Amount Of Slow Activity Research Articles

A Review of the Usefulness of the Standard EEG in Psychiatry

The goal of this paper is to draw conclusions about the usefulness of the standard EEG in psychiatry. In general, two thirds of psychiatric referrals for an EEG are expected to provide useful information. The emphasis in schizophrenia is placed on left-sided abnormalities, especially on the left temporal area. In mood disorders the emphasis is on right-sided foci, in addition to the controversial 6/sec spike and wave complexes, small sharp spikes and positive spikes. In the acute stage of alcoholism, a relationship is seen between the degree of intoxication and the amount of slow activity, while in the chronic stage an increase in slow activity is seen, but another change is fast activity on the temporal areas. During withdrawal a low seizure threshold can be seen as irregular bilateral spike and wave complexes. During abstinence 2-4 yr may be required before slow wave sleep is normal in all regards. Among the organic mental syndromes, delirium shows slow activity, except in delirium tremens, which often is associated with a normal record with fast activity. In dementia the prevalence of EEG abnormalities is related to the degree of impairment. After five sessions of ECT diffuse slow waves are often seen. In other conditions, among developmental disorders about one half of autistic children show abnormalities and epileptiform activity is not uncommon. Mild nonspecific abnormalities are seen in about 40% of dyslexics and also in behavior disorders. Anxiety disorders include anorexia nervosa, showing abnormal background activity related to the effect of starvation on cerebral metabolism. In panic attacks paroxysmal activity can be seen. In borderline personality positive spikes have been (again) associated with impulsivity and 6/sec spike and wave complexes with interpersonal problems. Of the drugs of abuse psilocybin and phencyclidine are often associated with generalized epileptiform patterns and with marijuana the alpha shows a decreased frequency with increased amplitude. Typically, an increase in slow activity is seen with psychotropic drugs if there is a change in the level of awareness. Finally, distinctive personality traits are, at times, seen in temporal lobe epilepsy and the phenomenon of "forced normalization" may appear when seizures stop and psychotic symptoms appear.

Aging and spectral analysis of EEG in normal subjects: a link to memory and CSF AChE.

We studied the effect of aging on EEG spectra recorded from T5-O1 (T6-O2) derivation. The aging series composed of 52 normal individuals aged 20 to 91 years. Seventy-nine per cent of visual and 81% of quantitative EEGs were considered normal. The absolute amplitude of delta and theta bands and absolute power of delta band were lower for the oldest group (aged 60 and over) than for the youngest group (aged 20-39 years). Age was inversely related to the amount of delta and theta indicating that the amount of slow activity in quantitative EEG does not increase with age in the context of good health status. Women had more beta activity compared with men. In addition, the amount of beta and alpha bands showed tendency for a reduction with age. Fifteen subjects aged 50 years or older participated in a 2-year follow-up including EEG and neuropsychological evaluation. Seven of them deteriorated in learning ability and showed increase in delta activity. In the oldest age group, delta amplitude was positively correlated with intrusion errors in the list learning test and inversely related to acetylcholinesterase activity of the CSF. Thus, a link between the cholinergic system, EEG slowing and memory problems in old age is suggested.

Effects of the Removal of Phenytoin, Carbamazepine, and Valproate on the Electroencephalogram

We report the EEG changes that occurred on discontinuance of phenytoin (PHT), carbamazepine (CBZ), and valproate (VPA) in patients with active epilepsy. Discontinuation of CBZ was associated with an increase in mean frequency of dominant rhythm and reduction in amount of slow activity. Patients who had a marked increase in seizures on discontinuation of an antiepileptic drug had a slower mean dominant rhythm at baseline than did patients who did not have an increase in seizures. Subsequent EEGs, during and at the end of drug reduction, showed an increase in bursts of interictal epileptiform activity (IEA) and in slow activity in patients who had a marked increase in seizures. The amount of slow activity and IEA did not alter in patients who did not have an increase in seizures. No patients developed photosensitivity.

Electroencephalographic Studies: Slow Activity During Hyperventilation in Relation to Age

There is a definite relationship between the age and the amount of slow activity during hyperventilation in epileptic and non-epileptic patients. An analogous relationship to age was found for the spontaneous delta activity of patients with idiopathic epilepsy.