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Biomedical subjects

B Dan

Publications and source records attributed to B Dan.

At least 19 recordsLinked to original sources
PubMed2002

Electrophysiological assessment of the effect of intrathecal baclofen in spastic children.

OBJECTIVES: To evaluate the effect of intrathecal baclofen in a group of spastic children using electrophysiological procedures described in adults. METHODS: Six children (aged 1-14 years) with severe spasticity of various aetiologies underwent transcranial magnetic stimulation, H reflex and flexor reflex studies before and after intrathecal injection of baclofen. Ashworth scale was used for clinical evaluation of spasticity. RESULTS: Motor evoked potentials, present in two patients before baclofen, were preserved after injection. Before baclofen, H reflex was present in 5 patients (H(max)/M(max) from 0.23 to 0.84) and absent in one who had infantile neuroaxonal dystrophy. After baclofen, it was absent in 4 patients and markedly reduced in one. Surface of flexor reflex significantly decreased after baclofen (P=0.01), while threshold significantly increased (P=0.003). CONCLUSIONS: In spastic children, the action of baclofen on spinal pathways may be quantified by the same electrophysiological procedures as in adults. This approach may contribute to select optimal dosage.

Adolescent↗
PubMed2002

Contraception of women with intellectual disability: prevalence and determinants.

The contraception of women with intellectual disability (ID) is a major concern for caregivers. However, the prevalence of contraception and the frequency of use of different methods (e.g. sterilization) remain generally unknown. Moreover, indications specific to women with ID are controversial. The present authors conducted a population-based study among 97% of the women with ID aged between 18 and 46 years attending government-funded facilities in Brussels and the nearby province of Walloon Brabant in Belgium. Out of 397 subjects, 40.8% did not use any contraceptive method, 22.2% were sterilized, 18.4% used an oral contraceptive agent, 17.6% used depotmedroxyprogesterone acetate and 1% used an intrauterine device. These figures differ widely from those of the general Belgian population. Binary logistic regression for 'contraceptive utilization' showed the strong influence of institutional factors such as sleeping environment (i.e. institutional or parental), sexual relationship policy and contraception policy. Having or having had a boyfriend is also correlated with a stronger probability of contraceptive use. Other factors have a smaller influence (e.g. a milder level of ID). Very few factors, none of which are medical, are correlated with an increased use of a specific method. The present results are discussed in the light of the general medical application of contraception and the commonly assumed specific indications for women with ID.

Adult↗
PubMed2001

Interference with withdrawal signs of naloxone-induced opiate withdrawal under anesthesia is anesthetic-specific in opiate-dependent rats.

We hypothesized that interference of opiate antagonist-precipitated withdrawal signs under anesthesia is anesthetic-specific. Three groups of morphine-dependent rats were compared in different experimental conditions using a protocol of rapid withdrawal induction by an antagonist under anesthesia. We observed that ketamine and midazolam have different effects on the expression of withdrawal. This brings specific insights into the pharmacological basis of therapy with induction of opiate antagonist.

Anesthesia, General↗
PubMed2001

Early emergence of temporal co-ordination of lower limb segments elevation angles in human locomotion.

We analysed the co-ordination of the elevation angles of the thigh (alpha(t)), shank (alpha(s)) and foot (alpha(f)) during walking in 19 adults and 21 children (aged 11--144 months), including the very first unsupported steps in four. Cross-correlation functions (CCF) maturation of pairs of elevation angles was quantified by a global error parameter (Et((CCF))) reflecting the difference between particular CCF value of toddlers and mean adult value (Ea((CCF))). During the very first step, Et((CCF)) could be five times higher than Ea((CCF)). With walking experience, Et((CCF)) for both alpha(t)-alpha(s) and alpha(s)-alpha(f) pairs evolved following a biexponential profile, with a fast time constant below 6 months. Adult-like CCF parameters were reached earlier for alpha(s)-alpha(f) than alpha(t)-alpha(s), indicating disto-proximal maturation of the temporal co-ordination of the lower limb segments in human locomotion.

