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Biomedical subjects

D Commenges

Publications and source records attributed to D Commenges.

At least 73 records · Page 4Linked to original sources
PubMed1992

A longitudinal assessment of seizure outcome and overall benefit from 100 cortectomies for epilepsy.

Results of 100 cortical resections for 76 temporal, 23 frontal and one parietal lobe epilepsies were studied in terms of seizure relief and overall benefit. A non-homogenous Markov chain model was used to take into account both the intravariability of post-surgical outcome and the differences in duration of follow-up in a group of patients consecutively operated. The seizure free (SF) state was defined as no seizure in the previous five months at first follow up visit and none in the preceding 12 months at subsequent annual visits. For the whole of the population the SF probability was 82%, 66%, 61%, and 62% at six months, one year, two and five years respectively. A better outcome was found for temporal lobe epilepsy (SF probability: 68% at the fifth postoperative year) than for frontal lobe epilepsy (SF probability: 42% at the fifth postoperative year) with a statistically significant difference. Pre- and postoperative interictal signs and symptoms were classified according to their clinical significance: (a) mild handicap--symptoms recognisable but no interference with usual life, and (b) moderate or severe handicap--interference with some or all daily activities. The interictal state was considered more impaired after surgery than before in two situations: (a) either symptoms, absent before surgery, appeared in the postoperative period involving a moderate or severe handicap, or (b) symptoms present before surgery and answerable for a mild or moderate handicap that increased to involve a moderate or severe handicap respectively in the postoperative period. Surgery was considered a major benefit when two conditions were fulfilled-namely, a SF state and no deterioration of the interictal stage when compared with the preoperative period. The probability of obtaining such a benefit was 58%, 51%, 48% and 56% at six months, one year, two and five years respectively. The results suggest that surgery is an effective treatment for more than 50% of long lasting medically intractable epilepsies.

Adolescent↗
PubMed1992

The Paquid epidemiological program on brain ageing.

Paquid is an epidemiological study designed to gather and follow-up a cohort of 3,777 elderly subjects (65 years and older) living at home. In order to study normal and pathological brain ageing, these subjects were randomly chosen in the general population of 75 communities of Gironde and Dordogne, two administrative areas of South-Western France. The subjects were interviewed at home by trained psychologists and followed-up with the same procedure at 1, 3 and 5 years after the initial data collection. The identification of the demented cases is made with a two-stage design: the first stage is a systematic screening by the psychologists with application of the DSM-IIIR criteria and the second stage consists in a confirmation of the diagnosis by a neurologist according to the NINCDS-ADRDA criteria. Paquid is complemented by the study of a random sample of 357 subjects living in institutions in Gironde.

Activities of Daily Living↗
PubMed1992

Elimination of atrioventricular nodal reentrant tachycardia using discrete slow potentials to guide application of radiofrequency energy.

BACKGROUND: Ablation of the slow pathway has been performed to eliminate atrioventricular (AV) nodal reentrant tachycardia (AVNRT) either by a surgical approach or by using radiofrequency catheter technique guided by retrograde slow pathway activation mapping. From previous experience of midseptal and posteroseptal mapping, we were aware of the existence of peculiar slow potentials in most humans. Postulating their role in AVNRT, we studied these potentials and the effects of radiofrequency energy. METHODS AND RESULTS: Sixty-four patients (mean age, 48 +/- 19 years) with the usual form of AVNRT were studied. Slow, low-amplitude potentials were recorded when using the anterograde AV conducting system. Slow potentials occupied all (giving a continuum of electrograms) or some of the time between the atrial and ventricular electrograms. Their most specific patterns were their progressive response to increasing atrial rates, which resulted in a dramatic decline in amplitude and slope, a corresponding increase in duration, and a separation from preceding atrial potentials until the disappearance of any consistent activity. Slow potentials were recorded along a vertical band at the mid or posterior part of the septum near the tricuspid annulus. Radiofrequency energy applied at the slow potential site resulted in interruption of induced tachycardia within a few seconds and rendered tachycardia noninducible in all patients. A median of two impulses was delivered to each patient. In 69% of patients, postablation atrial stimulation cannot achieve a long atrial-His interval, which previously was critical for tachycardia induction or maintenance. No patient had AVNRT over a follow-up period of 1-16 months, and all had preserved AV conduction. In all except two patients, the PR interval was unchanged. In 47 patients, long-term electrophysiological studies confirmed the efficacy of ablation and the nonreversibility of results by isoproterenol; however, echo beats remained inducible in 40% of patients. CONCLUSIONS: An area showing slow potentials is present at the perinodal region in humans. In patients with AVNRT, application of radiofrequency energy renders tachycardia noninducible through the preferential modification of the anterograde slow pathway. With present clinical methods, the exact origin and significance of these physiological potentials cannot be specified.

