PubMed Health⌕ Search

Biomedical subjects

T Najenson

Publications and source records attributed to T Najenson.

At least 19 recordsLinked to original sources
PubMed1992

Gender differences in platelet count and its association with cigarette smoking in a large cohort in Israel.

Cigarette smoking has an effect on platelet function and aggregation although the sensitivity of platelet count in reflecting this phenomenon is not known. The association of platelet count with smoking habits was examined in a cohort of 5017 Israeli industrial workers aged 20-64 years. Males had a significantly lower age-adjusted mean platelet count than females (225,600 vs 247,800/microliters; p less than 0.001). Female smokers had lower platelet counts than non-smokers (231,000 for heavy vs 252,000 for never smokers) with a strong dose-response relationship (p less than 0.0001), whereas among males platelet count was slightly higher in smokers (224,000 for non-smokers vs 227,000 for heavy smokers; p = 0.243). The difference in platelet count between the sexes remained almost identical after controlling for smoking status and hematocrit. In multiple regression analysis, the negative association between smoking and platelet count in women remained highly significant (p less than 0.001) after controlling for ethnic origin, alcohol consumption, body mass, hematocrit, cholesterol and HDL-cholesterol, whereas for males the slight positive association was not significant. The reduced platelet count observed in males compared with females and in female smokers, suggests that platelet count may reflect sex differences in hemostasis and the effects of smoking on the hemostatic system. This may have implications for the mechanisms underlying the pathogenesis of ischemic heart disease and should be explored further.

Adult↗
PubMed1992

Frequency selectivity as a potential measure of noise damage susceptibility.

The notched-noise procedure of Patterson (1974, Journal of the Accoustical Society of America, 55, 802-809; 1976, Journal of the Acoustical Society of America, 59, 640-654) was employed in revealing changes in auditory frequency selectivity (FS) in noise-exposed industrial workers in manufacturing plants in which noise levels in the working environment exceeded 90 dB(A). With 4 kHz as the test frequency, both threshold and FS measures were applied to three groups of non-exposed young adults (total N = 61) for reference values and to workers in three different factories, some ('noise-exposed') working in noise levels over 90 dB(A) (total N = 222). In another study involving 185 workers only the FS test was repeated after a work session, and the results are reported on 31 who worked in high noise levels. Pre-work-shift data showed that when thresholds were better than 30-dB HL most FS values were 10 dB or more, while subjects with hearing threshold levels beyond that showed reduced FS. Two post-work-shift studies of 144 ears of the noise-exposed workers showed significant deleterious changes in both thresholds and FS but the relationships were different in the two studies. The findings indicate that the notched-noise test is sensitive to noise-induced auditory damage, even after a single work-shift. Attractive features of the procedure are that it reduces the need for a quiet test environment and that it can be more resistant to testee manipulation or threshold 'learning' effects, often seen in industrial audiometric testing.

Acoustics↗
PubMed1991

Industrial noise exposure and ambulatory blood pressure and heart rate.

Studies on the effects of long-term exposure to industrial noise on resting blood pressure have yielded inconsistent results. Ambulatory blood pressure and heart rate were monitored simultaneously with noise exposure in normotensive male industrial workers in Israel (85 aged 25 to 44 and 77 aged 45 to 65 years). In the younger group, average ambulatory systolic blood pressure was 3.2 mm Hg higher and diastolic blood pressure 2.3 mm Hg higher in subjects exposed to more than 85 dBa (P less than .001), after adjusting for potential confounding variables. In those aged 45 to 65, ambulatory systolic blood pressure was 3.3 mm Hg lower and diastolic blood pressure unchanged in noise-exposed subjects. Ambulatory heart rate was 2.7 and 2.6 beats per minute higher at the higher noise level (P = .002) in the respective age groups. These findings suggest that industrial noise exposure is associated with higher ambulatory blood pressure and heart rates in men under 45 years old, but the effect on blood pressure appears to diminish considerably with age.

Adult↗
PubMed1989

Ergonomic stress levels, personal characteristics, accident occurrence and sickness absence among factory workers.

