PubMed Health⌕ Search

Biomedical subjects

Bernard Bioulac

Publications and source records attributed to Bernard Bioulac.

At least 19 recordsLinked to original sources
PubMed2006

Insomniac complaints interfere with quality of life but not with absenteeism: respective role of depressive and organic comorbidity.

BACKGROUND AND PURPOSE: Insomnia is common and associated with poor health status and quality of life. We designed a study to evaluate the impact of insomniac complaints with and without comorbidity on health status and absenteeism. PATIENTS AND METHODS: This is a cross-sectional study performed within a 1-year follow up study on a prospective cohort of French employees. Insomniac subjects (n=986) were compared to control subjects (n=584). Insomniacs suffering from self-reported depressive feelings and behavioral and organic sleep complaints were excluded. RESULTS: Subjects with insomniac complaints (whether with mood or behavioral and organic sleep complaints or not) reported poorer quality of life and had a higher absenteeism rate than controls (9.6+/-31 versus 5.8+/-19 days, P<0.01). A logistic regression model adjusting for depressive and behavioral and organic sleep complaints showed that insomniac complaints were no longer predictive of absenteeism. CONCLUSIONS: Insomniac complaints are strongly associated with deterioration in quality of life but not necessarily with higher absenteeism.

Absenteeism↗
PubMed2006

The effects of coffee and napping on nighttime highway driving: a randomized trial.

BACKGROUND: Sleep-related accidents often involve healthy young persons who are driving at night. Coffee and napping restore alertness, but no study has compared their effects on real nighttime driving performances. OBJECTIVE: To test the effects of 125 mL of coffee (half a cup) containing 200 mg of caffeine, placebo (decaffeinated coffee containing 15 mg of caffeine), or a 30-minute nap (at 1:00 a.m.) in a car on nighttime driving performance. DESIGN: Double-blind, randomized, crossover study. SETTING: Sleep laboratory and open highway. PARTICIPANTS: 12 young men (mean age, 21.3 years [SD, 1.8]). MEASUREMENTS: Self-rated fatigue and sleepiness, inappropriate line crossings from video recordings during highway driving, and polysomnographic recordings during the nap and subsequent sleep. INTERVENTION: Participants drove 200 km (125 miles) between 6:00 p.m. and 7:30 p.m. (daytime reference condition) or between 2:00 a.m. and 3:30 a.m. (coffee, decaffeinated coffee, or nap condition). After intervention, participants returned to the laboratory to sleep. RESULTS: Nighttime driving performance was similar to daytime performance (0 to 1 line crossing) for 75% of participants after coffee (0 or 1 line crossing), for 66% after the nap (P = 0.66 vs. coffee), and for only 13% after placebo (P = 0.041 vs. nap; P = 0.014 vs. coffee). The incidence rate ratios for having a line crossing after placebo were 3.7 (95% CI, 1.2 to 11.0; P = 0.001) compared with coffee and 2.9 (CI, 1.7 to 5.1; P = 0.021) compared with nap. A statistically significant interindividual variability was observed in response to sleep deprivation and countermeasures. Sleep latencies and efficiency during sleep after nighttime driving were similar in the 3 conditions. LIMITATIONS: Only 1 dose of coffee and 1 nap duration were tested. Effects may differ in other patient or age groups. CONCLUSIONS: Drinking coffee or napping at night statistically significantly reduces driving impairment without altering subsequent sleep.

Adult↗
PubMed2006

Increased slow oscillatory activity in substantia nigra pars reticulata triggers abnormal involuntary movements in the 6-OHDA-lesioned rat in the presence of excessive extracellular striatal dopamine.

Since electrophysiological correlates of L-dopa-induced dyskinesia (LID) are almost unknown, changes of striatal dopamine (DA) transmission and electrophysiological activity of the substantia nigra pars reticulata (SNr) were recorded before and after acute L-dopa administration in sham-operated and 6-hydroxydopamine (6-OHDA)-lesioned rats that were previously treated with vehicle or L-dopa for 10 days. Abnormal involuntary movements occurred only in the L-dopa-primed 6-OHDA-lesioned rats that showed after acute l-dopa administration a decrease in firing rate, the highest local field potential power in the theta/alpha band, a consequent oscillatory activity in the same frequency band at the single neuron level and an excessive increase in striatal DA release associated with the lowest level of DA metabolism. These results suggest that increased synchronised afferent activity may drive SNr oscillations in the same frequency band and is associated with abnormal involuntary movements, further suggesting the potential use of desynchronising drugs for managing LID in Parkinson's disease.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2006

Nocturnal sustained attention during sleep deprivation can be predicted by specific periods of subjective daytime alertness in normal young humans.

