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Biomedical subjects

J Montplaisir

Publications and source records attributed to J Montplaisir.

At least 73 records · Page 4Linked to original sources
PubMed1996

Comparisons between SPECT and quantitative EEG measures of cortical impairment in mild to moderate Alzheimer's disease.

This study aimed at examining correlations between quantitative REM sleep EEG, regional cerebral blood flow measured by single photon emission computerized tomography (SPECT) and global cognitive functioning in nine patients with mild to moderate Alzheimer's disease. REM sleep EEG was not correlated with SPECT measures in any of the 6 regions studied. However, degrees of interhemispheric asymmetry calculated by both measures were concordant for the parieto-occipital region. Mini-mental state score correlated with REM sleep EEG slowing for left frontal, left and right parieto-occipital and left temporal regions but was not correlated with SPECT measures for any of the six regions. These results suggest that quantitative REM sleep EEG would be more useful than SPECT for evaluating cerebral dysfunctions in mild to moderate Alzheimer's disease.

Aged↗
PubMed1996

Is interhemispheric connectivity reduced after callosotomy? A critique.

A recent case report of interhemispheric correlational measures in a callosotomized patient by Corsi-Cabrera, Trías, Guevara, Haro, and Hernández in 1995 provided evidence taken by the authors of the study to suggest that the corpus callosum may not be crucial to interhemispheric coupling. This conclusion was proposed even though (1) presurgical correlation measures necessary for evaluating coherence changes produced by surgery were not available for this subject and (2) previous studies presenting evidence inconsistent with their conclusions were not discussed. In view of these two shortcomings, the authors' conclusion concerning callosal function may be premature.

Brain Mapping↗
PubMed1995

A 20-h recovery sleep after prolonged sleep restriction: some effects of competing in a world record-setting cinemarathon.

The recovery sleep of a 21-year-old normal woman was assessed after she had endured 11(1/2) days of sleep restriction in a world record-setting film-viewing marathon. An exceptional sleep debt was observed as indicated by an instanteous sleep onset, a high sleep efficiency, and a total sleep duration of over 20 hours. Other striking features of this recovery sleep were very short latencies to stages 3 and 4 sleep, return of Stage 4 sleep after 14.5 h, REM and SWS sleep rebound, and a linear increase in REM sleep efficiency across 14 consecutive REM-NREM episodes. Seven of nine home dreams reported after this recording contained competition themes, but none relating to the marathon films. Comparisons of the present results with those from subjects in previous record-setting events suggest possible explanations for the extremely long recovery sleep. Results also suggest that analyses of multiple consecutive sleep cycles may provide novel ways of assessing hypotheses about regulation of the REM-NREM cycle.

Journal Article↗
PubMed1994

Significance probability mapping: the final touch in t-statistic mapping.

Significance Probability Mapping (SPM), based on Student's t-statistic, is widely used for comparing mean brain topography maps of two groups. The map resulting from this process represents the distribution of t-values over the entire scalp. However, t-values by themselves cannot reveal whether or not group differences are significant. Significance levels associated with a few t-values are therefore commonly indicated on map legends to give the reader an idea of the significance levels of t-values. Nevertheless, a precise significance level topography cannot be achieved with these few significance values. We introduce a new kind of map which directly displays significance level topography in order to relieve the reader from converting multiple t-values to their corresponding significance probabilities, and to obtain a good quantification and a better localization of regions with significant differences between groups. As an illustration of this type of map, we present a comparison of EEG activity in Alzheimer's patients and age-matched control subjects for both wakefulness and REM sleep.

Aged↗
PubMed1994

[The restless leg syndrome: a condition associated with periodic or aperiodic slowing of the EEG].

There are several new developments with regard to semiology, diagnosis, physiopathology and the treatment of restless leg syndrome (RLS). We present here the hypothesis that motor manifestations of the RLS are synchronous to slowing of the cortical activity as measured by the spectral analysis of the EEG. When the subject is resting in bed with his leg outstretched, slowing of the EEG is observed, which could be periodic at the frequency of approximately 1 every 20 seconds or sustained. Leg movements can be periodic at the frequency of approximately 1 every 20 seconds or sustained. Leg movements can be periodic or aperiodic accordingly. On the contrary, periodic leg movements in sleep (PLMS) occur in close temporal relationship with periodic arousal. These results raised the hypothesis that leg movements (RLS and PLMS) may appear at a critical level of cortical activation. This level is reached during sleepiness in the awake subject or during periodic micro-arousal when the subject is asleep. Other results suggest that these periodic changes in the level of cortical activation may also modulate other abnormal motor behavior in sleep such as rhythmic masticatory muscles activity as seen in sleep bruxism. The same mechanism may also be involved in setting the duration of apneic episodes during slow-wave sleep.