Cardiac Pacing, Artificial↗
PubMed1992

Occupation during life and memory performance in nondemented French elderly community residents.

Using data obtained during the baseline screening of the PAQUID cohort, an epidemiologic study on brain aging conducted in the Bordeaux area of France, we studied the relationship between lifetime occupation and memory performance in visual recognition (Benton Visual Retention Test; BVRT) and verbal induced recall (Wechsler Paired Associates Test; WPAT) in 2,720 elderly community residents. Occupational category was strongly correlated with poor memory performance for both the BVRT and the WPAT. Independent of the educational level, the risk of having poor memory performance was two to three times greater for farmers, domestic service employees, and blue-collar workers than for professionals/managerials. Occupational category should be taken into account in future cross-national studies on brain aging.

Aged↗
PubMed1992

[Bone risk of hormone-suppressing therapy in differentiated thyroid epithelioma. Study by dual photon absorptiometry].

A decreased bone mineral density is a well known complication of thyrotoxicosis. If bone is also adversely affected by a subclinical hyperthyroidism is still debated. Such a situation is deliberately induced for treatment of thyroid differentiated carcinoma. We compared bone mineral measurements in case of thyroid carcinoma exposed to prolonged suppressive hormonal treatment (288 patient year, LT3 in 87%) and in age and weight matched controls. We did not find any difference in both sexes between the two populations in term of fracture rate and vertebral mineral density measured by dual photon absorptiometry, nor any influence of gonadal status in women.

Absorptiometry, Photon↗
PubMed1991

Comparative efficiency of a survival-based case-control design and a random selection cohort design.

Ambidirectional studies are useful when information about disease status is available on a cohort but a risk factor has still to be recorded. An example is the study of the influence of HLA phenotypes on the progression of HIV carriers towards AIDS. An ambidirectional design is proposed in which the cases and controls are defined by the survival duration of the subjects; it includes as special cases some other ambidirectional designs. Its efficiency is compared with that of a random selection cohort design both analytically and by computer simulation. It is shown that when the size of the cohort is large, appreciable gains in power can be achieved by this type of design even when there is no censoring.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[The Paquid research program on the epidemiology of dementia. Methods and initial results].

Paquid is an epidemiological study designed to gather and follow up a cohort of 4,000 elderly subjects (65 years and older) living at home in order to study normal and pathological brain aging. These subjects were randomly chosen in the general population of 75 communities of South-Western France. We present the results of the data collected from 2,792 subjects on the prevalence and the correlates of clinically diagnosed dementia. The DSM III criteria for dementia were met by 101 subjects (3.62 p. 100). These cases were reviewed by a neurologist to confirm the diagnosis and to determine the cause of dementia using the NINCDS-ADRDA criteria. Forty-three subjects were classified as probable Alzheimer's disease; 8 as possible Alzheimer's disease; 5 as vascular dementia; 5 as Parkinson's disease with dementia; 2 as alcoholic dementia; 2 as "dementified psychosis"; and 1 unclassified. Fifteen patients refused to be examined by the neurologist, 18 were false-positives, and 2 died before the neurologists visit. Using the NINCDS-ADRDA criteria, the prevalence of dementia was as low as 1.6 p. 100. The prevalence of probable Alzheimer's disease decreased dramatically as educational level increased, lung 5.4 p. 100 for subjects with no education, 1.7 p. 100 for subjects with grade school level, 0.4 p. 100 for subjects with high school level and 0.4 p. 100 for subjects with university degrees. The relationship between dementia and educational level is still controversial in the literature. In this study the sample was large and randomly selected; all the demented cases fulfilled the NINCDS-ADRDA criteria. This suggests that educational level is indeed an important correlate of dementia in the French elderly community.

Aged↗
PubMed1990

Validity of the Mini-Mental State examination as a screening instrument for cognitive impairment and dementia in French elderly community residents.