In our 24-h society, nocturnal sleep-related accidents are common. Because all individuals are not equal in their responses to sleep loss, it is very important to identify predictors of vulnerability to sleep deprivation in normal subjects. We investigated the performance of a cognitive test of sustained attention, electroencephalogram theta/alpha power, subjective sleepiness, and two circadian markers (core temperature and melatonin) in 18 healthy men (nine morning types and nine evening types, 21.4 +/- 1.9 years) during a 36-h sleep deprivation in a constant routine protocol. Sleep need (self-reported) and baseline sleep structure were also investigated. Nighttime performance impairment was defined as the difference between the mean nocturnal number of lapses (00:00-07:30 [corrected] hours) and the mean diurnal number of lapses (07:30-20:30 hours) expressed as a percentage. Feeling fully alert in the morning just after awakening and/or sleepy in early afternoon were the only two factors (Multiple R > 0.80, > 60% of explained variance) which better predicted the decrease in performances of nocturnal operational tasks requiring sustained attention.

Adult↗
PubMed2006

Temporal and spatial alterations in GPi neuronal encoding might contribute to slow down movement in Parkinsonian monkeys.

Although widely investigated, the exact relationship between changes in basal ganglia neuronal activity and parkinsonian symptoms has not yet been deciphered. It has been proposed that bradykinesia (motor slowness) is related either to a modification of the activity of the globus pallidus internalis (GPi), the main output structure, or to a loss of spatial selectivity of the extrapyramidal motor system. Here we investigate the relationship between movement initiation and GPi activity in parkinsonian non-human primates. We compare neuronal encoding of movement in the normal and pathological conditions. After dopamine depletion, we observe an increased number of neurons responding to movement, with a less specific somato-sensory receptive field and a disruption of the selection mechanism. Moreover, the temporal order of the response of GPi neurons in parkinsonian animals is reversed. Indeed, whereas muscle activity and movement are delayed in parkinsonian animals, GPi neuronal responses to movement occur earlier and are prolonged, compared with normal conditions. Parkinsonian bradykinesia could thus result from an impairment of both temporal and spatial specificity of the GPi response to movement.

Action Potentials↗
PubMed2005

Effects of sleep deprivation on Color-Word, Emotional, and Specific Stroop interference and on self-reported anxiety.

The aim of this study was principally to assess the impact of sleep deprivation on interference performance in short Stroop tasks (Color-Word, Emotional, and Specific) and on subjective anxiety. Subjective sleepiness and performance on a psychomotor sustained attention task were also investigated to validate our protocol of sleep deprivation. Twelve healthy young subjects were tested at four-hourly intervals through a 36-h period of wakefulness under a constant routine protocol. Analyses of variance for repeated measurements revealed that self-assessment of sleepiness on a visual analogue scale as well as mean reaction time performance on the sustained attention task, both for the first minute and for 10 min of testing, were worsened by sleep deprivation. Analyses revealed an increase in self-reported anxiety scores on the STAI questionnaire but did not reveal any significant effect after sleep deprivation either on indexes of interference or on accuracy in Stroop tasks. However, analyses showed sensitivity to circadian effect on verbal reaction times in the threat-related (Emotional) and sleep-related (Specific) Stroop tasks. We concluded that 36 h of prolonged wakefulness affect self-reported anxiety and Emotional Stroop task resulting in a cognitive slowing. Moreover, total sleep deprivation does not affect interference control in any of the three short Stroop tasks.

Adolescent↗
PubMed2005

Impact of high-frequency stimulation parameters on the pattern of discharge of subthalamic neurons.