This study was designed to evaluate the association of a single, integrated measure of simultaneous exposure to a number of adverse work and environmental conditions, termed the Ergonomic Stress Level (E-S-L), on workers' accident and sickness absence rates. The factors determining the E-S-L were body motion and posture, physical effort, active hazards and environmental stressors. E-S-L evaluation was based on 'walk-through' hazard inventories, direct observations, measurements and interviews. Workers were assigned to one of four stress levels ranging from low (A) to high (D). Subjects were 729 males, aged 20-67 years, employed in five factories in Israel. A linear relationship between E-S-L AND accident incidence was found, increasing from the lowest to the highest E-S-L. Moreover, workers more sensitive to environmental stressors, as indicated by their reported subjective annoyance, showed higher accident rates across all the ergonomic stress levels, a tendency which was statistically significant at levels C and D. On the other hand, sickness absence was significantly related to the overall subjective stress experienced, as manifested by reported job dissatisfaction and somatic complaints, and not directly to E-S-L. These findings highlight the role of aggregate work stress, coupled with individual sensitivity to environmental stressors, in increasing the risk of accidents.

Absenteeism↗
PubMed1989

Temporal characteristics of tapping responses in healthy subjects and in patients who sustained cerebrovascular accident.

Tapping responses were recorded in a group of patients who sustained lesions from cerebrovascular accidents and from an age-matched group of healthy subjects. In each experiment the stimuli were an auditory signal, a flash, or a light touch on the arm, delivered either at random intervals or at fixed time intervals of 1, 2, 3, or 4 s. The tapping response was done with each hand separately (first experiment) or with each hand alternately (second experiment). Healthy subjects, 'predicted' the stimuli (response time less than 150 ms), when the 'preferred' fixed time interval was used. One group of patients (n = 3), did not predict the stimuli at the preferred fixed intervals when tapping was done with the hand related to the involved hemisphere. The second group of patients (n = 3) did not predict the stimuli when tapping was done with either hand.

Aged↗
PubMed1988

Late neuropsychologic status after childhood head trauma.

A neurologic and neuropsychologic test battery was administered to a sample of 35 children drawn from all those in a defined geographic area who had been hospitalized for head trauma before age 7 during the years 1970-1976. Examination was performed 3 1/2 to 10 years after injury, at age 6-15. Twelve subjects had been diagnosed at the time of injury as suffering moderate insult and had been referred to the metropolitan neurosurgical center, while twenty-three with only mild injury had been retained for observation in a local pediatric ward. The twelve with more severe insult were significantly inferior to the other subjects on the Block Design and Coding subtests of the revised Wechsler Intelligence Scale for Children. The Koppitz score of the Bender Test, the WISC-R scatter, the Benton Visual Retention Test, the GATB Motor Speed Test and the Bourdon-Wiersma Vigilance Test showed less diagnostic power and failed to distinguish between the group with more severe injury and that with less. A detailed and carefully scored neurologic examination also failed to distinguish between the two groups. The findings suggest that relatively common traumatic injury may be associated with detectable late cognitive deficit, and that some WISC-R subtests may be among the best measures for detecting such deficit.

Brain Injuries↗
PubMed1986

Alignment procedure for the optimal fitting of lower limb prostheses.

Systematic methods for optimizing the fitting and alignment of artificial legs were developed in this study. The procedures were based on gait analysis and included the following aspects: stump-prosthesis interface or socket geometry, the selection of components from which the artificial leg was constructed, and dynamic alignment of the prosthesis. The amputee's adaptation to deliberately imposed perturbations in his prosthesis, and the resulting compensatory mechanisms are also discussed.

Amputation, Traumatic↗
PubMed1986

Biomechanical and physiological evaluation of FES-activated paraplegic patients.

Four paraplegic patients with traumatic upper motor neuron lesions at the spinal levels between D5 and D12 were activated by functional electrical stimulation (FES) and evaluated biomechanically and physiologically. After a training program aimed at strengthening the muscles of the lower legs, the patients were able to stand up, maintain the standing position, and walk for short distances while being supported. Biomechanical evaluation included weight bearing on the patients' own legs during standing as measured on a force platform and analysis of the time-distance parameters of the stride during walking as measured on a walkway. Physiological evaluation included heart rate and oxygen consumption at rest, when activated by FES in the sitting position, during standing, and during walking. The results obtained indicate that while significant standing and walking performances are achieved, the corresponding physical effort can reach relatively high levels requiring the support of anaerobic energy sources. The practical implications of these results are discussed.

Adult↗
PubMed1985

A system for evaluating the earning capacity of the disabled.

A comprehensive system for evaluating the earning capacity of disability benefit claimants was developed. It is based on theoretical considerations of the factors constituting the loss of such capacity, and involves assessments made by a multi-disciplinary team (including at least a rehabilitation physician, registered nurse, psychologist and a social worker). Each team member conducts an assessment by means of a questionnaire with a strong emphasis on the claimant's functional capacity. In this study the physician was requested to evaluate the claimant according to a "profile of insufficiencies" in addition to the traditional percentage system which is used to reflect the degree of impairment. The results obtained with the first sample of 50 examinees are reported in this paper. The comprehensiveness of the variables covered by the team are demonstrated. A composite score agreed upon by the team was a better predictor of the final degree of disability (determined by an independent disability commission) than each team member's independent assessment. In addition, the "profile of insufficiencies", representing a functional approach to the medical evaluation, proved to be superior to the percentage system commonly used.