A survey was made of 2,792 subjects aged 65 and older living in the community of Gironde (South-Western France). The predictive value of the Mini-Mental state examination (MMS) as a screening instrument for the detection of cognitive impairment was tested against DSM-III criteria for dementing syndromes. Of the 2,792 subjects who consented to participate in the study, 101 met the DSM-III criteria for dementia, giving a 3.62% prevalence rate. With an MMS threshold of 24, the sensitivity was 100%, the specificity was 78%, and the positive predictive value was equal to 15%. Using the same MMS threshold, 572 subjects (85%) were false-positive for the diagnosis of dementia. A multiple logistic regression analysis revealed that age, sex, depressive symptomatology and educational level were independently correlated with false-positive cases of the MMS. Several issues are raised for using the MMS as the only screening instrument for cognitive impairment in elderly community residents.

Aged↗
PubMed1989

[Electrophysiologic study of syncope. Prediction of results].

In order to determine the factors predictive of dysrhythmia or disorders of conduction, 20 variables were analysed retrospectively in 201 patients who had undergone electrophysiological exploration. The electrophysiological abnormalities found to be significant were major sinus dysfunction (corrected post-stimulation atrial pause longer than 1 second), subnodal block (HV interval greater than 70 ms) or induction of sustained monomorphous ventricular tachycardia. The electrophysiological exploration gave abnormal results in 50 patients (25 per cent) with ventricular tachycardia in 36, subnodal block in 11 and sinus dysfunction in 5. Multivariate analysis brought out 4 independent variables that were predictive of electrophysiological study results. Presence of a cardiac disease (P less than 0.001), male sex (P less than 0.001), bundle branch block (P = 0.002) or injury consecutive to a syncope (P = 0.003) were associated with an abnormal exploration. The odd ratio of an abnormal electrophysiological exploration in the presence of a variable as compared with the reverse situation was 10, 6.25, 3.8 and 5 respectively. Postprandial syncopes were associated with a negative exploration (P = 0.06). Combining these variables and using a logistic regression model would provide an estimate of the probability of a positive or negative electrophysiological study. The selection of a high probability group would then indicate whether or not an electrophysiological study would be required.

Aged↗
PubMed1989

Loss of maternal measles antibody during infancy in an African city.

Measles epidemics with 20% of the cases under nine months of age continue to occur in Brazzaville, Congo, even though measles vaccination coverage was 77% in the 12- to 23-month age group in 1986. In order to estimate the duration of passive immunity against measles, we conducted a serologic survey of infants aged 2 to 9 months. Measles antibody was measured from capillary blood with the plaque inhibition test. An antibody titre of 40 milli-International Reference Units per ml of serum (mIRU/ml) or less was defined as seronegative. Among the 252 infants studied, the proportion with detectable antibody dropped from 95.8% at 2 months of age to 48.5% at 4 months of age, and to 8.2% in the 7-8 month age group. A simple logistic model with age as the only variable provided an excellent fit to the observed values. Between the ages of 8 and 28 weeks, there was an almost steady decline of approximately 4.7% per week in the proportion of infants who were seropositive. These findings suggest that loss of maternal measles antibody during infancy might be faster than reported in other African populations. Giving measles vaccine to infants before the age of nine months currently recommended by the Expanded Programme on Immunization may be useful in some populations. Further studies of seroconversion and impact on measles are needed.

Age Factors↗
PubMed1989

Evaluation and simplification of the World Health Organization clinical case definition for paediatric AIDS.

The World Health Organization (WHO) clinical case definition for paediatric AIDS was tested during a 1-month period on 221 consecutive hospitalized children in Kigali, Rwanda. Relevant clinical features not included in the WHO case definition were also evaluated. Thirty-four out of the 221 children (15.4%) were HIV seropositive. Although the specificity of the WHO case definition was high (92%), the sensitivity and the positive predictive value (PPV) were low (41 and 48%, respectively). The following individual signs had a PPV at least equal to the complete WHO case definition: chronic diarrhoea (47%), respiratory distress secondary to lower respiratory tract infection (50%), oral candidiasis (53%), parotitis (67%), generalized lymphadenopathy (88%), and herpes zoster infection (100%). When logistic regression analysis was done on the nine variables included in the WHO case definition, confirmed maternal infection was the best predictive variable for HIV seropositivity in children (P less than 10(-5). We further excluded the serological status of the mother from the analysis and performed a stepwise logistic regression analysis on the 18 clinical signs and symptoms for which information had been collected. Those signs and symptoms contributing the most to the regression were: respiratory distress, chronic diarrhoea and generalized lymphadenopathy. Based on these findings, we propose a simplified clinical case definition for paediatric AIDS in Africa with better sensitivity, specificity and PPV than the WHO case definition. Further work is needed using this approach to develop case definitions useful for epidemiological surveillance and for case management.