In clinical conditions, high-frequency stimulation (HFS) of subthalamic (STN) neurons in Parkinson's disease is empirically applied at > or =100 Hz (130-185 Hz), with pulses of short duration (60-100 micros) and 1- to 3-mA amplitude. Other parameter values produce no effect or aggravate the symptoms. To gain a better understanding of the mechanisms that underlie the therapeutic action of HFS, we have compared the effects of different combinations of parameter values delivered by clinical stimulators on the activity of STN neurons recorded in whole cell patch-clamp configuration in slices. We showed that none of tested combinations of parameters silenced the neurons. Non-therapeutic combinations i.e., low-frequency pulses (10-50 Hz), even at large amplitude or width, further excited the STN neurons with respect to their spontaneous activity. In contrast, combinations in the therapeutic range (80-185 Hz, 90-200 micros, 500-800 microA) replaced the preexisting activity by spikes, time-locked to the stimuli and thus presenting a striking regularity. When increasing pulse width or amplitude in this high-frequency range, the dual effect was still present but the activity generated became more irregular. We propose that during HFS at clinically relevant parameters, STN neurons behave as stable oscillators entirely driven by the stimulation, giving an average stable STN output that overrides spontaneous activity and introduces high-frequency regular spiking in the basal ganglia network.

Action Potentials↗
PubMed2005

Subthalamic high frequency stimulation resets subthalamic firing and reduces abnormal oscillations.

High frequency stimulation (HFS) of the subthalamic nucleus (STN) is a well-established therapeutic approach for the treatment of late-stage Parkinson's disease. Although the underlying cause of this illness remains a mystery, changes in firing rate and synchronized activity in different basal ganglia nuclei have been related to its symptoms. Here we investigated the impact of STN-HFS on firing rate as well as correlated and oscillatory activity in the STN network in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned non-human primates by using simultaneous extracellular single-unit recordings. STN-HFS reduced (i) the firing rate of STN neurons, (ii) the oscillatory activity at an individual STN neuron level as well as (iii) the correlated and oscillatory activity between pairs of STN neurons, while contralateral rigidity was improved. A detailed analysis showed that the decrease of mean firing rate resulted from the resetting of firing probability to virtually zero by the stimulus pulse. Subsequently, STN neurons resumed their activity after a mean duration of 2.9 +/- 0.1 ms and their firing probability returned to baseline values approximately 7 ms after the onset of the stimulus pulse, the recovery of the firing probability being represented by a sigmoid function. Thus, the overall decrease of the mean firing rate resulted from the repetition of this dynamical process with a frequency of 130 Hz (interstimulus interval approximately 7.7 ms), allowing the neuron to fire with its baseline firing rate only for a very short period. Although the mechanisms underlying the desynchronization of neuronal activity in the STN network remain unclear, the resetting of STN neuron firing probability by the electrical stimulus would rather be expected to increase oscillatory activity at an individual neuron level as well as correlated and oscillatory activity between pairs of STN neurons. However, assuming the resetting of firing rate to be the consequence of a transient GABAergic inhibition through excitation of presynaptic GABAergic axon terminals, different recovery periods of STN neurons might delay the appearance of synchronized oscillations, particularly if they are not generated locally. In conclusion, our study provides new evidence that STN-HFS decreases oscillatory activity in the STN network. Although the exact relation between oscillatory activity and Parkinson's disease symptoms remains to be determined, the present results suggest that STN-HFS might at least partially exert its beneficial effects through the reduction of oscillatory activity in the STN network and consequently in the entire cortex-basal ganglia-cortex network.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2005

Continuous positive airway pressure for sleep-related breathing disorders in multiple system atrophy: long-term acceptance.

