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Biomedical subjects

W Waugh

Publications and source records attributed to W Waugh.

10 recordsLinked to original sources

Dynamic auditory localization: systematic replication of the auditory velocity function.

Two experiments explored the capability of normal-hearing adults to judge the apparent velocity of an unseen moving sound source. In exper. I, 9 naive and, 1 experienced S judged the velocity of a moving source emitting a .5-kc/s tone at 50 db SPL. S's head was in the center of a circle of 1.88-m radius swept by a small loudspeaker. In exper. II the sound was a low-pass-filtered (0.1-1 kc/s) noise at 50 db sound spectrum level. In both experiments perceived velocity was directly proportional to the actual velocity of the source. These results support out initial observations (Waugh et al, J. Aud. Res., 1979, 19, 103-1 10) that auditory velocity discrimination can be described as a power function with an exponent of 1.0. In exper. II the Ss also varied the sound source velocity by means of a variable resistor to produce a perceived velocity of 100 degrees/sec. Performance on the adaptive velocity production task was successfully predicted from the data of the absolute velocity judgment task. The Weber fraction was .052 for relatively fast-moving sound sources (100 degrees/sec). The ability to discriminate sound source velocity appears to be a well-defined feature of the dynamic binaural spatial system.

Audiometry

Perception of moving sounds: velocity discrimination.

Two experiments investigated auditory velocity perception. Exper. I compared auditory to visual velocity estimates. Five adults judged, in miles/hr, the motion of a sound source (a small loudspeaker) moving on a 1.88-m boom around S's head at each of 7 velocities from 15 to 360 degrees/sec. The sound source was either visible or not visible. Velocity judgments were shown in both modalities to be a power function of source velocity, with a slope of approximately 0.90. No significant difference was found between the auditory and visual functions. A control Exper. II determined with 14 naive adults that the similarities between the functions in each modality could not be attributed to either previous visual experience or proprioceptive feedback. Ss estimated the velocity of the visible moving loudspeaker while tracking the source with their eyes (N: 7) or while fixating on a small stationary light (N: 7). Eye motion was recorded from electrodes on the canthi. No significant differences were found between these conditions. The estimates were again shown to be a power function of source velocity (though slightly higher slopes of 0.99 for visual pursuit and 1.0 for visual fixation were obtained than in Exper. I). These experiments suggest a surprising degree of similarity in the perception of velocity in auditory and visual spatial functions.

Adult

A method for self-assessment of disability before and after hip replacement operations.

A standardised form was developed to review the daily problems suffered by patients with arthritis of the hip and provide clinicians with information for planning treatment and in judging subsequent progress. The reports made by various patients in a preliminary study provided 81 statements on pain, restricted movements, and restricted activities that were then tested to identify the most reliable. The responses of 32 patients waiting for hip replacements and 66 patients who had undergone operation were compared with independent assessments of pain and physical limitations. The 33 statements eventually selected were chosen mainly on the basis of their sensitivity to differences between preoperative and postoperative patients and their correlation with the independent assessments. The final questionnaire provides a valid and concise summary of a patient's disabilities and is simple enough for the patient to complete while waiting to see the doctor.

Aged

The use of footprints in assessing the results of operations for hallux valgus. A comparison of Keller's operation and arthrodesis.

One hundred and seventy feet have been reviewed after operations for hallux valgus; eighty-five had had arthrodesis of the first metatarso-phalangeal joint and eighty-five had had Keller's operation. Footprints were made in order to assess the patterns of weight-bearing on the big toe and on the lesser metatarsal heads. After arthodesis the big toe bore weight in 80 per cent compared with 40 per cent after Keller's operation. The ability to bear weight on the big toe is related to the presence of metatarsalgia and excessive weight-bearing on the lesser metatarsal heads. These complicaitons were seen more commonly after Keller's operation (particularly when more than one-third of the phalanx had been excised) than after arthrodesis.

Arthrodesis