Biomedical subjects

B J May

Publications and source records attributed to B J May.

8 recordsLinked to original sources

PubMed1992

Pinna-based spectral cues for sound localization in cat.

The directional dependence of the transfer function from free field plane waves to a point near the tympanic membrane (TM) was measured in anesthetized domestic cats. A probe tube microphone was placed approximately 3 mm from the TM from beneath the head in order to keep the pinna intact. Transfer functions were computed as the ratio of the spectrum of a click recorded near the TM to the spectrum of the click in freefield. We analyze the transfer functions in three frequency ranges: low frequencies (less than 5 kHz) where interaural level differences vary smoothly with azimuth; midfrequencies (5-18 kHz) where a prominent spectral notch is observed; and high frequencies (greater than 18 kHz) where the transfer functions vary greatly with source location. Because no two source directions produce the same transfer function, the spectrum of a broadband sound at the TM could serve as a sound localization cue for both elevation and azimuth. In particular, we show that source direction is uniquely determined, for source directions in front of the cat, from the frequencies of the midfrequency spectral notches in the two ears. The validity of the transfer functions as measures of the acoustic input to the auditory system is considered in terms of models of sound propagation in the ear canal.

Acoustic Stimulation↗

PubMed1992

Dynamic range of neural rate responses in the ventral cochlear nucleus of awake cats.

1. Response thresholds and dynamic range properties of neurons in the ventral cochlear nucleus (VCN) of awake cats were measured by fitting a computational model to rate-level functions for best frequency (BF) tone bursts and for bursts of broad-band noise. Dynamic range measurements were performed in quiet and in the presence of continuous background noise. 2. The sample of neurons obtained in the VCN of awake cats exhibited a variety of peristimulus histograms (PSTHs) and thresholds. All PSTH response types previously described in the VCN of anesthetized cats were found in awake cats. The lowest thresholds for neural responses were observed at sound pressure levels that were equivalent to behavioral thresholds of absolute auditory sensitivity. 3. When responses to BF tones or bursts of broad-band noise were recorded in quiet backgrounds, the dynamic range properties of most units in the VCN of awake cats were not significantly different from dynamic range properties of auditory nerve fibers (ANFs) in anesthetized cats or VCN units in decerebrate cats. All auditory units showed a larger dynamic range for noise bursts than for tone bursts, but VCN units with primary-like and onset PSTHs showed larger dynamic ranges for responses to noise bursts than that of ANFs and VCN chopper units. 4. When tests were performed in the presence of continuous noise, rate-level functions for BF tone bursts shifted to higher tone levels and showed a more compressed range of driven rates in comparison with data obtained in quiet. Compression of the rate-level function in noise resulted from an increase in driven rate at low tone levels and a decrease in rate at high tone levels. These changes in the rate-level function suggest that noise may reduce the range of BF tone levels that are potentially encoded by a unit's rate responses. By exhibiting larger shifts and less compression in background noise, VCN units in awake cats better preserved the dynamic range of their rate responses to BF tones than ANFs in anesthetized cats or VCN units in decerebrate cats. 5. Rate-level functions were obtained from a small sample of VCN units not only with the cat performing the behavioral task but also with the cat awake and sitting quietly in the testing apparatus. No differences in noise-induced shift or compression were noted between the two testing conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Acoustic Stimulation↗

PubMed1991

Single-unit recording in the ventral cochlear nucleus of behaving cats.