Adult↗
PubMed2001

Impaired emotional facial expression recognition in alcoholism compared with obsessive-compulsive disorder and normal controls.

Emotional facial expression (EFE) decoding skills have been shown to be impaired in recovering alcoholics (RA). The aim of the present study is to replicate these results and to explore whether these abnormalities are specific to alcoholism using two control groups: non-patient controls (NC) and patients with obsessive-compulsive disorder (OC). Twenty-two alcoholic patients at the end of their detoxification process (RA) were compared to 22 OC and 22 NC matched for age, sex and education level. They were presented with 12 photographs of facial expressions portraying different emotions: happiness; anger; and fear. Each emotion was displayed with mild (30%) and moderate (70%) intensity levels. Each EFE was judged on 8 scales labeled happiness, sadness, fear, anger, disgust, surprise, shame and contempt. For each scale, subjects rated the estimated intensity level. RA were less accurate in EFE decoding than OC and NC, particularly for anger and happiness expressions. RA overestimated the emotional intensity for mild intensity level expressions compared with both OC and NC while no significant differences emerged for moderate intensity level expressions. Deficits in EFE decoding skills seem to be specific to RA when compared with OC. Comparison with other psychopathological groups is still needed. Possible consequences of EFE decoding deficits in RA include distorted interpersonal relationships.

Adult↗
PubMed2001

Development of a kinematic coordination pattern in toddler locomotion: planar covariation.

The purpose of this study is to analyze the coordination patterns of the elevation angles of lower limb segments following the onset of unsupported walking in children and to look for the existence of a planar covariation rule as previously described in adult human locomotion. The kinematic patterns of locomotion were recorded in 21 children (11-144 months of age) and 19 adults. In 4 children we monitored the very first unsupported steps. The extent to which the covariation of thigh, shank, and foot angles was constrained on a plane in 3D space was assessed by means of orthogonal regression and statistically quantified by means of principal component analysis. The orientation of the covariation plane of the children was compared with the mean value of the adults' plane. Trunk stability with respect to the vertical was assessed in both the frontal (roll) and sagittal (pitch) planes. The evolution with walking experience of the plane orientation and trunk oscillations demonstrated biexponential profiles with a relatively fast time constant (< 6 months after the onset of unsupported locomotion) followed by a much slower progression toward adult values. The initial fast changes of these walking parameters did not parallel the slow, monotonic maturation of anthropometric parameters. The early emergence of the covariation plane orientation and its correlation with trunk vertical stability reflect the dynamic integration of postural equilibrium and forward propulsion in a gravity-centered frame. The results support the view that the planar covariation reflects a coordinated, centrally controlled behavior, in addition to biomechanical constraints. The refinement of the planar covariation while morphological variables drastically change as the child grows implies a continuous update of the neural command.

Aging↗
PubMed2001

Anterior spinal artery syndrome after aortic surgery in a child.

Anterior spinal artery syndrome is rare in children. In adults, where it is observed most frequently after resection of thoracoabdominal aortic aneurysms, spinal magnetic resonance imaging is considered the first-line investigation to confirm the clinical diagnosis. A 3-year-old male who presented with this syndrome after palliative cardiac surgery for a complex cardiac malformation associated with aortic coarctation is presented. Clinical diagnosis of anterior horn cell impairment below the L2 level was confirmed by electromyography and F-wave studies. Sparing of dorsal sensory tracts was documented by normal somatosensory-evoked potentials, which confirmed the anterior localization of the lesion. Spinal magnetic resonance imaging performed on day 15 and day 105 after surgery was normal. Neurologic deficits, including flaccid paraplegia, remained stable except for the reappearance of patellar reflexes on day 83. Neurophysiologic conduction studies were consistent with lower motoneuron loss. In this patient, magnetic resonance imaging was less sensitive in demonstrating spinal cord lesion than clinical neurophysiology. Somatosensory-evoked potentials failed to detect the insult. Prevention may therefore require other neurophysiologic monitoring techniques.

