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Biomedical subjects

P Hazemann

Publications and source records attributed to P Hazemann.

At least 19 recordsLinked to original sources
PubMed2002

[Recurrent idiopathic stupor in a patient: responsibility of exogenous or endogenous benzodiazepines?].

Recurrent transitory consciousness loss represents a neurological diagnostic difficulty. A 56 year old man was hospitalised for recurrent stupor episodes. Explorations allowed to exclude hepatic, renal or respiratory failures, epilepsy or sleep disorder. During a stuporous state, since the patient was clearly awakened by flumazenil administration, the retained diagnosis was idiopathic recurrent stupor, a rare and not well-known disease. The authors discuss the possible effect of a treatment with zolpidem, though its pharmacokinetic characteristics did not correspond to the patient manifestations, and the possible responsibility of endogenous benzodiazepines in the genesis of this trouble.

Benzodiazepines↗
PubMed1990

Sensory and cognitive event related potentials in workers chronically exposed to solvents.

To obtain objective measures of possible impairment due to organic solvents, auditory, visual and somatosensory evoked potentials and cognitive event related potentials were recorded in a group of 13 workers occupationally exposed to a mixture of various solvents. The patients were compared to healthy subjects and to chronic alcoholics seen during post-alcohol withdrawal. Auditory and visual evoked potentials were almost normal but somatosensory evoked potentials showed a slight decrease of peripheral conduction velocities and an increase of central conduction times more marked in the solvent exposed workers who were also alcoholics. The late "cognitive" components reflecting attention processes (N2 and P3) were normal. Solvent-exposed workers and alcoholics were both characterized by some difficulty in modulating their attentional resources according to task demands, as reflected by a tendency to responses (N1, N2 and P3) of similar amplitudes whether the stimulus was or was not the target. These findings support the presence, in solvent exposed workers, of minor dysfunction of the nervous system at both peripheral and cortical levels potentiated by alcohol as well as of mild cognitive impairments concerning attention processes.

Adult↗
PubMed1988

Effects of lead and mercury intoxications on evoked potentials.

Pattern reversal, brain stem auditory and somatosensory evoked potentials (PREPs, BAEPs, SEPs) have been recorded on 13 patients occupationally exposed to inorganic lead compounds, in 9 patients occupationally or accidentally exposed to inorganic mercury compounds and in 26 chronic alcoholics. The results were compared to those of a normal control group. Peripheral conduction velocities were decreased in lead exposed workers and in alcoholics, but not modified in the mercury exposed patients. In the three exposed groups, an amplitude increase (PREPs and upper limb SEP cortical components), more important in the mercury group and an increase of central conduction time in case of lower limb stimulation, could be interpreted as early signs of nervous cortical impairment.

Adult↗
PubMed1979

Effect of ageing and occupational activity on active wakefulness.

44 people were recorded by a telemetric system during 8 h of daily occupational activity. 24 were factory personnel (12: mean age 37 years, and 12: mean age 53 years) and 20 were univeristy researchers (10: mean age 39 years, and 10: mean age 53 years). Recordings were made concerning EEG, EOG, EMG, and EKG. At 35 years no differences were observed. At 50 years the organization of wakefulness was different for the two occupational activity groups. Although stable for the moment seemed to play a prominent role in the modulation of wakefulness.

Adult↗
PubMed1978

Spontaneous variations in level of arousal among aged individuals. Correlations with functional abilities and mental performances.

The aim of this study was to assess whether spontaneous interindividual variations in arousal level appreciated by telemetric recordings of physiological variables were related to mental performance and functional ability in institutionalized aged subjects. The sample studied was made up of 18 subjects (16 women and 2 men) aged 82-97, living in an old age home in Paris. Telemetric recordings of EEG, EKG, EMG and EOG were obtained over 8-hour periods, during the subjects' normal daily activity schedule. The Stockton Geriatric Rating Scale (SGRS), Benton's Visual Retention Test (VRT) and the Trail Making Test (TMT) were independently used to assess behaviour and mental performance of these aged persons. All correlations between telemetric data and psychological evaluations (the psychometric tests as well as the rating scale) were highly significant, even once the influence of the cultural level was controlled.

Activities of Daily Living↗
PubMed1975

Effects of time and tasks upon auditory and somatosensory evoked potentials in man.

Auditory evoked potentials (AEPs) recorded from the vertex and somatosensory evoked potentials (SEPs) recorded from the somatosensory and motor areas and vertex were examined during visual and auditory discrimination tasks, with and without motor responses, and during motor tasks alone in normal human subjects. These procedures allowed the separation of sensory discrimination from motor activity effects on the evoked potentials. It was observed that EPs were modified systematically by task and by temporal variables, even though vigilance, as evaluated through EEG recording and performance level, was stable throughout the experimental recording session. 1. AEPs were minimally influenced by time, but very sensitive to task. Inversely, the SEP amplitude decreased considerably with time and less with task. There was evidence of time/task interaction. 2. The magnitude of SEP attenuation in time was reduced by intervening rest periods. 3. The sensory modality in which the discrimination task was performed did not influence the effect on EPs. A discrimination task involving a motor response reduced EPs more than a pure discrimination or a pure motor task. The task effect seems to involve a general, mechanism (load imposed upon the subject) not dependent on the particular sensory channel used to deliver task-relevant information.

Auditory Cortex↗
PubMed1975

Effect of voluntary self-paced movements upon auditory and somatosensory evoked potentials in man.

The effect of voluntary self-paced movements upon auditory (AEPs) and somatosensory (SEPs) evoked potentials has been investigated according to the temporal relationship between movement and delivery of test stimuli. EPs were recorded in 7 subjects and averaged in 10 successive epochs extending from 880 msec before to 2500 msec after movement. AEPs were attenuated in all epochs. The decrease was greatest in the 220 msec epoch just following movement and involved components N85 and P170. SEPs were attenuated similarly to AEPs when movements were performed by the hand contralateral to somatosensory stimulation. Of the 5 SEP components, only P40 failed to reflect the attenuation, while P95 showed the greatest amplitude decrease. When stimulation was ipsilateral, SEP amplitude was attenuated only when close to the movement. N65 and P95 decreased while N130 increased. In all subjects the results were consistent for treatments of AEP and SEP (with contralateral movements), whereas large inter-individual differences were observed for the SEP with ipsilateral movements.

Auditory Cortex↗