Adult↗
PubMed1985

In vivo biomechanical evaluation of nail-plate fixation of femoral neck fractures of rehabilitated patients.

A major advantage of internal fixation of intertrochanteric fractures is that it can normally be followed by early and fast rehabilitation of the patient, finding expression in weight bearing and locomotion abilities of the patients. Complications which nevertheless occur, are mostly of mechanical origin. The purpose of our study was to evaluate the biomechanical performance of rehabilitated patients treated with four different types of nail-plates. Forty nine patients (12 men and 37 women) with walking ability, and with an average age of 70.5 years, were tested on a 10 m walkway, instrumented for the monitoring of the time distance parameters of the stride. This method of evaluation is especially suitable for pathological gait, free or supported, as it does not impose any constraints on the natural and individual walking trend of the patient. The average time elapsed between the actual fracture and the locomotor test was 764 days, implying that the investigated patients formed a homogeneous, well-rehabilitated group. The main average stride results were as follows: contact time 1.25 sec, double contact time 0.41 sec, stride length 68.2 cm, velocity 51.39 cm/sec and symmetry 0.51. No significant differences were found in these parameters between the subgroups of patients using different nail-plates. These results show that while the biomechanical performance of the patients with their implants was satisfactory (good walking symmetry) this group can be characterized by its smaller stride and slower gait, compared to those of a healthy population of the same age.

Activities of Daily Living↗
PubMed1985

Biomechanical evaluation of an adjustable patellar tendon bearing prosthesis.

The purpose of this study was to determine the relation between geometry of the patellar tendon (PT) insertion in the socket and the dynamic load transmitted through the PT, in a patellar tendon bearing (PTB) prosthesis. The dynamic load was measured by a specially constructed two-component load cell, which was mounted on the experimental prosthesis. Geometry of the PT insertion relative to the socket was altered by adjusting the location of the mounting frame-load cell assembly. Evaluation of performance of the prosthesis in the range of geometries investigated was made objectively by gait analysis of the patients. The latter was performed on a 10 m walkpath, including at halfway two forceplates, from which the foot-ground forces were recorded. Simultaneously, the PT forces on the prosthesis, as sensed by the load cell were monitored. Computer processing of the data included full analysis of the force-trace and the determination of criteria for optimization of the PT insertion. The resulting criteria were those which expressed minimization of abnormalities in the foot-ground forces of each patient, such as vertical and braking forces and their timings. The complete optimization procedure, which was undertaken for two below-knee male amputees, indicated the correct positioning of the PT insertion, actually taken in the final fitting procedure of the socket of the prosthesis.

Adolescent↗
PubMed1985

Prediction of functional outcome in hemiplegic patients.

A follow-up study of 40 hemiplegic patients two years after discharge from hospital was aimed at (a) identifying variables capable of predicting general functional ability in everyday life (work, home, family and social life) and (b) examining the relationship between levels of functioning and subjective evaluation of their rehabilitation state. The results showed that a composite measure of functioning ability was closely related to self-reports of satisfaction in significant areas of life: physical well-being, emotional security, satisfaction of family and social needs and vocational self-actualization. The best objective predictor of overall domestic and outdoor functioning was the primary ADL (eating, dressing, bathing, etc.). Other significant variables were ambulation (walking freely for 300 meters), sustaining mental load and emotional acceptance of disability. Predisposing and concurrent diseases (such as congestive heart failure, diabetes mellitus, hypertension and others) were not found to be of predictive value. The findings thus obtained could provide the physician with a good prognostic tool to evaluate the rehabilitation outcome of hemiplegic patients. They also suggested that intervention aimed at emotional acceptance of disability could facilitate the rehabilitation process.

Activities of Daily Living↗
PubMed1985

The "key-form" system for data collection in disability evaluation.

A new system for comprehensive disability evaluation has been developed in the framework of our Hospital. This system is based on multidisciplinary evaluation during one day of tests and the summarization of the data collected. The process takes place at the Institute for Functional Evaluation, a joint project of the National Insurance Institute and the Loewenstein Hospital in Israel. The process was designed to provide the basis for the determination of the degree of disability according to the requirements of the General Disability Law. In order to carry out the experimental program a computerized system of recording was created. The method of recording is based upon the "Key-form" where the different systems of the body appear one after the other and next to them the term "normal" or "abnormal". In the case of an abnormal mark, the tester goes on to the next stage which involves completion of a detailed form for that system. The forms are coded for the transfer of information to the computer without intermediary stages and this enables processing of a vast amount of data with relative ease. The system enables compilation of individual profiles and statistical tables and analysis. Theoretical and practical applications of the system are discussed on the basis of the pilot study.

