Slow-wave activity in the spectral analysis of the electroencephalogram is associated with cortical dysfunctions in patients with Alzheimer's disease

Cortical functions and slow-wave activity in the spectral analysis of the electroencephalogram (EEG) have been studied in 19 patients with Alzheimer's disease (AD), 18 patients with Parkinson's disease with dementia (PD), and 14 control subjects (C) to determine which functions are explained by their relationship of slow-wave activity. Multiple regression analyses revealed that a variance in visual functions, praxia of the hand, automatic speech, speech understanding, and retrieval from semantic memory were explained by their relationship with slow-wave activity in EEG in the AD group but not in the PD or C groups. The PD and AD groups exhibited equal cortical dysfunctions and mean amplitudes of delta activity in EEG. The cholinergic system, disrupted in AD, has been shown to be important in the regulation of neocortical electrical activity and may be associated with the processing of cortical functions.

Randomized controlled pilot study of vigabatrin versus carbamazepine monotherapy in newly diagnosed patients with epilepsy: an interim report

At present, 34 patients aged 15 to 63 years with newly diagnosed epilepsy have been randomly assigned to vigabatrin (n = 17) or carbamazepine (n = 17). Evaluation of clinical data, neuropsychological assessment, quantitative spectral electroencephalogram (EEG), and somatosensory- and visual-evoked potentials at baseline and after a 3 months' maintenance phase are presented for 12 patients on vigabatrin and for 11 patients on carbamazepine. Among these patients, retention rate in the maintenance phase of the study is 75% for vigabatrin patients (two noncompliant patients and one nonresponder dropped out) followed up for a mean of 11 months (range, 5 to 16 months). The retention rate for carbamazepine is 100% for the 11 patients, followed up for a mean of 9 months (range, 3 to 17 months). Patients receiving vigabatrin showed significant improvements in sustained concentration and tasks requiring flexible mental processing after the 3-month maintenance period, compared to baseline. In the carbamazepine group, there was improvement only in delayed list recall, and in contrast, errors in visuomotor tasks requiring processing increased significantly. Patients on carbamazepine demonstrated slowed occipital mean frequencies, but vigabatrin treatment was not associated with any significant quantitative EEG changes. Significant prolongation of somatosensory-evoked potential N19 latencies was seen with both carbamazepine and vigabatrin.

The effect of gamma-vinyl-GABA on the performance of nucleus basalis-lesioned rats in spatial navigation task

The present study investigates whether the stimulation of gamma-aminobutyric acid (GABA)ergic system affects spatial navigation deficits induced by the lesioning of the nucleus basalis (NB). Thus, the effect of gamma-vinyl-GABA treatment which elevates the GABA levels in brain was studied on water maze task both in unoperated and NB-lesioned (ibotenic acid) rats. The subchronic administration of gamma-vinyl-GABA aggravated dose-dependently NB lesion-induced deficits, although it did not impair the performance of unoperated rats in this task. The imbalance between GABAergic system and cholinergic or non-cholinergic systems of the NB may contribute to spatial navigation deficits in rats.

Neurotransmitter changes in Alzheimer's disease: implications to diagnostics and therapy

Changes in the cholinergic, serotonergic, noradrenergic, dopaminergic, GABAergic and somatostatinergic neurons were investigated to determine their roles in Alzheimer's disease (AD). Markers for these systems were analyzed in postmortem brain samples from 20 patients with AD and 14 controls. In the CSF study, markers for the cholinergic neurons (choline esterase, ChE) and for the somatostatinergic neurons (somatostatin-like immunoreactivity, SLI) were assayed for 93 and 75 probable AD patients and 29 and 19 controls, respectively. Activity of choline acetyltransferase (CAT) was decreased by 50-85% in four cortical areas and hippocampus in patients with AD, but not in other areas of the brain, indicating a profound deficit in the function of cholinergic projections ascending from the nucleus basalis to the cerebral cortex and hippocampus in AD. Muscarinic receptor binding was reduced by 18% in the frontal cortex but not in other areas of the brain in AD. Serotonin (5HT) concentrations were reduced (by 21-37%) in hippocampal cortex, hippocampus and striatum; and 5HT metabolite levels were lowered (by 39-54%) in three cortical areas, thalamus and putamen in AD patients. Concentrations of noradrenaline (NA) were reduced (18-36%) in frontal and temporal cortex and putamen. These data imply that serotonergic and noradrenergic projections are also affected in AD but less than the cholinergic neurons. Dopamine (DA) concentrations in AD patients were reduced by 18-27% in temporal and hippocampal cortex and hippocampus, while HVA, the metabolite of DA, was unaltered. Glutamic acid decarboxylase activity was not altered in AD. SLI was decreased (28-42%) in frontal, temporal and parietal cortex, but not in thalamus and putamen in patients with AD. Frontal tangle scores correlated most strongly with cortical CAT activity reduction and less so with decreases of 5HT, NA and DA, indicating a closer correlation with the cholinergic changes and severity of AD than with other neurotransmitter deficiencies. ChE activity and SLI were reduced by 20% and 35%, respectively, in CSF of the whole group of AD patients as compared to the controls. Comparison of CSF findings between four subgroups of dementia severity indicated that the SLI was already reduced in the group of mildest AD (-31%), while ChE activity was not. Although ChE activity in CSF declined in relation to dementia severity, however, the maximal reduction was only modest (-30%). On the other hand, SLI in CSF showed only a slight further reduction (up to -41%) as the dementia become more severe.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration of vigabatrin (gamma-vinyl-gamma-aminobutyric acid) affects the levels of both inhibitory and excitatory amino acids in rat cerebrospinal fluid

