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Biomedical subjects

J J Askenasy

Publications and source records attributed to J J Askenasy.

At least 19 recordsLinked to original sources
PubMed1996

Inhibition of muscle sympathetic nerve activity during yawning.

Yawning is a complex event that depends largely on the autonomic nervous system. Microneurographic techniques were used to study the mechanism involved in yawning. A series of spontaneous yawns displayed by a healthy 39-year-old male offered us the opportunity to study the muscle sympathetic nerve activity (MSNA) during this phenomenon. It was found that 2 s of yawning inhibited the MSNA recorded at the right peroneal nerve in the lateral knee area, while 3 s of slow expiration succeeding a yawn provoked an MSNA discharge. Blood pressure decreased with each slow expiration by 5-6 mmHg, and increased again with the renewed MSNA discharge. We conclude that yawning is associated with a sympathetic suppression that favours a parasympathetic dominance, as indicated by the MSNA and the decrease in blood pressure. The slow expiration following a yawn is associated with a sympathetic activation marked by an MSNA discharge and an increase in blood pressure.

Adult↗
PubMed1996

The impact of missile warfare on self-reported sleep quality. Part 1.

During the 1991 Gulf War, we investigated the effect of missile attacks through two telephone surveys of a large sample of an urban population that evaluated self-reported sleep quality, stress, fear, depressed mood, fatigue and power of concentration. We surveyed 1,045 people during the Gulf War itself, and we interviewed them again (excluding the chronic insomniacs) 30 days after the war. During the war, 51% of the subjects claimed to be suffering from disturbed sleep. Whereas 13% of the survey population had been chronic insomniacs before the war, 38% developed insomnia during the war. The war provoked reported stress (67.5% of subjects), depressed mood (50.9%), difficulties in concentration (39.7%) and increased fatigue (25%). Four weeks after it ended, 19% of the previously normal subjects were still suffering from insomnia; 5% of the cases of insomnia were developed postbellum. Stress, depressed mood and impaired concentration were found to correlate significantly with subjectively evaluated insomnia. We concluded that modern missile warfare may induce long-lasting insomnia in one-third of the population under threat. A small percentage may develop insomnia postbellum. The risk of developing long-lasting insomnia is higher in those who reported experiencing prolonged stress and depressed moods.

Combat Disorders↗
PubMed1995

Does a subtropical climate imply a seasonal rhythm in REM sleep?

The present study was performed on 615 male subjects referred to the Sleep Medicine Center at Tel Hashomer, Israel, and polysomnographically recorded for a single night between January 1, 1990 and December 31, 1993. The study suggests the existence of a circannual rhythm of rapid eye movement (REM) sleep time with an acrophase during December-January and a nadir during July-September (single cosinor analysis: mesor = 49.7 +/- 0.9, amplitude = 5.9 +/- 1.2, p < 0.001). Both REM sleep time and REM sleep percentage were higher and REM sleep latency shorter during winter and spring than during summer and fall. No dependence of the seasonal REM sleep time rhythm upon age, apnea-hypopnea index or diagnosis type was detected. These data support, for a subtropical climate, results previously obtained in a temperate climate. It is possible that external temperature may be the principal factor influencing the phenomenon.

Adolescent↗
PubMed1994

Dependence on REM sleep of overnight improvement of a perceptual skill.

Several paradigms of perceptual learning suggest that practice can trigger long-term, experience-dependent changes in the adult visual system of humans. As shown here, performance of a basic visual discrimination task improved after a normal night's sleep. Selective disruption of rapid eye movement (REM) sleep resulted in no performance gain during a comparable sleep interval, although non-REM slow-wave sleep disruption did not affect improvement. On the other hand, deprivation of REM sleep had no detrimental effects on the performance of a similar, but previously learned, task. These results indicate that a process of human memory consolidation, active during sleep, is strongly dependent on REM sleep.

Adolescent↗
PubMed1993

Sleep in Parkinson's disease.

Two major sources of dissatisfaction with the quality of life among Parkinsonian patients are the "locomotor disability" and the "nature of their sleep". The main focus of research was directed towards the locomotor disability, but in the last two decades some progress has been made towards the understanding of sleep in PD patients. Sleep in Parkinson's disease is light and fragmented due to an increased skeletal muscle activity, disturbed breathing, impaired biological rhythm and REM-nonREM variations of the dopaminergic receptor sensitivity.