Data Collection↗
PubMed1985

Criteria for referral of CVA patients for rehabilitation.

A multi-stage follow-up project is in progress at the Loewenstein Rehabilitation Hospital. In the first stage, a group of 153 patients was examined while in the acute phase of CVA (1 to 5 days from stroke), and again 6 months later, by a physician, a physiotherapist and an occupational therapist. Medical, demographical and functional profiles were determined. The most severe cases were admitted for rehabilitation and those with apparently good functioning ability were discharged to their homes. Six months later, the group referred for rehabilitation remained at a very low functional level (35% of them were still at the rehabilitation hospital); on the other hand, those sent home were lacking in general function (37%), in spite of their good ADL and hand performance. Most strikingly, 72% were not engaged in any meaningful activity. Age proved to be a strongly limiting factor. A more selective criterion for referral is required, while allowing patients with medium-grade cognitive and locomotor disturbances the chance of admission to rehabilitation.

Activities of Daily Living↗
PubMed1985

Divided attention in brain-injured patients.

Clinical observations have shown that brain-injured patients perform poorly in tasks requiring attention. While selective and sustained attention has been extensively investigated, there is little systematic information on how brain-injured patients perform on divided attention tasks requiring simultaneous handling of and responding to two sources of information. This study was designed to analyse the behavior of hospitalized brain-injured patients as compared with matched normal controls in performing a dual task consisting of pursuit motor tracking coupled with delayed digit recall (DDR). Four two-minute trials were given. Time on target (TOT) and number of recall errors were recorded. It was assumed that the brain-injured group would (a) have lower TOT and more recall errors; and (b) show less learning effect. Results confirmed both expectations: (1) for the brain-injured group, TOT was lower and did not improve across trials; moreover, the number of recall errors was higher, increasing across trials; (2) for the control group, the number of recall errors was negligible across trials and TOT improved with time; (3) the normal trade-off between two simultaneous difficult tasks was not observed in the brain-injured group as they failed in both tasks; (4) the number of recall errors of the brain-injured subjects markedly increased towards the end of each trial, suggesting rapidly increasing fatigue. Thus, brain-injured patients appeared limited not only in their attention capacity but also in the variety of strategies they employ in processing information.

Adult↗
PubMed1985

Attention capacity limitation, psychiatric parameters and their impact on work involvement following brain injury.

A follow-up study conducted among brain-injured patients explored the correlation between attention capacity limitation and psychiatric parameters as well as their impact on work involvement, two years after hospitalization. Capacity limitation was identified as difficulties in dual-task performance which requires simultaneous attention and response to two sources of stimulation. Poor performance on one or both tasks included in the dual-task paradigm (pursuit motor tracking task and a verbal task) was correlated with psychiatric parameters of behavior, personality and thought. This also correlated with the inability reported by the patients to concentrate for long periods of time and to the feeling of fatigue after physical and mental effort. In addition, it was found that dual-task performance correlated with work involvement. It was concluded that there is a reciprocal relationship between the variables studied. Attention capacity limitations are manifested in various psychiatric parameters; conversely, some psychiatric parameters affect the performance on the dual-task. This highlights the difficulty such patients have in coping with work demands and their consequent inability to maintain steady employment.

Adult↗
PubMed1985

Auditory perception in patients with CVA without aphasia.

Tests of central auditory function were performed variously on 64 patients with hemiplegia who had suffered a single stroke but with minimal or no aphasia symptoms and with essentially normal hearing. Both right and left hemisphere lesions were represented for comparison of effects on the tests. Reports of central auditory dysfunction generally assume localization in the temporal lobes. Since it was apparent that our tests were revealing positive findings in patients in whom there was no recognized evidence of temporal lobe involvement we deliberately selected for one study 34 patients without clinical signs of such lesions. The tests required selective listening in which patients had to a) perceive and repeat a prime message in the presence of a simultaneously competing meaningful message, either under earphones or in the sound field (loudspeaker), and b) repeat all words in a classic dichotic listening task. The tests reveal different dysfunctions in right vs left hemisphere damage and document that compensatory transfer of function from the usually dominant left side to the fight hemisphere usually occurs only in young children. The dysfunctions appear to be unrelated to temporal lobe lesions.

Adult↗