Anterior Spinal Artery Syndrome↗
PubMed2001

Distinct multi-joint control strategies in spastic diplegia associated with prematurity or Angelman syndrome.

Spastic diplegia is commonly due to periventricular leucomalacia associated with premature birth. It is also a feature of Angelman syndrome (AS), a neurogenetic disorder with developmental delay, absent speech and mirthful behaviour. We studied the kinematics and kinetics of the squatting movement and associated electromyographic (EMG) activities in 20 children with spastic diplegia associated with periventricular leucomalacia (SDPL) or AS and 18 unimpaired children. While movement of normal subjects consisted of vertical translation of most body segments, the movement of SDPL children was operated around the fixed knee with backward shift of the hip, and AS children performed a forward flexion of the trunk over the thigh. Trunk stability was correlated with movement velocity in both pathological groups. In normal subjects, anticipatory EMG pattern consisted of silencing of hamstring muscle tonic activity prior to movement onset. This deactivation was not present in spastic diplegia. In SDPL, anticipatory overactivation of ankle joint actuators was recorded and tonic co-contraction persisted throughout the movement. In AS, rhythmic EMG bursting was seen during the movement. Shoulder, hip and knee trajectories in the sagittal plane showed marked within-group stereotypies in orientation, shape and length. The patterns in both pathological groups were therefore distinctive. We speculate that they reflect corticospinal impairment in SDPL and combined corticospinal and cerebellar dysfunction in AS.

Angelman Syndrome↗
PubMed2001

Cerebral dysplasias: reviewed from a neurophysiological perspective.

Improvements in neuroimaging techniques have highlighted the role of cerebral dysplasia in developmental disorders and in epilepsy. The current classification is founded on the presumed timing of the first insult as deduced from the imaging appearances. Although clinical neurophysiological findings are often non-specific, several unusual patterns have been reported in association with certain types of malformation. These include the high amplitude rhythmic activities of lissencephaly, and focal rhythmic spikes. In this general review, we describe the electroence-phalographic and evoked potential findings in a wide range of cerebral dysplasias, including our personal experience of rare conditions such as Ramer-Lin syndrome. We focus on their role in assessment and on potential insights into pathophysiology.

Brain Mapping↗
PubMed2001

Deficits in recognition of emotional facial expression are still present in alcoholics after mid- to long-term abstinence.

OBJECTIVE: Emotional facial expression (EFE) decoding skills play a key role in interpersonal relationships. Decoding errors have been described in several pathological conditions, including alcoholism. The aim of this study was to investigate whether EFE decoding skill deficits persist after abstention from alcohol of at least 2 months. METHOD: Alcoholic patients abstinent for at least 2 months (n = 25) were compared with 25 recently detoxified patients and with 25 normal controls matched for age, gender and educational level. Subjects were presented with 40 photographs of facial expressions portraying happiness, anger, sadness, disgust and fear. Each emotion was displayed with neutral, mild, moderate and strong emotional intensity. Each facial expression was judged successively on eight scales labeled happiness, sadness, fear, anger, disgust, surprise, shame and contempt. For each scale, subjects rated the estimated intensity level. A complementary scale assessed the self-estimated difficulty in performing the task. RESULTS: Recently detoxified alcoholics were significantly less accurate than controls, making more EFE labeling errors and overestimating the intensity of the portrayed emotions. Deficits in decoding accuracy for anger and disgust were present in mid- to long-term abstinent patients; intensity overestimation was present in the former and absent in the latter. CONCLUSIONS: Deficits in decoding accuracy for anger and disgust, and to a lesser degree sadness, persist with an abstinence of 2 months and beyond. Right frontotemporal regions and cingulate could be implicated. These deficits may contribute to the social skills deficits frequently encountered in alcoholic patients.

Adult↗
PubMed2001

[Postinfectious hemicerebellitis].

