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Biomedical subjects

J A Gliner

Publications and source records attributed to J A Gliner.

At least 19 recordsLinked to original sources
PubMed1989

Internal and external validity in two studies that compared treatment methods.

Research comparing the effectiveness of two treatments offers both strengths and weaknesses for occupational therapy. Although it is worthwhile to determine which of two treatments works best for a particular problem, methodological problems may arise that preclude a valid conclusion. To draw valid conclusions from research, criteria for internal validity and external validity must be satisfied. The two preceding articles in this issue are examples of studies that used between-groups experimental methodology to compare the effectiveness of two different treatments. This paper evaluates the above-mentioned studies on the basis of principles of internal and external validity. One of these studies (Jongbloed, Stacey, & Brighton, 1989) was truly experimental, whereas the other study (Groves & Rider, 1989) was quasi-experimental. Results from both studies were similar because, in each study, both of the treatment groups improved, but there were no significant differences between treatments. Absence of a true control group in both studies presented limitations on the conclusion that both treatments worked equally well.

Analysis of Variance↗
PubMed1987

Bilateral hand performance with divided attention after a cerebral vascular accident.

A divided attention task was used with 10 left or right cerebral vascular accident (CVA) subjects who had return of functional movement in the affected extremities. The primary task was one subtest of the Jebson Hand Function Test. The secondary task was a foot press to a series of auditory cues. Four measurements were obtained for each subject at intervals of 1 month, 2 months, and 3 months after the stroke. Comparison scores on this procedure were also obtained on 5 normal subjects. The results indicated that dividing attention in the CVA subjects significantly decreased the performance on the primary task. The performance with the affected limb improved over the 3-month time period and reached a level of performance that was not significantly different from that of the unaffected limb for either the undivided or divided attention task. Implications for occupational therapy environments and consideration of attention limitations are discussed.

Aged↗
PubMed1985

Purposeful activity in motor learning theory: an event approach to motor skill acquisition.

This paper presents the event approach to motor skill acquisition as a theoretical treatment of the learning and relearning of motor skills; the emphasis is toward rehabilitation of physical dysfunction. Purposeful activity is viewed as a necessary prerequisite for the formation of coordinative structures, which are the bases for skilled movement. Traditional approaches to motor learning, which focus primarily on the actor, are seen as inadequate to accurately describe motor skill acquisition. The event approach treats the actor and the environment as inseparable in the acquisition of skills. Using this approach, I hope to establish a common ground and collaborative relationships between the disciplines of occupational therapy and motor learning.

Adult↗
PubMed1983

Carbon monoxide exposure and information processing during perceptual-motor performance.

This study examined the influence of exposure to ambient carbon monoxide resulting in final carboxyhemoglobin (COHb) levels of approximately 5.0% on the ability to process information during motor performance. Subjects (n = 16) performed a primary reciprocal tapping task and a secondary digit manipulation task singly and/or concurrently during 2.5 h exposure to room air (0 ppm CO) or 100 ppm CO. Five levels of tapping difficulty and two levels of digit manipulation were employed. Tapping performance was unaffected when COHb levels were as high as 5%. However, at this level of COHb it was noted that CO exposure interacted with task difficulty of both tasks to influence reaction time on the digit manipulation task. It was concluded that motor performance was not influenced by exposure to CO leading to COHb concentrations of 5%. Task difficulty was a significant factor mediating behavioral effects of CO exposure.

Adult↗
PubMed1983

Effect of threshold loads on voluntary control of slow and rapid inspiratory movements.

The purpose of this study was to examine the hypothesis that voluntarily produced inspiratory movements are preplanned. Subjects performed both rapid (0.5 s) and slow (2.0 s) voluntary inspirations to a target volume of 50% of their inspiratory capacity under two conditions: 1) normally unloaded with random loading; and 2) normally loaded with random unloading. The load was a 10 cmH2O threshold load. When the load was unexpectedly applied, the subjects undershot the target volume by 397 ml (fast) and 284 ml (slow). When the load was unexpectedly removed, the subjects overshot the target volume by 303 ml (fast) and 224 ml (slow). The duration of inspiration did not change significantly. These observations are consistent with an "impulse-timing" model of preplanned voluntary movement, which incorporates reflex modification of the movement to compensate for loads which may be added or removed.

Adult↗
PubMed1983

Preexposure to low ozone concentrations does not diminish the pulmonary function response on exposure to higher ozone concentrations.

