Statistical description of the Mini-Mental State Examination for French elderly community residents. Paquid Study Group

The distribution of total Mini-Mental State Examination (MMSE) scores, individual items, and groups of items were studied in French elderly community residents from a random sample of 2727 subjects. Serial seven, recall three objects, and copy pentagons had the lowest percentage of correct responses, while orientation to place, naming two objects, and three objects registration had the highest percentage of correct responses. The structure of correlation of the items was studied using Principal Components Analysis. The projection of the items on the first axis reflects the tendency of the items to vary in the same direction and is compatible with the fact that the MMSE items are all indicators of the same concept: cognitive performance. The second and third axes identify clusters of highly correlated variables and provide support for the internal validity of the MMSE score for a French population. The full MMSE score seems to be a valid instrument for the evaluation of cognitive performance in community-based elderly residents.

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.

Electrogram patterns predictive of successful catheter ablation of accessory pathways. Value of unipolar recording mode

BACKGROUND

Transcatheter electrical ablation has been used in the treatment of arrhythmias, and most experience has been obtained by ablating the normal atrioventricular conduction system. Less information is available on ablation of atrioventricular accessory pathways.

METHODS AND RESULTS

Catheter ablation of overt accessory pathways was attempted in 135 patients with 142 distinct pathways, including 21 right parietal or anteroseptal, 47 posteroseptal, and 74 left lateral pathways. We sought to identify the type and value of electrophysiological parameters associated with successful ablation outcome. For this purpose, the unipolar recording mode was used in addition to bipolar anterograde and retrograde parameters. With a mean follow-up of 16 +/- 6 (mean +/- SD) months, fulguration was successful in eliminating preexcitation in 129 patients (96%), including all seven with two distinct accessory pathways. The first ablation attempt was successful in 110 patients, and two or more attempts were performed in 25 patients. Bipolar electrograms associated with success of fulguration showed a shorter atrioventricular conduction time (40 +/- 13 versus 53 +/- 17 msec, p less than 0.0001) and an earlier main ventricular deflection relative to delta wave onset (-1.7 +/- 10 versus 5 +/- 7 msec, p less than 0.001) than electrograms associated with unsuccessful outcome. The only parameter dealing with retrograde conduction (i.e., ventriculoatrial conduction time during reciprocating tachycardia) was not predictive (86 +/- 17 versus 93 +/- 17 msec). Neither was the atrial to ventricular electrogram amplitude ratio. Two unipolar parameters were found to be predictive of successful outcome: 1) The three different patterns PQS, P-QS, P-rS of unipolar waves recorded at the annulus were associated with respective success rates of 97%, 78%, and 55% (p less than 0.001). 2) Intrinsic deflection timing occurred -4 +/- 8 and 6 +/- 7 msec relative to delta wave onset in successful attempts and in failures, respectively (p less than 0.001). Logistic regression analysis revealed a single independent factor predictive of success, the unipolar pattern (p = 0.03), with an odds ratio of 7:1 (PQS pattern versus P-rS pattern). In the group of 18 patients who underwent a first unsuccessful but second successful attempt, comparison of electrograms revealed no difference in the ventriculoatrial conduction time but a significant improvement in anterograde parameters and unipolar pattern distribution.

CONCLUSIONS

Some distinctive electrogram patterns concerning anterograde conduction are associated with success of accessory pathway fulguration. The unfiltered unipolar recording mode (PQS pattern) contributes significantly to optimizing the accuracy of accessory pathway localization.