BACKGROUND AND PURPOSE: To assess the long-term acceptance of non-invasive nasal continuous positive air pressure (CPAP) in multiple system atrophy (MSA) patients with polysomnographic (PSG)-confirmed sleep apneas and/or nocturnal stridor. PATIENTS AND METHODS: Sleep-related breathing disorders were investigated by PSG in 22 MSA patients in whom stridor and sleep-related respiratory disturbances were clinically suspected. Patients in whom the first PSG disclosed either a sleep apnea/hypopnea index (AHI)> or =10 or stridor with or without apneas underwent a second PSG for CPAP titration. RESULTS: Three patients presented with an obstructive sleep apnea syndrome without stridor, whereas 15 patients presented stridor occurring alone or accompanied by apneas. Twelve patients pursued CPAP. Two severely disabled patients died a few days after CPAP initiation, and five discontinued CPAP because of discomfort. One patient died after 17 months of follow-up. Since the onset of CPAP, the four remaining patients reported more efficacious sleep and improved daytime alertness. These patients had significantly less severe disease at the time of CPAP initiation. Age, disease duration, the presence of sleep complaints, excessive daytime somnolence (EDS) and AHI did not account for CPAP compliance. CONCLUSION: The severity of motor impairment at the initiation of treatment appears to be the most significant limiting factor for CPAP long-term acceptance.

Aged↗
PubMed2005

Sleep duration and caffeine consumption in a French middle-aged working population.

OBJECTIVE/BACKGROUND: To explore the association between sleep duration and daily caffeine intake in a working population. Caffeine acutely disrupts sleep in the laboratory, but the inter-relations between sleep and caffeine intake in daily life are ill-known. METHODS: Questionnaire and diary based survey of 1498 persons from the GAZEL cohort of employees of the National Electricity and Gas Company (EDF-GDF) working in various locations in the Paris and South-West France areas. We analyzed total sleep time, our primary measure, and time in bed, both by sleep logs. We assessed daily intake of caffeine, consumption of alcohol and tobacco, use of hypnotics, and daytime somnolence, all by questionnaire. RESULTS: Multiple linear regression analysis did not find a significant relationship between total sleep time and daily caffeine intake less than 8 cups of coffee per day, after controlling for age, gender, alcohol intake, smoking status, and use of hypnotics. By contrast, time in bed was reduced as caffeine intake increased (beta=-0.125; P<0.001). Higher caffeine intake was not related to a higher daytime somnolence. CONCLUSION: Despite the well-known acute effects of caffeine on sleep, habitual use of up to 7 cups of coffee (or 600 mg of caffeine equivalent) per day was not associated with decreased duration of sleep.

Beverages↗
PubMed2005

Unusual nocturnal motor restlessness in a patient with spinocerebellar ataxia 3.

Video-polysomnographic monitoring of a female patient with spinocerebellar ataxia 3 (SCA-3) in whom rapid eye movement (REM) sleep behavior disorder was clinically suspected demonstrated recurrent episodes of unusual nocturnal motor restlessness occurring during non-REM sleep and severely disturbing both the patient and her bed partner's sleep. Even if nocturnal manifestations are common features of SCA-3 and increasingly recognized, such a case has never been reported before. We discuss this peculiar movement disorder as a particular manifestation of the wide spectrum of parasomnias occurring in such a rare neurodegenerative disease.

Adult↗
PubMed2005

Fatigue, sleep restriction and driving performance.

We ran a randomized cross-over design study under sleep-deprived and non-sleep-deprived driving conditions to test the effects of sleep restriction on real driving performance. The study was performed in a sleep laboratory and on an open French highway. Twenty-two healthy male subjects (age = 21.5 +/- 2 years; distance driven per year = 12,225 +/- 4739 km (7641 +/- 2962 miles) [mean +/- S.D.]) drove 1000 km (625 miles) over 10 h during five 105 min sessions on an open highway. Self-rated fatigue and sleepiness before each session, number of inappropriate line crossings from video recordings and simple reaction time (RT) were measured. Total crossings increased after sleep restriction (535 crossings in the sleep-restricted condition versus 66 after non-restricted sleep (incidence rate ratio (IRR): 8.1; 95% confidence interval (95% CI): 3.2-20.5; p < 0.001)), from the first driving session. The interaction between the two factors (conditionxtime of day) was also significant (F(5, 105) = 3.229; p < 0.05). Increasing sleepiness score was associated with increasing crossings during the next driving session in the sleep-restricted (IRR: 1.9; 95% CI: 1.4-2.4) but not in the non-restricted condition (IRR: 1.0; 95% CI: 0.8-1.3). Increasing self-perceived fatigue was not associated with increasing crossings in either condition (IRR: 0.95; 95% CI: 0.93-0.98 and IRR: 1.0; 95% CI: 0.98-1.02). Rested subjects drove 1000 km with four shorts breaks with only a minor performance decrease. Sleep restriction induced important performance degradation even though time awake (8h) and session driving times (105 min) were relatively short. Major inter-individual differences were observed under sleep restriction. Performance degradation was associated with sleepiness and not fatigue. Sleepiness combined with fatigue significantly affected RT. Road safety campaigns should encourage drivers to avoid driving after sleep restriction, even on relatively short trips especially if they feel sleepy.