Acquired Immunodeficiency Syndrome↗
PubMed1989

A strategy for analysing multiple risk factors with application to cervical pain syndrome.

When studying the possible effects of several factors in a given disease, two major problems arise: (1) confounding, and (2) multiplicity of tests. Frequently, in order to cope with the problem of confounding factors, models with multiple explanatory variables are used. However, the correlation structure of the variables may be such that the corresponding tests have low power: in its extreme form this situation is coined by the term "multicollinearity". As the problem of multiplicity is still relevant in these models, the interpretation of results is, in most cases, very hazardous. We propose a strategy--based on a tree structure of the variables--which provides a guide to the interpretation and controls the risk of erroneously rejecting null hypotheses. The strategy was applied to a study of cervical pain syndrome involving 990 subjects and 17 variables. Age, sex, head trauma, posture at work and psychological status were all found to be important risk factors.

Adult↗
PubMed1988

Prevalence and risk factors of recurrent cervical pain syndrome in a working population.

The prevalence and risk factors of recurrent cervical pain syndrome (CPS) was studied in 990 workers examined while undergoing their systematic annual visit of occupational medicine. A prevalence rate of 10.2% was obtained. Using a tree-structured logistic regression analysis, a strong association between age, sex, previous head trauma extension of the neck and strenuous muscular activity during work, and the risk of recurrent CPS was obtained. Finally, an inverse association between strenuous muscular activity during leisure time and the risk of recurrent CPS was found.

Adult↗
PubMed1988

Predictors of non-bedridden survival in dementia.

The present study examined non-bedridden survival in 105 patients diagnosed as demented (Alzheimer's disease, multi-infarct dementia, mixed dementia) in a neurological ward. Follow-up observations were made. During the first year, the cumulative mortality rate was 69% compared to a rate of 44% in the second year. The initial disability stage, as assessed by the Dementia Disability Scale, was found to be the only significant predictor of non-bedridden survival. The type of dementia, age, type of diagnosis, and post-hospitalization placement in an institution have not been found to be significant predictors of this evolution.

Adult↗
PubMed1988

[Predictive factors of the therapeutic result in the prevention of auricular fibrillation. Role of electrophysiological studies].

A population of 50 patients suffering from paroxysmal attacks of atrial fibrillation was studied prospectively to evaluate the prognostic value of 20 variables: 6 clinical variables: sex, age, cardiopathy, number of arrhythmic attacks, "vagal" triggering, failure of class IA antiarrhythmic agents; 3 echocardiographic variables: left ventricular diastolic diameter and percentage of fibre shortening, left atrial diameter; 6 basic electrophysiological data: threshold, refractory periods at 110 and 150/min, modalities of induction of a sustained arrhythmia; 4 results observed with an infusion of flecainide in doses of 2 mg/kg: arrest or persistence of the arrhythmia, whether or not it could be reinduced and value of refractory periods; doses of flecainide administered orally. With a mean +/- SD follow-up period of 7.7 +/- 7.3 months, preventive treatment with flecainide 233 +/- 7 mg failed in 16 patients (32 per cent) and succeeded in 34 patients (68 per cent). Analysis of Kaplan-Meier curves and use of Cox's multidimensional model showed that two electrophysiological data were of prognostic value: atrial effective refractory period, and non-inducibility of the arrhythmia after intravenous administration of flecainide. Thus, the probability of failure increases with the refractory period value and decreases with the non-inducibility of the arrhythmia.

Aged↗
PubMed1986

The formulae-relating slopes, correlation coefficients and variance ratios used to determine stimulus- or movement-related neuronal activity.

When recording single neuron discharge in an animal during the performance of a conditioned task, the functional interpretation of any change in neuronal activity after the conditioned stimulus but before the conditioned task is difficult. So far, such changes have been described as either stimulus- or movement-related. One way of classifying these two types of response has been to use the slope and correlation coefficient between the response latency and the behavioural reaction time. We show that this method is poor and propose a more valid approach.

Animals↗
PubMed1986

A program for analysing single neuron activity by methods based on estimation of a change-point.

A program for analysing the sequences of discharge of a single neuron is presented. This program performs the following tasks: it tests if there is a neuronal response after a stimulus, it estimates the response latency and, in the case of an experiment with a conditioned movement, it estimates the onset of the movement and gives indications about the functional role of the neuron by analysing the variances of the stimulus-response and response-movement times. The methods used have been developed by the authors and are based on the estimation of a change point. The basic methods are published elsewhere but some novelties are presented here, in particular a robust estimator of a variance ratio.

Action Potentials↗