Dietary vitamin A, beta carotene and risk of epidermoid lung cancer in south-western France

This hospital-based case-control study was designed to investigate the association of low dietary vitamin A and beta carotene consumption with epidermoid lung cancer. Cases were patients with histologically confirmed epidermoid lung cancer diagnosed in six selected hospitals of southwestern France in 1983-84. Controls were selected from patients admitted to the same hospitals during the same period with diagnoses other than cancer. Cases and controls were matched for sex, age, place of residence, occupation, professional exposure to carcinogens, tobacco and alcohol consumption. A total of 106 cases of epidermoid lung cancer and 212 controls were interviewed on their typical weekly intake of 80 food items rich in preformed vitamin A and beta carotene. Index measures of the vitamin A and beta carotene daily intakes were computed for each individual patient and expressed in retinol equivalent (RE). A statistically significant odds ratio (OR) was found for preformed vitamin A (OR = 4.3; 95% CI: 2.5-7.3) with the threshold of 1,000 RE. A similar result was found for beta carotene with the same threshold (OR = 4.1; 95% CI: 2.3-7.4). Using the conditional logistic regression, consumption of preformed vitamin A and consumption of beta carotene were significantly and independently associated with epidermoid lung cancer. While confirming the protective role of beta carotene against epidermoid lung cancer, this study also shows that preformed vitamin A might have a distinct and important protective effect.

Telematics: a new tool for epidemiological surveillance of diarrhoeal diseases in the Aquitaine sentinel network

A sentinel health information system using telematics and a network of general practitioners was set up in Aquitaine in south western France in 1986. Among the health problems under surveillance was acute diarrhoea. Data for each patient who fulfilled the usual case definition for acute diarrhoea were reported by general practitioners using home terminals (Minitels) connected to a central computer by telephone. Over one year 2234 cases of diarrhoea were reported, the incidence varying from 0.8 to 1.5 cases per doctor per week. Seasonal variations in incidence were observed, with peaks in the winter and in the summer. Only 379 (17%) episodes of diarrhoea were classified as severe, and these patients consulted their general practitioners earlier than patients whose diarrhoea was less severe. Foreign travel was rarely found in the patients' histories, but clusters of cases were found in communities (4.6%) and in families (22.3%). The advantages of this system were easy reporting and immediate feedback, but it was difficult to extrapolate the data, and the system was inadequate for intervening in outbreaks of diarrhoeal disease. Our knowledge of diarrhoeal diseases in south west France improved.

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.

Telematics and sentinel health information system with general practitioners in Aquitaine, southwest France

A sentinel health information system using a telematics system to collect epidemiological data from a network of general practitioners (GPs) making up 5% of the GP population was set up in October 1986 in Aquitaine, France. In the first year, four topics were under surveillance. The GPs reported data for each case diagnosed by filling out a questionnaire displayed on their home terminal (Minitel), which transmitted the data by standard telephone lines to a central minicomputer located in the Bordeaux University Medical Centre. Regular feedback was provided to the participating GPs, public health officials and the Bordeaux Medical School. A detailed report of GP participation is presented, the reliability of our findings is discussed in terms of the motivational factors of participants, and the usefulness of the system is evaluated both for immediate teaching implications and for future research possibilities.

Epidemiological surveillance of suicides and attempted suicides in Aquitaine, south-west France, using an original computer network of sentinel general practitioners

To improve the epidemiological study of suicide and attempted suicides in Aquitaine, France, we developed a comprehensive surveillance system based on the input of Sentinel General Practitioners (SGPs). From October 1986 to May 1988, for each case of suicide or attempted suicide, the SGPs reported epidemiological data to our system through a computer network of personal home terminals (Minitels). Data included age, sex, method and result of attempt and antecedents. In an analysis of the relationship between the suicidal method, antecedents and results of suicidal act, the principal findings were a high rate of antecedents of suicide attempts by drug overdoses, hangings and drownings; and no antecedents for attempts by the use of firearms. This may show that the increasing accessibility of firearms is making it more likely that impulsive suicide attempts will be lethal.

[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.

[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.