To determine whether persons repeatedly exposed to low ozone concentrations would demonstrate a diminished responsivity, as a result of adaptation or desensitization, when subsequently exposed to a higher ozone concentration, we performed the following study. Respiratory sensitivity (pulmonary function response) to 2 h of exposure to 0.42 or 0.50 ppm ozone (acute exposure) was determined 3 months before or 6 to 8 wk after the study. Twenty-one subjects (8 men, 13 women) were exposed for 2 h or 5 consecutive days to filtered air, 0.20, 0.20, 0.20, and 0.42 to 0.50 ppm ozone, respectively. There were no significant differences between the responses of men and women to ozone. Subjects were divided into a sensitive group (greater than 20% drop in FEV1) and a nonsensitive group (less than 10% drop in FEV1) on the basis of their responses to the acute exposure. Neither the overall group nor the nonsensitive group showed a significant response to 0.20 ppm. Sensitive subjects (n = 9) showed small but significant decreases in FEV1 on exposure to 0.20 ppm. The predominant finding was that the 3 days of preexposure to 0.20 ppm ozone had no effect on the response to 0.42 or 0.50 ppm ozone on the fourth day (when compared with the previous acute exposure to 0.42 or 0.50 ppm). We conclude that subjects repeatedly (3 times) exposed to a low (0.20 ppm) concentration of ozone do not demonstrate a pulmonary function adaptation or desensitization on a subsequent exposure to a higher (0.42 or 0.50 ppm) ozone concentration.

Adaptation, Physiological↗
PubMed1983

Carbon monoxide and human performance in a single and dual task methodology.

Does carbon monoxide (CO) exposure limit man's ability to time share two concurrent tasks? In our study 15 subjects underwent two different 2.5-h exposures to either filtered air or to 100 ppm CO. They performed two tasks singly and in combination. The central task was a compensatory tracking task with three levels of difficulty, whereas the peripheral task was a signal detection task with three probabilities of signal occurrence. When HbCO levels reached 5% (during the last half hour of the exposure) performance on the peripheral signal detection task was altered. This was demonstrated by a 6% decline in signals detected correctly (p less than 0.05). This decline in signals detected was found when the signal detection task was performed alone. These results suggested that exposure to CO decreased arousal and interacted with fatigue to produce decreases in performance.

Adult↗
PubMed1982

Wandering atrial pacemaker associated with repetitive respiratory strain.

Electrocardiographic responses of body-builders and control subjects obtained during the performance of static and dynamic Valsalva maneuvers were studied to determine the causative stimulus for wandering pacemaker activity. The incidence of shifting or wandering pacemaker was nearly double in body-builders, suggesting that this is an occupational or activity-related arrhythmia. The causative mechanism is briefly discussed.

Arrhythmias, Cardiac↗
PubMed1981

Adaptation to ozone: duration of effect.

Repeated ozone exposure induces an adaptative response whereby subsequent ozone exposure induces little or no pulmonary function change. The time course of the adaptation and the persistence of this adaptation was determined in 24 subjects. Subjects were studied for 125 min while they exercised intermittently. They were exposed to filtered air for 1 day and then in the next week for 5 consecutive days to 0.5 ppm ozone. After the fifth day, subjects were randomly assigned to return for one more ozone exposure at 1, 2, or 3 wk. The greatest decrement in FEV1 occurred on the second day of exposure. The number of consecutive ozone exposures required to produce adaptation varied from 2 to 5 days. Persistence of adaptation in ozone-sensitive subjects (initial decrease in FEV1 greater than 10%) showed marked individual variability, but the duration of adaptation was shortest for the more sensitive subjects. Adaptation, on the average, lasted for less than 2 wk, being as short as 7 days and as long as 20 days. We concluded that more sensitive subjects required more daily sequential exposures in order to adapt.

Adaptation, Physiological↗
PubMed1980

Psychomotor performance during ozone exposure: spectral and discriminant function analysis of EEG.

Two experiments were conducted to evaluate the effects of ozone on the electroencephalogram during psychomotor performance. The first experiment consisted of a 2-h visual sustained attention task in room air and 0.75 parts per million (ppm) ozone. The second experiment was a divided attention study which combined a visual choice reaction time situation with an auditory sustained attention task. Ozone levels in this experiment were 0.0 ppm, 0.3 ppm, and 0.75 ppm. Spectral and discriminant function analyses were performed on the EEG collected during these studies. Attempts were made to categorize the EEG between different ozone levels, at rest, during each task performance, and between task and no-task performance within each ambient air condition. Discriminations between conditions for individuals were quite good, but discriminations for the combined subjects were disappointing with the exception of those between task and no-task conditions, which were moderately good.

Adult↗