Electroencephalography↗
PubMed1994

[Movement disorders during sleep: attempt at classification].

We suggest a classification for abnormal motor behavior during sleep based upon clinical and research studies. Abnormal motor behaviors are classified into four types: aperiodic myoclonic contractions, periodic and stereotype movements, complex and disorganized motor behaviors, complex and organized motor behaviors. Examples for each type are given to support the classification.

Diagnosis, Differential↗
PubMed1994

Modafinil: a double-blind multicentric study.

Modafinil is a central putative alpha-1 postsynaptic agonist with vigilance-promoting properties. Fifty narcoleptics (33 male and 17 female) participated in a multicentric study aimed at assessing the effects of the compound on night sleep, feeling on awakening, excessive daytime sleepiness and cataplexy. Modafinil was administered in a double-blind cross-over design at a daily dosage of 300 mg versus placebo. The duration of the study was 12 weeks, including a 2-week "run in" period with placebo, a first 4-week treatment period with either modafinil or placebo, a 2-week wash-out period with placebo and a second 4-week treatment period with either placebo or modafinil. Daily evaluation was based on a sleep log, visual analog scales, a sleep questionnaire and a clinical global index. Sleep laboratory evaluation took place on nights 1, 28, 42 and 70. It included 1 night of polysomnography preceded by a questionnaire on therapeutic and side effects, and a maintenance of wakefulness test (MWT). Sleep logs did not show any modification of night sleep, but a reduction of daytime sleepiness and sleep. Feeling on awakening was not modified. An overall benefit was noted by physicians as well as by patients. MWT disclosed a positive effect of modafinil on excessive daytime sleepiness. Cataplexy was not modified.

Adult↗
PubMed1993

Persistent neuropsychological deficits and vigilance impairment in sleep apnea syndrome after treatment with continuous positive airways pressure (CPAP).

The obstructive sleep apnea syndrome is characterized by nocturnal sleep disturbance, excessive daytime sleepiness and neuropsychological deficits in the areas of memory, attention, and executive tasks. In the present study, these clinical manifestations were assessed in apneic patients before and 6 months after treatment with nasally applied continuous positive airway pressure (CPAP). CPAP treatment was found to restore normal respiration during sleep and to normalize sleep organization. Daytime vigilance greatly improved with treatment but some degree of somnolence as compared to normal controls persisted. Similarly, most neuropsychological deficits normalized with treatment. The exception was for planning abilities and manual dexterity, two neuropsychological deficits that have been found to be highly correlated with the severity of nocturnal hypoxemia. These results raise the possibility that anoxic brain damage is a pathogenic factor in severe obstructive sleep apnea syndrome.

Adult↗
PubMed1993

Effects of modafinil on symptomatology of human narcolepsy.

We studied the effects of modafinil, a putative central alpha-1 agonist, on the excessive daytime sleepiness (EDS) of 10 narcoleptic patients while using a double-blind design and objective measurements of vigilance. There were two treatment periods, in which either modafinil or placebo was used; each lasted four weeks and was preceded by a 2-week "run-in" period and separated by a 2-week "wash-out" period. The effects of treatment on EDS were evaluated by daily home questionnaires and a psychomotor performance test, the Four Choice Reaction Time Test (FCRTT). Modafinil reduced the daily number of sleep attacks significantly, and markedly improved performances during the FCRTT. Results of this study suggest that modafinil is effective in treating EDS in narcolepsy, and that noradrenergic mechanisms could be involved in the physiopathology of EDS in that disorder.

Adult↗
PubMed1993

Effects of bromocriptine in human narcolepsy.

Bromocriptine, a preferential D2 receptor agonist, was administered to six human narcoleptic patients during a double-blind, cross-over study. Laboratory sessions consisted of two all-night polysomnographic recordings and three daytime tests of vigilance: the Analogue Vigilance Scale (AVS), the Maintenance of Wakefulness Test (MWT), and the Four-Choice Reaction Time Test (FCRTT). No change in nocturnal sleep organization, daytime somnolence, or psychomotor performance was observed during bromocriptine administration. Periodic limb movements in sleep (PLMS) were significantly reduced during bromocriptine condition. These results suggest that D2 receptors are unlikely to play a major role in the physiopathology of human narcolepsy, and support the hypothesis that dopaminergic mechanisms are involved in PLMS.

Adult↗
PubMed1993

Dreaming in agenesis of the corpus callosum: laboratory and home assessment of four cases.