Prevalence of legionellosis among adults: a study of community-acquired pneumonia in France

Over a 24-month period, 274 patients with community-acquired pneumonia were hospitalized in Departments of Medicine at hospitals in Bordeaux, Lyon, Marseille, and Toulouse. Etiology of the pneumonia was determined either by organism identification or by indirect immunofluorescence in only 139 cases (51%). The most frequently isolated etiological agents were Streptococcus pneumoniae (34 cases), Legionella pneumophila (29 cases) and Mycoplasma pneumoniae (24 cases). The majority of patients with legionellosis were male (79%), middle aged (mean age: 53 years), and living in urban areas (69%). Their clinical features were atypical and did not differ from those of other pneumonias. Four patients with legionellosis (13.8%) died. L. pneumophila was isolated directly in only three instances. The study confirms the high prevalence of legionellosis (20%) among pneumonias of identified etiology. The fact that these cases had an atypical clinical presentation and that isolation of the organism was difficult reinforce the need to apply the CDC criteria for the interpretation of positive serological titers.

Constrained poststratification

Adjustment for covariates (or poststratification) is frequently used in the analysis of randomized clinical trials. The purpose of such analysis is mainly to eliminate some residual bias resulting from any imbalance between treatment groups for some important covariates. Usually, covariate effect is modeled with the data at hand. In this paper, we present a new method of poststratification ("constrained poststratification") which consists of estimating the prognostic significance of covariates in a large historical data base, transferring the model's coefficients into the (smaller) randomized trial data set, and estimating treatment effects conditional on this a priori information. In a simulated experiment, constrained poststratification allowed not only reduction of the bias but also enhancement of the efficiency of the estimation of treatment effect.

Risk of preangioplasty occlusion and myocardial infarction in one-vessel-disease patients scheduled for percutaneous transluminal coronary angioplasty

Coronary occlusion or myocardial infarction occurred in 50 of 394 (13%) one-vessel-disease patients awaiting percutaneous transluminal coronary angioplasty (PTCA). To identify risk factors for these events, we first matched the 37 patients who demonstrated occlusion on the immediate preangioplasty repeat angiogram with 37 patients who did not. Matching was based on the time interval between angiograms, the date of the procedure, and the site of the lesion. Preangioplasty occlusion patients did differ from controls by age (47 +/- 11 vs 54 +/- 8 years, P less than .01), smoking status (34/37 vs 24/37, P less than .01), and angina class (2.6 +/- 1.0 vs 2.3 +/- 0.7, P less than .10) at the time of the first angiogram. Second, we pooled the data of the 37 preangioplasty occlusion patients with those of the 13 patients with preangioplasty myocardial infarction. The 50 cases with complication (coronary occlusion or myocardial infarction) were younger (47 +/- 12 vs 54 +/- 8 years, P less than .01), more often smokers (42/50 vs 24/37, P less than .05), and more symptomatic (2.7 +/- 0.8 vs 2.3 +/- 0.7, P less than .05) than the 37 controls. This study suggests that young smokers with severe angina are at high risk of preangioplasty occlusion and/or myocardial infarction; prompt management of these patients, when considered for PTCA, seems advisable.

[Measuring severity in trauma resuscitation]

ISS is the most widely used anatomic trauma severity index. This scale uses clinical judgement. It is therefore a subjective method, the validity of which is somewhat questionable. The aim of this study was to compare the clinical index ISS with a new non-specific score; the "simplified acute physiology score" (SAPS). Five-hundred trauma patients were checked retrospectively. Were excluded small traumas which did not require ICU hospitalization. ISS were all calculated by the same specialist and SAPS was drawn out of the initial blood sample examination. The sensitivity (proportion of true positive) and the specificity (proportion of true negative) were calculated for the two scores at all different cut-off points. "Receiver operating characteristic curves" (ROC) were drawn and their areas were compared by means of the Hanley test. The best Youden index, i.e. the fewest false positives for the most true positives, was also calculated. Mean ISS was 23.3 +/- 9.2. Youden index was 0.1; sensitivity and specificity were respectively 57 and 52% for the cut-off points. Mean SAPS was 8.7 +/- 4.3. Youden index was 0.3 and sensitivity and specificity were respectively 68 and 62%. ROC curve area for SAPS was 0.69 +/- 0.02. ROC curve area for ISS was 0.56 +/- 0.03 (p = 0.0001). In trauma, SAPS seemed to be a better predictor of outcome than ISS.