Adolescent↗
PubMed2005

High-frequency stimulation in Parkinson's disease: more or less?

Deep-brain stimulation at high frequency is now considered the most effective neurosurgical therapy for movement disorders. An electrode is chronically implanted in a particular area of the brain and, when continuously stimulated, it significantly alleviates motor symptoms. In Parkinson's disease, common target nuclei of high-frequency stimulation (HFS) are ventral thalamic nuclei and basal ganglia nuclei, such as the internal segment of the pallidum and the subthalamic nucleus (STN), with a preference for the STN in recent years. Two fundamental mechanisms have been proposed to underlie the beneficial effects of HFS: silencing or excitation of STN neurons. Relying on recent experimental data, we suggest that both are instrumental: HFS switches off a pathological disrupted activity in the STN (a 'less' mechanism) and imposes a new type of discharge in the upper gamma-band frequency that is endowed with beneficial effects (a 'more' mechanism). The intrinsic capacity of basal ganglia and particular STN neurons to generate oscillations and shift rapidly from a physiological to a pathogenic pattern is pivotal in the operation of these circuits in health and disease.

Animals↗
PubMed2005

Fatigue, sleepiness, and performance in simulated versus real driving conditions.

STUDY OBJECTIVES: To determine whether real-life driving would produce different effects from those obtained in a driving simulator on fatigue, performances and sleepiness. DESIGN: Cross-over study involving real driving (1200 km) or simulated driving after controlled habitual sleep (8 hours) or restricted sleep (2 hours). SETTING: Sleep laboratory and open French Highway. PARTICIPANTS: Twelve healthy men (mean age +/- SD = 21.1 +/- 1.6 years, range 19-24 years, mean yearly driving distance +/- SD = 6563 +/- 1950 miles) free of sleep disorders. MEASUREMENTS: Self-rated fatigue and sleepiness, simple reaction time before and after each session, number of inappropriate line crossings from the driving simulator and from video-recordings of real driving. RESULTS: Line crossings were more frequent in the driving simulator than in real driving (P < .001) and were increased by sleep deprivation in both conditions. Reaction times (10% slowest) were slower during simulated driving (P = .004) and sleep deprivation (P = .004). Subjects had higher sleepiness scores in the driving simulator (P = .016) and in the sleep restricted condition (P = .001). Fatigue increased over time (P = .011) and with sleep deprivation (P = .000) but was similar in both driving conditions. CONCLUSIONS: Fatigue can be equally studied in real and simulated environments but reaction time and self-evaluation of sleepiness are more affected in a simulated environment. Real driving and driving simulators are comparable for measuring line crossings but the effects are of higher amplitude in the simulated condition. Driving simulator may need to be calibrated against real driving in various condition.

Adult↗
PubMed2005

[The anterior cingulate cortex in error detection and conflict monitoring. Unitary neuronal activity in monkeys].

Using a Stroop-like visuo-motor task in monkeys, we studied the unitary neuronal activity of the anterior cingulate cortex (ACC, CMAr : 24c) during error detection and conflict monitoring. A high percentage of cingular neurons modified their firing frequency during both attentional and evaluation periods. During the latter period, however, changes in discharge rates were always much more pronounced for erroneous responses than for successful movements that induced reward delivery. Moreover, some neurons responded more markedly to the warning stimulus when a previous trial failed In this case, the probability of a subsequent correct response increased. Such a neuronal apparatus could represent an error compensation system that serves to adapt a subject's behavioral response following an unfavorable and unexpected outcome. Abnormal activity of these neurons, which appear to take advantage of past errors, could contribute to the genesis of obsessive-compulsive disorders (OCD).

Animals↗