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Biomedical subjects

H Kaplan

Publications and source records attributed to H Kaplan.

270 records · Page 15Linked to original sources
PubMedDate not supplied

The acoustic reflex in children without an hermetic seal.

In clinical practice with children, the hermetic seal is either often not obtainable or is lost before acoustic reflex measures are obtained. In a recent study, Surr and Schuchman (Archives of Otolaryngology 102, 160--161, 1976.) found that in the majority of cases reflex thresholds could be measured in adults with normal middle ears in the absence of an hermetic seal. This study was designed to find out whether the conclusions of Surr and Schuchman could be extended to children. Sealed and unsealed reflexes were compared in 30 children, ages 3 to 7, with normal middle ears. Results indicated that: (1) approximately two-thirds of the children demonstrated reflexes in the unsealed condition; (2) differences between sealed and unsealed reflex thresholds were not clinically significant; (3) in most cases, unsealed reflexes were measurable at all frequencies or at none; (4) neither size of ear canal volume nor amplitude of the sealed reflex at 10 dB SL seemed to be related to the presence or absence of the unsealed reflex. It was concluded that reflex thresholds obtained in the absence of an hermetic seal may be considered valid but the absence of an unsealed reflex should not be considered diagnostically significant.

Acoustic Impedance Tests↗
PubMedDate not supplied

Effects of dichotic/diotic versus monotic presentation on speech understanding in noise in elderly hearing-impaired listeners.

Hearing-impaired elderly subjects with mild to moderate, bilaterally symmetrical, sensorineural hearing losses received speech stimuli mixed with cafeteria and speech-babble noises in a variety of listening conditions. Open and closed set Rhyme test words and Speech Perception in Noise test sentences were presented at individually determined signal-to-noise ratios. the listening conditions included: (1) monotic against which all other conditions were compared; (2) low frequency attenuation of 5, 10, and 15 dB relative to the high frequencies; (3) dichotic, with the frequency band above 1000 Hz presented to the preferred ear and the band below 1000 Hz to the other ear; and (4) diotic, with identical speech-in-noise signals presented simultaneously to both ears. Results indicated: (1) regardless of type of stimulus, open or closed set presentation, or type of noise, most of the dichotic and/or diotic presentations were superior to monotic at 0.05 or 0.01 significance levels; (2) under most conditions, dichotic/diotic conditions were superior to the low frequency attenuated presentations; (3) subjects with abnormal Synthetic Sentence Inventory functions seemed to use dichotic/diotic input as well as those with normal Synthetic Sentence Inventory performance; (4) subjects with borderline hearing losses showed greater amounts of dichotic/diotic superiority than those with mild-to-moderate losses. Further research with wearable hearing aids is indicated.

Aged↗
PubMedDate not supplied

Properties of acoustic reflex adaptation.

The dynamic behavior of the acoustic reflex to continuous sinusoidal stimuli was investigated. The major purpose was to determine the temporal characteristics of reflex adaptation as frequency (0.5, 1.0, 2.0, 3.0, 4.0 kHz) and suprathreshold level (6, +12, +18 dB re reflex threshold) were systematically varied. Repeated measurements were made with an impedance bridge on six normal listeners. Both relative and absolute impedance changes were analyzed. The results revealed large intersubject variability. Four general conclusions were reached regarding the effect of stimulus frequency and suprathreshold level on adaptation: 1) as the stimulus frequency increases, the rate of adaptation increases; 2) the adaptation curves appear to form distinct groups, at the low frequencies adaptation rates are significantly slower than those at 2.0 kHz and above; 3) the onset of adaptation occurs at an earlier time for the higher frequencies; and 4) the rate of adaptation was found to be independent of suprathreshold level. The changes in adaptation with frequency of the stimulus may be expressed by an equation involving inter-related time constants for the growth and adaptation portions of the reflex curve in accordance with a descriptive model suggested by Tietze.

Acoustic Stimulation↗
PubMedDate not supplied

Effects of stem design and pre-cooling prostheses on the heat generated by bone cement in an in vitro model.

The necrotizing effects of the heat, particularly at more than 50 degrees C, produced by the exothermic polymerization process associated with the acrylic implant cement polymethylmethacrylate (PMMA) are well documented. The temperature changes that occur are dependent on the thickness of the PMMA. The current study investigates the hypothesis that the heat produced by the bone cement may be reduced by the choice of stem design and by pre-cooling the hip prosthesis. The thermal alterations at the bone-cement interface were measured in an in vitro model. The results indicated that a temperature decrease of approximately 7 degrees C could be achieved by pre-cooling the prosthesis, and by changing the shape of the prosthesis stem from flat and wide to round.

Bone Cements↗
PubMedDate not supplied

Design and implementation of a biomedical image database (BDIM).

We developed a biomedical image database (BDIM) which proposes a standardized representation of value arrays such as images and curves, and of their associated parameters, independently of their acquisition mode to make their transmission and processing easier. It includes three kinds of interactions, oriented to the users. The network concept was kept as a constraint to incorporate the BDIM in a distributed structure and we maintained compatibility with the ACR/NEMA communication protocol. The management of arrays and their associated parameters includes two distinct bases of objects, linked together via a gateway. The first one manages arrays according to their storage mode: long term storage on optionally on-line mass storage devices, and, for consultations, partial copies of long term stored arrays on hard disk. The second one manages the associated parameters and the gateway by means of the relational DBMS ORACLE. Parameters are grouped into relations. Some of them are in agreement with groups defined by the ACR/NEMA. The other relations describe objects resulting from processed initial objects. These new objects are not described by the ACR/NEMA but they can be inserted as shadow groups of ACR/NEMA description. The relations describing the storage and their pathname constitute the gateway. ORACLE distributed tools and the two-level storage technique will allow the integration of the BDIM into a distributed structure, Queries and array (alone or in sequences) retrieval module has access to the relations via a level in which a dictionary managed by ORACLE is included. This dictionary translates ACR/NEMA objects into objects that can be handled by the DBMS.(ABSTRACT TRUNCATED AT 250 WORDS)

Database Management Systems↗
PubMedDate not supplied

Esophagocoloplasty in the management of postcorrosive strictures of the esophagus.

BACKGROUND/AIMS: Esophageal replacement therapy has developed an increasing role in the management of severe esophageal strictures due to caustic ingestion. The aim of this study is to discuss methods of reconstruction and results of them in corrosive esophagitis at our Institute. METHODOLOGY: Thirty-three patients underwent 34 esophagocoloplasties for benign strictures of the esophagus over a 17-year period. The left colon was used in 8 patients, the right colon in 3 patients, and the right colon with the terminal ileum in 23 patients. RESULTS: Three patients died in the first postoperative month, and there was an overall mortality rate of 9%. The most severe complication was graft necrosis (2 patients). The remainder of the patients survived without any deleterious complications. CONCLUSION: Esophageal replacement therapy using the right colon with the terminal ileum is superior to the modalities in terms of the continuity of peristalsis of the interposed bowel segment with an intact ileocecal valve, which decreases the hazard of regurgitation from the colon. It is also easier to perform an anastomosis between the ileum and the cervical esophagus from the point of view of surgical manipulation.

Adolescent↗