[Has prenatal ultrasonic diagnosis modified the prognosis of intestinal atresia? Results of a multicenter study]

A multicentric investigation concerning intestinal atresia diagnosed in french university hospitals from 1979 to 1983, has been done. Out of 96 exploitable cases coming from 8 centers, 28 correspond to intestinal atresias which had subject to prenatal echographic diagnosis: that is 29%. 15 of the 96 atresias were affected with trisomy. 21 which had not been recognised in utero. Concerning the isolated duodenal atresia, not accompanied by any other malformation, the post surgical evolution has been appreciated during the 12 months following the surgical operation. There was no statistically significant difference, in favour of the group of children whose malformation has been recognised in utero, concerning the number of post surgical complications. This result, apparently deceitful, can be explained by the early management of these malformations in specialised centers which have participated in this study.

Prognosis in juvenile dermatopolymyositis: a cooperative retrospective study of 70 cases

A retrospective multicenter study was conducted with 70 patients with juvenile dermatopolymyositis. Among survivors with sufficient follow-up (at least two years), a good prognosis subgroup was characterized by significantly better (P less than 0.001) initial response to steroids and less frequent pharyngeal involvement when compared to other patients in a poor prognosis subgroup with significant sequelae or still active disease. Patients who died had more severe pharyngeal involvement than those who survived (P less than 0.05).

A statistical method for the estimation of neuronal response latency and its functional interpretation

The functional role of many central nervous structures has been inferred from the temporal relationship of a neuronal response with the different sensory and motor events in an experimental design such as when an animal performs a trained movement in response to a conditioned stimulus. However, this kind of data analysis leads to problems in estimating the occurrence and latency of any neuronal response. We examine these problems and propose a novel technique of data analysis to estimate the point of change in a sequence of neuronal discharge. Furthermore, data can be tested to see whether the neuronal response is related to the conditioned stimulus or the motor act. The method can also be used in the simple situation of determining the latency of a neuronal response after a stimulus.

Deconvolution analysis of radionuclide angiocardiography curves: problems arising from fragmented bolus injections

Deconvolution analysis of radionuclide angiocardiography time-activity curves (TAC) in the cases of fragmented bolus injections was studied by using a new deconvolution technique based on the maximum a posteriori estimator. This method was first tested by simulation studies which showed its capability for accurate handling of deconvolution both for single and double peak input functions. These simulations have proved this technique to have advantages over a Fourier transform division method used with a low-pass filter. In patient studies, deconvolution of pulmonary TAC by superior vena caval TAC produced poor results in double peak (fragmented) bolus injections, compared with single peak bolus injections (SPBI). This discrepancy seems to be due to the fact that the postulates of linearity and invariance, on which deconvolution analysis is based, do not hold for the 'cardiopulmonary system' which extends from the superior vena cava to the lung. The differences between the model and the real system appear unimportant for SPBI. However, differences become apparent for fragmented bolus injections. Deconvolution analysis should be avoided with this type of input function in this cardiopulmonary system.

[Prevalence of migraine in a working population group in the Aquitaine region. Methodology and results (author's transl)]

To our knowledge, no study of prevalence of migraine has ever been carried out in France. Since this is a well defined disease with precise diagnosis and therapy, it was possible for us to carry out a survey on a large population. We therefore had to build an automatic process if migraine diagnosis using simple computerized questionnaires. The results presented are these relative to a survey carried out on a working population group of about 3,000 persons. These were interviewed during the annual medical examination which workers in France have to undergo. The socio-economic consequences of migraine could thus be studied.

[Classical special investigations in hospital neurology. Evaluation of their diagnostic contribution (author's transl)]

A quantitative analysis of the diagnostic contribution of the classical special investigation normally used in hospital neurology. Six examinations were studied: laboratory blood investigations, electroencephalogramm, lumbar puncture, optic fundus, standard skull X-ray, standard spine X-ray. The analysis involved 548 patients in whom 2219 examinations were performed with a yield of 26 "corrected" diagnosis (a diagnosis in which there was a clinical error corrected in the light of the results of these examinations).