Antiparkinson Agents↗
PubMed1992

About the mechanism of hiccup.

Every new empiric observation made over two millenia fueled the dispute as to whether hiccup (Hc) is a digestive or a respiratory reflex. A review of the literature, focusing attention on the probable mechanism of Hc, shows Hc as a neurogenic dysfunction of the 'valve function' between the inspiratory complex and the glottis closure complex.

Glottis↗
PubMed1990

Different laws govern motor activity in sleep than in wakefulness.

A wide range of elementary and complex motor activities are known to occur during sleep, but very little is known about the basic physiologic condition of the skeletal muscle during sleep. The present study provides evidence that a minute electric random activity constitutes the basic physiologic condition of the skeletal muscles during sleep. During the NonREM stages of each sleep cycle a regression of the continuous random minute activity occurs, followed by a sudden increase of the isolated motor unit action potentials during REM sleep. Particular structural features of the anterior tibial (AT) muscle make it the most active skeletal muscle during sleep. During wakefulness, at rest, the random muscle activity disappears.

Adult↗
PubMed1990

Juvenile Parkinson's disease and its response to L-dopa therapy.

Four youngsters, between the ages of 13-27 years, presented dystonic foot. Two to three years following the appearance of the dystonic foot, cogwheel rigidity and tremor appeared on the dystonic foot side. Treatment with low doses of levodopa/carbidopa consistently reversed the symptoms. "On-off" phenomena appeared in the first years of treatment and persisted for the entire period of 5 to 15 years of illness. No parkinsonian signs were present when the dystonic foot appeared. Based on our observations and on a review of the literature, we conclude that responsiveness to low doses of L-dopa is the major marker of juvenile Parkinson's disease.

Adolescent↗
PubMed1989

Is yawning an arousal defense reflex?

Despite the fact that yawning is a reality of everyday life, its study is not included in the curriculum of medical schools, and most medical textbooks barely mention its existence. Two factors may help to explain this puzzling situation: (a) yawning's borderline position between psychology and neurology, and (b) researchers' lack of understanding as to why people yawn. After review of the literature and personal observation, it is concluded that yawning is a complex arousal defense reflex located in the reticular brainstem with a peripheral and central arche, whose aim is to reverse brain hypoxia. Yawning occurs with loss of interest (boredom) and may or may not be associated with fatigue. By reversing drowsiness, yawning avoids a decreased concentration capacity resulting from borderline hypoxia. It is hoped that this article will stimulate further research on the phenomenon.

Arousal↗
PubMed1989

Association of intracerebral bone fragments and epilepsy in missile head injuries.

Twenty young adults sustained missile injuries in the Lebanese war. They underwent repeated clinical electroencephalographical (EEG), computerised tomography scanning (CT-scan) and polysomnographic (PSG) examinations during a 6-year period. All the patients were young adult males with an average age of 23, previously healthy according to their army profiles. Three of 20 developed between 3 to 14 months following injury generalised tonic-clonic convulsions. The unique common epileptogenic feature characterising the 3 epileptics was the presence of bone fragments in lacerated brain tissue. The possible causal relationship between the presence of the bone fragments and epileptogenesis is discussed.

Adult↗
PubMed1989

Sleep tonus inversion: a feature of juvenile dystonic parkinsonism.

Polysomnographic monitoring of a 16-year-old girl suffering from dopa-responsive dystonic parkinsonism showed a change in the distribution of muscle activity in thigh muscles during different stages of sleep. The hamstring muscles were hypertonic at sleep onset compared with the vastus lateralis of the quadriceps muscles. At the third sleep cycle of each of the 2 nights, the time at which sleep benefit becomes clinically evident, the hypertonia in the hamstring muscles was reversed and the vastus lateralis became more hypertonic. It is suggested that the muscle tonus inversion marks the moment at which the sleep process alleviates the dystonic parkinsonian state manifested at wakefulness as a circardian fluctuation. According to our data, the flexor-extensor tonus inversion during sleep was not yet described in the literature, and may be an associated feature of dopa-responsive dystonic parkinsonism.

Adolescent↗