Laboratory and home dream recall was studied in four subjects with agenesis of the corpus callosum and in four control subjects who were matched for age, gender, and handedness. In addition, the structural and emotional content of home dreams was compared for these two groups. Results indicate that acallosal subjects recalled fewer dreams in the laboratory than did control subjects, but recalled the same number of dreams at home. They also reported more contentless dreams in both situations. Furthermore, although acallosal subjects used fewer words to describe their dream content in both contexts, the number of content categories they reported differed little from the number reported by control subjects. However, some trends were found for acallosal's home dreams to differ from those of controls, i.e. more dreams with known characters and fewer dreams with unknown characters, animals, and colours. Differences in emotional contents were few; acallosals reported more distress than controls. The shorter length of acallosals' dreams might be explained, in part, by their lower verbal IQs. Other characteristics of dream content (e.g. more distress, fewer dreams with unknown and animal characters) may reflect limited social experiences in this group. However, the greater frequency of contentless dreams and the lower frequency of dreams with colour are trends consistent with the possibility that the corpus callosum may be implicated in processes of dream production and dream recall.

Journal Article↗
PubMed1993

Decreased interhemispheric EEG coherence during sleep in agenesis of the corpus callosum.

Inter- and intrahemispheric EEG coherence was studied in 4 subjects with agenesis of the corpus callosum (ACC) and in 4 matched controls through different states of the sleep/wakefulness cycle. Interhemispheric coherence was calculated between homologous prefrontal, frontal, central, parietal and occipital electrode pairs whereas intrahemispheric coherence was calculated between all adjacent, unihemispheric electrode pairs. EEG samples were recorded from stage 2, stages 3 + 4 and stage REM sleep and the eyes closed waking state. Interhemispheric coherence measures indicated lower values for ACC subjects than for control subjects for most brain regions; the occipital cortex was least affected. These results further validate the interhemispheric coherence function as a measure of activity in the corpus callosum and suggest that occipital measures may index activity localized in the posterior commissure. Intrahemispheric coherence measures indicated very few differences between the two groups, a result consistent with the suggestion that there is no specialized intrahemispheric compensation in ACC.

Adolescent↗
PubMed1993

Effects of bromocriptine on periodic limb movements in human narcolepsy.

We studied the effects of bromocriptine on periodic limb movements in sleep (PLMS) of narcoleptic patients. Bromocriptine significantly reduced the number and index of PLMS without improving the nocturnal sleep disruption in that disorder. These results support the hypothesis that dopaminergic mechanisms are involved in the physiopathology of PLMS, and suggest that PLMS do not play a major role in the nocturnal sleep disruption of narcoleptic patients.

Adult↗
PubMed1992

Spectral analysis of the rapid eye movement sleep electroencephalogram in right and left temporal regions: a biological marker of Alzheimer's disease.

Spectral analysis of electroencephalograms (EEGs) for both wakefulness and rapid eye movement (REM) sleep was performed over the temporal regions in 8 patients with mild to moderate Alzheimer's disease and in 8 age-matched control subjects. EEG slowing in Alzheimer patients was found to be much more prominent during REM sleep than during wakefulness. In addition, asymmetry on the awake EEG of Alzheimer patients was found to be even more prominent than on the REM sleep EEG. When EEG values of the most impaired hemisphere during REM sleep were examined, no overlap was found between the two groups either for the ratio of slow to fast frequencies or for percent power of each of the frequency bands. This was not the case for the awake EEG. These results suggest that diagnostically meaningful cutoff values for discriminating patients with mild to moderate Alzheimer's disease from age-matched control subjects can be derived from the REM sleep EEG of the temporal lobe.

Aged↗
PubMed1992

DQB1-0602 (DQw1) is not present in most nonDR2 Caucasian narcoleptics.

Human narcolepsy is a genetically determined disorder of sleep strongly associated with the human leucocyte antigens (HLA) DR2 and DQw1. In black narcoleptic patients, susceptibility for narcolepsy is more closely related to a specific gene subtype of DQw1, DQB1-0602, than to DR2. About 30% of black narcoleptic patients are nonDR2, but all carry the HLA DQB1-0602 gene. In the present study, we have tested caucasian nonDR2 cataplectic patients (6 sporadic cases and 7 familial cases from 3 multiplex families) for the presence of the HLA DQB1-0602 and DQA1-0102 (DQw1) using a specific polymerase chain reaction (PCR)-oligotyping technique. None of the patients was DQB1-0602 or DQA1-0102 positive, thus proving that, in caucasians, DQB1-0602 and DQA1-0102 (DQw1) are not prerequisites for the diagnosis of narcolepsy. Further studies with more patients are warranted to exclude the possibility that a few caucasian patients carry rare haplotypes with DQB1-0602 independently of DR2.

Amino Acid Sequence↗