A method is described for single-unit recording in the ventral cochlear nucleus (VCN) of behaving cats. Five cats were implanted with titanium head-restraint devices and acetal plastic recording chambers. The recording chamber directed microelectrodes through the cerebellum and into the VCN. Electrophysiological recordings were obtained from isolated VCN units while the cats engaged in an auditory discrimination task. The task required the cats to discriminate changes in the temporal pattern of a series of tone or noise bursts. Cats initiated the testing sequence by depressing a lever, and obtained food by releasing the lever when the pattern of stimuli changed from one 200-ms burst/s to four 50-ms bursts/s. Stimulus features (i.e., frequency, level, duration) were manipulated to characterize the physiological responses of VCN units. Preliminary data suggest that peri-stimulus time histograms (PSTHs) and rate-level functions (RALVs) obtained from behaving cats are similar to those previously described in anesthetized and decerebrate cats when units are tested with tones in quiet backgrounds. However, in comparison to anesthetized and decerebrate cats, units obtained in behaving cats demonstrate a more sensitive rate representation of stimulus level when tested in continuous background noise.

Acoustic Stimulation↗

PubMed1991

Expert decision making in physical therapy--a survey of practitioners.

Four hundred American and 384 Australian physical therapists, nominated by their peers as expert clinicians, were studied to evaluate whether a particular cognitive style was prevalent among expert clinicians, to identify preferred sources of information for clinical decision making, and to determine the similarities and differences between American and Australian therapists. Results were based on usable survey responses from 348 American and 290 Australian therapists. Eighty-eight percent of the American therapists and 82% of the Australian therapists identified themselves as working primarily in general practice, orthopedics, or neurology. The physical therapy assessment and interviews with the patient were the preferred sources of information in both countries. The physician's referral and communications with other health care personnel were reported to be of limited value as sources of information by most respondents. Overall, both groups responded most positively to the receptive style of data gathering and the systematic style of information processing. Therapists working primarily with neurologically impaired patients responded most positively to the preceptive style of data gathering and the intuitive style of information processing. Therapists working primarily with patients with orthopedic disorders responded most positively to the systematic style of information processing.

Attitude of Health Personnel↗

PubMed1978

A statewide amputee rehabilitation programme.

Patients are referred to the amputee clinic at the Medical College of Georgia from all areas of the State of Georgia. Most referrals are made a considerable time after amputation and most patients live from 50 to 250 miles from the amputee clinic. A special programme was designed to alleviate some of the problems incurred by the distance and the delayed referral. Physical therapists, prosthetists, social workers, the vocational counsellor and the orthopaedic surgeon co-operate to provide maximum care on the day of the amputee clinic. The cooperative efforts of all members of the team and the ability to plan ahead for optimum rehabilitation maximize the use of patients' time and his rehabilitation level.

Amputees↗

PubMed1977

Evaluation in a competency-based educational system.

Competency-based curricula have been implemented at the Medical College of Georgia to prepare students to meet entry level competencies as physical therapists and physical therapist assistants. Criteria-referenced evaluations are used to determine if students have achieved the desired competencies. Performance is measured against the criteria and not other students. The process of developing the system currently in use at the Medical College of Georgia is delineated in some detail and some of the advantages of the system for physical therapy education are discussed.

Achievement↗

PubMed1977

An integrated problem-solving curriculum design for physical therapy education.

Development of and experience with an integrated problem-solving curriculum design for physical therapy education is presented. The basic themes which relate discrete subject areas and a method of organizing the content around the themes are described. Problem-solving learning experiences are sequenced from the simple to the complex around the kind of situations found in clinical practice. Clinical education is integrated throughout the curriculum, and a calendar is developed based on the content of the learning experiences rather than the traditional university calendar.

Curriculum↗

PubMed1976

Time unit system of fee setting.

An efficient, accurate, and simple method was developed to determine charges for physical therapy services. Based on cost accounting, the charges were developed from the direct and indirect costs of operating the department. Methods to determine operating costs are outlined and the process used to establish a time unit system is presented. The charges to the patient were developed to reflect accurately the patient's use of resources in terms of time, supplies, and share of indirect costs. A differentiation was made between direct treatment time when the patient is in actual contact with a physical therapist or physical therapist assistant and nondirect time when the patient is practicing a skill on his own. Although developed for a medical center teaching hospital, this system can be adapted to any type of facility.

Cost-Benefit Analysis↗