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Biomedical subjects

M Pottier

Publications and source records attributed to M Pottier.

At least 19 recordsLinked to original sources
PubMed1999

Residual effect of zolpidem 10 mg and zopiclone 7.5 mg versus flunitrazepam 1 mg and placebo on driving performance and ocular saccades.

RATIONALE: Studies report contradictory results concerning the residual effects of zolpidem and zopiclone. Moreover, residual effects of these compounds on healthy subjects have not yet been simultaneously assessed. OBJECTIVE: The present study with healthy subjects investigated the residual effects of zolpidem 10 mg and zopiclone 7.5 mg on driving performance and on ocular saccade and compared them to those under flunitrazepam 1 mg and placebo. METHODS: The study involved 16 subjects divided into two groups, a 9:00 a.m. group and a 11:00 a.m. group, in a balanced, double-blind, cross-over design. RESULTS: In the 9:00 a.m. group, zolpidem had no residual effects while zopiclone and flunitrazepam both impaired driving performance (P < 0.001 for both) and increased saccadic latency (P < 0.005; P = 0.052, respectively). Zopiclone impaired driving performance 5 times less than did flunitrazepam. In the 11:00 a.m. group, zolpidem and zopiclone had no residual effects, while flunitrazepam increased saccadic latency (P = 0.065) but did not impair driving performance. CONCLUSIONS: Zopiclone and flunitrazepam had residual effects in the first part of the morning, whereas zolpidem had no residual effects. The hierarchical character of the effects of the molecules differed according to the test administered. This is probably linked more to drug-induced specific alterations than to different sensitivities of the tests.

Adult↗
PubMed1998

Low intensity galvanic vestibulo-ocular reflex in normal subjects.

An electrical stimulation in man applied between the two mastoids could facilitate the distinction between labyrinthine and retrolabyrinthine lesions by stimulating directly the primary vestibular afferences. However, for this test to be really effective in current medical practice, the results obtained in normal subjects must be symmetrical and reproducible one day to another. The ocular responses induced by a constant electrical stimulation of 2.5 mA, applied between the two mastoids for 30 s (electrically evoked vestibulo-ocular reflex [EVOR]), in one direction and the other, were quantified in ten healthy subjects. Each subject was studied in two different sessions separated by 1 week. Horizontal eye movements were recorded in darkness by an infrared light reflection eye-tracking system. Slow-phase velocity and nystagmus frequency were about 20% higher when the cathode was on the right mastoid than when it was on the left mastoid. This directional preponderance (DP) displayed large individual differences between the two sessions. The reproducibility of the reflectivity (mean of right and left EVOR) was high (r about 0.8). The weak reproducibility of the DP makes the EVOR at weak intensity inadequate to evaluate unilateral vestibular hypofunction. On the other hand, because of the high reproducibility of reflectivity, the EVOR should be effective in detecting bilateral vestibular hypofunction. Moreover, because of the weak intensity of stimulation, no local anaesthesia is needed so the manoeuvre is easy to repeat in case of chronic diseases.

Adult↗
PubMed1992

SPEM impairment in drug-naive schizophrenic patients: evidence for a trait marker.

Smooth-pursuit eye movements (SPEM) were assessed in healthy subjects and in drug-naive, chronic, and residual schizophrenic patients. SPEM gain was found to be decreased in all the schizophrenic patients who also exhibited a significant increase in the rate of saccades. The frequency of square-wave jerks was the same in schizophrenic patients and normal controls, suggesting that the primary abnormality in schizophrenic patients was a low gain rather than a defect of the saccadic system. Patients were retested 1 month later, and stability of gain was high even in formerly drug-naive subjects who had been treated for 1 month with neuroleptic drugs. Altogether these results confirm the conclusions of most previous studies, extend them to drug-naive schizophrenic patients, and favor the hypothesis that SPEM impairment is a trait marker in schizophrenia.

Adult↗
PubMed1990

Maturation of peripheral nerves in preterm infants. Motor and proprioceptive nerve conduction.

The peripheral nerve maturation (proprioceptive and motor nerve conduction velocities (PNCV and MNCV] was studied in 3 groups of newborn babies. Two groups of premature babies (PT), studied when they reached the expected date of birth (group I, gestational age (GA) at birth 27-31 weeks, n = 13, group II, GA at birth 32-35 weeks, n = 9), were compared to 10 normal full-term newborns (FT). The MNCV of PT babies was similar to that of FT babies: group I 22.8 +/- 3.3 m/sec (X +/- S.D.), group II 24.9 +/- 4.3 m/sec, FT 25.7 +/- 3.9 m/sec. PNCV was significantly lower in group I (18.1 +/- 5.9 m/sec) than in group II (28.3 +/- 6.4 m/sec) and in FT babies (32.0 +/- 7.4 m/sec) (P less than 0.001). Such a delay in maturation could be partly responsible for the neurological impairment often observed in PT babies.

H-Reflex↗
PubMed1989

Maturation of peripheral nerves in preterm infants: proprioceptive and motor nerve conductions of tibial nerve.

Premature birth induces a profound change in the environmental factors affecting nerve maturation. The proprioceptive sensory and motor nerve conduction velocities (NCV) of the posterior tibial nerve, which reflect peripheral nerve maturation, have been measured in 3 groups of newborns. Two groups of premature (PT) babies, studied when they reached the expected date of birth (group I, gestational age (GA) at birth, 28-31 weeks, n = 8; group II, GA at birth, 32-35 weeks, n = 6) were compared to 9 normal full-term (FT) newborns. As previously shown, the motor NCV of PT babies at a post-conceptional age close to term is similar to that of FT newborns: group I, 22.70 +/- 2.95 m/s (mean +/- SD); group II, 25.90 +/- 4.61 m/s; FT, 25.48 +/- 4.09 m/s. The proprioceptive sensory NCV was significantly lower in group I (21.59 +/- 4.39 m/s) than in group II (31.89 +/- 4.15 m/s) and FT newborns (32.22 +/- 6.56 m/s) (p less than 0.01). Such a delay in maturation could be responsible for the subtle clinical dysfunctions often observed in PT babies.

Gestational Age↗
PubMed1985

[Changes in cortical evoked potentials in relation to cutaneous sensory thresholds. Application to a study of analgesic electrostimulation].

The potentials (EPs) evoked by cutaneous electric shock of increasing intensity and the corresponding sensitivity thresholds were studied in 25 healthy volunteers: analgesic electrical stimulation (AES) was performed on only 10 of these. The stimuli (0.5 msec; 0-140 V) applied in a random way with a needle electrode implanted in the horny layer of the tip of the middle finger can produce 4 sensations: initial awareness, pressure sensation, diffusion and pain. The EP recorded on the somatosensory areas had the typical somatosensory (SEP) morphology only at the pressure stage. At the pain thresholds, the response was a well-demarcated 'nociceptive' EP (NEP), with main components at P100, N140, P240. After 45 min of AES, the increase of the sensitivity thresholds was peculiarly pronounced for that of pain, homolaterally (80%) and contralaterally (45%) to the AES. With respect to the EPs, the NEP and especially its late waves showed a noteworthy reduction in amplitude, more significant on the homolateral side (66%) than on the contralateral one (50%), whilst the SEP was only slight modified. The evolution of the thresholds and of the EPs was followed for 45 min after cessation of AES and revealed a significant residual effect of comparable values for the two parameters.

Adult↗