diagnostic judgments that typically occur in a clinical setting. The role of the computer is to simulate diagnostic tests, with or without patient variability, or to control a series of videotapes that depict various aspects of clinical practice. The systems described in this article are intended to augment conventional training procedures and should be used in conjunction with the student's coursework and regular clinical practicums.

Audiology↗

PubMed1978

The evaluation of a model speech training program for deaf children.

Systematic speech training procedures were employed with a group of 20 hearing-impaired children ranging in age from 7 to 10 years. Using a primarily auditory-oral approach, the speech training program employed a hierarchical sequence in order to teach the suprasegmental patterns of English to the children. The children's performance on the speech training hierarchy was monitored on a daily basis using a checklist system. Based on their rate of progress in the development of speech skills, the children were divided into three groups post hoc: rapid, slow but steady, inordinately slow. Although the system worked well, on the average, approximately one-third of the children encountered serious difficulites at one or more levels of the hierarchy. Examination of the children's background information and audiological data revealed that those children who encountered difficulty had an extremely limited amount of residual hearing and/or problems other than a hearing handicap.

Child↗

PubMed1978

Speech reception by the hearing-impaired: methods of testing and the development of new tests.

The development of tests for measuring speech reception in the hearing impaired is reviewed. The rationale for a new closed-response-set nonsensesyllable test is presented followed by a description of the test. Preliminary normative and comparative data for this Nonsense Syllable Test are reported. Current work on the development of related tests for young, profoundly deaf children, and measuring reception of the prosodic features of speech is also described.

Audiometry, Speech↗

PubMed1978

Methods for the evaluation of hearing aids.

Methods of hearing-aid evaluation are sub-divided into four broad categories, prescriptive selective amplification, selection from a set of existing hearing aids, use of a fixed frequency-gain characteristic, and adaptive fitting of a master hearing aid. The advantages, disadvantages, and controversies associated with each approach are reviewed and major research needs are discussed in the light of this review. Among the more important research needs are i) the development of improved speech tests that have low test-retest variability and which can discriminate between hearing aids with much greater precision than existing tests, ii) the development of reliable methods of predicting hearing-aid performance from audiological data, and iii) the determination of the optimum characteristics of the simplest, conventional hearing aid (i.e., a frequency-selective linear amplifier with no distortion other than peak clipping to limit maximum power output). It is also recommended that the simplest conventional hearing aid with gain, frequency-response, and clipping characteristics optimally matched to the subject's residual hearing be used as a reference for assessing more sophisticated hearing aids or alternative auditory prostheses for the hearing impaired. The third part of the paper provides a progress report on the development of a protocol for the prescriptive fitting of a wearable master hearing aid. The results to date show that the parameters of a conventional hearing aid can be adjusted according to well established optimization procedures so as to obtain superior, if not optimum, performance for each subject as a result of such individualized adjustments.

Acoustics↗

PubMed1978

Adaptive testing in audiology.

A general approach to adaptive testing of the up-down type is described. Audiological applications of the procedure are described, including measurement of the auditory threshold, estimating the spread of the subject's response curve, testing for sequential response dependencies, and finding PB-max. Guidelines are provided for the practical implementation of these procedures using relatively simple rules for controlling stimulus levels and for estimating the parameters of interest. Also described is the Simplical Method, a multivariate adaptive procedure which, like the transformed up-down method, is relatively efficient yet involves simple rules of adjustment and of estimation. The Simplical Method has been used in the adaptive fitting of a wearable master hearing aid and an example of this application is given.

Audiometry↗

PubMed1978

Backward and forward masking with reproducible noise bursts.

This study investigated the effects of two "frozen" narrow-band waveforms with different waveform envelopes 50 msec in duration and centered at 250 Hz, on temporal masking at short masking intervals and, further, assessed the effects of phase shifts on backward and forward masking. Four normal-hearing experienced Ss detected a monaurally presented 250-Hz tone burst, 12 msec in duration, that either preceded, occurred simultaneously with, or followed a burst of the narrow-band noise. A 2IFC technique was used with a transformed up-down procedure for threshold estimation. The masking intervals from onset of masker to onset of tonal pulse ranged from -30 to +70 msec. The 3 phasic conditions for the signal were in-phase, 90 degrees out-of-phase, and 180 degrees out-of-phase. Results of this experiment substantiated the data of other researchers who have shown greater backward than forward masking at short masking intervals and greater masking was found for all simultaneous conditions than for any of the backward or forward masking conditions. In addition, differences between the two noise waveforms, as well as the phase shifts, had a significant effect on the thresholds obtained for the backward and forward masking conditions, as well as for the simultaneous masking conditions. Criterion change and waveform storage are discussed as possibly having an effect up these variables.

Acoustic Stimulation↗

PubMed1976

Age-related decrement in hearing for speech. Sampling and longitudinal studies.

A 10-year study was conducted in which 282 adults in age decades of 20 through 80 were tested in a comprehensive battery of tasks requiring the perception of speech under a variety of conditions in which the speech signal was degraded. The original results were plotted to reveal the differences in performance of the population samples of each decade. In follow-up studies, after 3 years and again after 7 years, samples of the original subject population were retested. The results of the first, stratified sampling and of the longitudinal studies are compared. The two most apparent trends are: (1) the perception of degraded (distorted and competed) speech undergoes a noticeable decline beginning with the 5th decade of life, and (2) the decline is sharply steeper in the 7th decade.

Adolescent↗

PubMed1975