The clinical signs of cerebellitis are usually bilateral and symmetrical. We report the case of a 9-year-old girl who presented with acute hemiataxia and flaccid hemiparesis associated with a lesion in the ipsilateral cerebellar cortex two weeks after a viral upper respiratory tract infection. The clinical outcome was good without treatment. Imaging follow-up showed hemiatrophy of the cerebellar cortex.

Cerebellar Diseases↗
PubMed2000

Previous anesthesia can temporarily overshadow the expression of a withdrawal syndrome in opiate dependent rats.

We hypothesized that induction of opiate antagonist-precipitated withdrawal under anesthesia can decrease the expression of later withdrawal signs. Three groups of morphine-dependent rats were compared in different experimental conditions of withdrawal precipitation using naloxone. We showed that anesthesia can temporarily overshadow the expression of withdrawal signs, but that some signs can be delayed and increased in intensity. This can be explained by a parallel and temporary effect of anesthesia on arousal and pain threshold. This carries important implications on the use of anesthesia in detoxification procedures.

Analysis of Variance↗
PubMed2000

Factors influencing the determination of arousal thresholds in infants - a review.

Objective: To review the major confounding factors that influence the determination of arousal thresholds in infants.Review of confounding factors: The determination of arousal thresholds in infants measures their arousability from sleep. The evaluation is influenced by various conditions. The infant's arousability is decreased by maternal factors, such as exposure to cigarette smoke, alcohol, illegal drugs or medications during gestation or breastfeeding. The levels of arousal thresholds also depend on the age of the infant and on experimental conditions, such as previous sleep deprivation, type of arousal challenges, time of administration of the arousal challenge, sleep stage, body position, room temperature, use of a pacifier, bed sharing, or type of feeding. In addition, spontaneous arousals can occur and modify the infant's response to external arousal challenges.Conclusions: Factors known to modify infants' arousability from sleep should be controlled during studies designed to determine arousal thresholds.

Journal Article↗
PubMed2000

Effect of intrathecal baclofen on gait control in human hereditary spastic paraparesis.

The covariation between thigh, shank and foot elevation angles during locomotion was analysed by means of orthogonal planar regression in a patient with pure hereditary spastic paraparesis before and after an intrathecal bolus of baclofen and in seven healthy subjects. The size, shape and spatial orientation of the loop defining patient's planar covariation (thigh angle vs. shank angle vs. foot angle) significantly differed from the controls' before baclofen, whereas these features resumed normal characteristics after baclofen injection. This shows that alteration of the control of phase coupling for the co-ordination of lower limb segments in human gait by increased spinal reflexes can be reversed by intrathecal baclofen injection.

Adult↗
PubMed2000

Connatal Pelizaeus-Merzbacher disease in two girls.

We report the clinical, radiological and electrophysiological signs in two unrelated girls with the connatal form of Pelizaeus-Merzbacher disease (PMD). MRI plays an important role in the diagnosis, demonstrating the virtual absence of myelination. PMD is classically described as an X-linked leukodystrophy. Our two cases reinforce the hypothesis of a possible autosomal recessive transmission of the connatal form of PMD in some families, as recently presented.

Diagnosis, Differential↗
PubMed2000

Peri-optic nerve infiltration during leukaemic relapse: MRI diagnosis.

BACKGROUND: A 10-year-old boy with a history of acute lymphoblastic leukaemia (ALL), but without previous evidence of central nervous system involvement, presented with seizures 3 years after complete remission. MATERIALS AND METHODS: MRI showed bilateral enlargement of the optic nerves despite normal ophthalmological examination. RESULTS: Only the third cerebrospinal fluid examination showed 2 % blasts without concomitant bone-marrow infiltration. Enlargement of the optic nerves was consistent with bilateral leukaemic peri-optic nerve infiltration. The appearances returned to normal after chemotherapy. CONCLUSION: The optic nerves are a potential site of relapse in patients with systemic and meningeal ALL, even in the absence of ophthalmological signs.

Child↗