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Ageing is known to be accelerated by risk-factors. The continuity between normal and pathological ageing is still quite disputed. Concerning cerebral ageing, the use of statistical methods on electroencephalographic (EEG) parameters appeared to be interesting. In this study, three different groups of elderly subjects were examined by EEG: normal subjects without neurological nor cardiac disease, subjects with Alzheimer-dementia (AD) and cardiac patients without cerebral clinical signs. Stepwise discriminant analysis showed that EEG-parameters discriminating normal subjects from cardiac patients were different from those discriminating AD-patients from normal. Furthermore, AD-patients could be well-discriminated from elderly cardiac patients.

It is a widely accepted that normal ageing hardly modifies basal rythms: alpha frequency remains occipital, symmetrical, and reactive when eyes are opened. There is probably a frequency decrease, but this is hard to determine individually in the absence of longitudinal studies. In any event, alpha frequency never drops below 9 cycles per second until after 80 years of age. Localized and mostly left-sided temporal abnormalities in normal subjects have been noted several times in the literature. However, these pose the problem of early detection of brain damage in patients with hypertension, heart of pulmonary disease. Therefore, further EEG studies on normal and pathological cerebral ageing should investigate clinically well-defined populations.

Analysis of EEG background activity in epilepsy has been much less used than automatic detection of paroxysmal figures. However, it would be useful to study the background activity with precision. The techniques used can belong to the time domain or the frequency domain. They make it possible to study the variations of EEG background activity as a function of the drug therapy and the type of epilepsy; some prognostic indices can then be derived for different kinds of epilepsy. It seems probable that topographic displays of background frequency bands will be very interesting in the near future. Finally, automatic analysis of sleep recordings in epileptic patients also makes it possible to test drug effects and modifications of sleep stages, as a function of the type of epilepsy.

The electrophysiological diagnosis of peripheral neuropathy in diabetics becomes increasingly difficult with the increase in number of parameters measured. We have examined 102 subjects: 60 diabetics, 32 control subjects and 10 with impaired glucose tolerance. From the 37 recorded parameters during 8 examinations, a linear discriminant analysis allowed us to separate the 19 diabetics with clinical neuropathy and the control subjects with only 5 parameters, with a good concordance (96%): the motor conduction velocities (MCV) of the peroneal and median nerves, the amplitude of the action potential (AP) of the sural nerve, the Hmax/Mmax ratio and the M latency of the Hoffman reflex. These parameters, weighted with a coefficient, constitute a score of discrimination. This score has been tested by the Jackknife method on the same sample (94% of well-classified patients), then validated on the other patients. Thus we propose a method to aid the diagnosis of diabetic peripheral neuropathy, without the arbitrary character of the classical single parameter method, and allowing easy repetition.

The medicinal treatments of 639 patients aged over 65 were recorded on admission to hospital. The mean number of drugs consumed was 4.4 +/- 2.8 per patient. Drug interaction was found in 37 p. 100 of the patients on the basis of data published in the Vidal dictionary. The prevalence of interactions increased with the number of drugs prescribed. The medicinal families most frequently involved were digitalis derivatives, antiarrythmic agents, diuretics, anticoagulants and psychotropic drugs. Thirty patients (4.7 p. 100) presented with a side-effect that was directly ascribable to an interaction. Among the iatrogenic adverse reactions 11 were life-threatening, including 8 cases of severe dysrhythmia and 3 cases of gastrointestinal haemorrhages. Altogether, one-third of all iatrogenic disorders were consecutive to a drug interaction. Simple precautions would have considerably reduced the frequency of such side-effects.