The effect of vigabatrin (gamma-vinyl-gamma-aminobutyric acid), a new anticonvulsant drug, on the transmitter amino acids in rat cisternal CSF was studied. CSF was collected through a permanently implanted polyethylene cannula from freely moving rats at 5, 24, 48, and 96 h after administration of 1,000 mg/kg of vigabatrin. The free gamma-aminobutyric acid (GABA) level was elevated maximally (13.5-fold; p less than 0.01) at 24 h after injection. The homocarnosine (GABA-histidine) level also was increased (123%; p less than 0.01) at 24 h after injection, and its concentration remained at the same level for the next 3 days. Glycine and taurine concentrations had increased [31% (p less than 0.05) and 63% (p less than 0.01), respectively] at 5 h after injection. It is interesting that the levels of glutamate and aspartate increased [330% (p less than 0.05) and 421% (p less than 0.01), respectively] at 96 h after injection, the time when the free GABA level had returned to the baseline concentration and the vigabatrin level was 3% of the maximal concentration. The present study indicates that a single dose of vigabatrin in rats elevates levels of both the inhibitory and excitatory amino acids in CSF. However, the temporal profile of observed changes in relation to vigabatrin injection shows that neither the long-lasting elevation of GABA content nor the increase in glutamate and aspartate levels correlates with the level of vigabatrin in CSF. These findings suggest that the excitatory mechanisms are also augmented following acute administration of vigabatrin, especially when the content of GABA had decreased to the baseline level and the level of vigabatrin was low.

Somatostatin-like immunoreactivity in the CSF of patients with dementia associated with alcoholism

Cerebrospinal fluid somatostatin-like immunoreactivity (CSF SLI) was determined for 9 patients with chronic alcohol ingestion and dementia associated with alcoholism and for 8 age-equivalent controls. The CSF SLI was significantly reduced (32%) in the alcoholics with dementia as compared to the controls. This finding is in accordance with previous observations on the relationship between reduced CSF SLI and cognitive impairment in various neuropsychiatric disorders, and extends this finding to patients with dementia associated with alcoholism.

Somatostatin and epilepsy

Hippocampal neurons containing somatostatin have been shown to be vulnerable in some experimental models of epilepsy. In this report, we describe our recent findings about the seizure-related changes in somatostatin in brain tissue and cerebrospinal fluid (CSF) in experimental and human epilepsy. These data strengthen the view that the somatostatinergic system is affected in epilepsy.

Decreased somatostatin-like immunoreactivity in the cerebrospinal fluid of chronic schizophrenic patients with cognitive impairment

The level of cerebrospinal fluid somatostatin-like immunoreactivity (CSF SLI) was determined for 11 chronic schizophrenic patients with moderate cognitive impairment and for 8 controls. The CSF SLI was significantly reduced (37%) in schizophrenic patients, but this decrease did not correlate with the degree of cognitive decline measured by the Mini-Mental State Examination, with psychotic symptoms estimated by the Brief Psychiatric Rating Scale, or with the neuroleptic dose. Although a reducing effect of long-term neuroleptic treatment cannot be totally excluded, the present study suggests that the CSF SLI level is decreased in cognitively impaired schizophrenic patients, as in many other disorders with cognitive impairment.

Cerebrospinal fluid somatostatin in delirium. II. Changes at the acute stage and at one year follow-up

Cerebrospinal fluid somatostatin-like immunoreactivity (CSF SLI) was determined for elderly delirious patients during the acute stage and after one-year follow-up. The SLI levels were compared with age-equivalent controls. For the group as a whole, and also when the group was subdivided according to the severity of cognitive decline at the acute stage, type of delirium, or the central nervous system disease, delirious patients showed significant reduction of SLI as compared with the controls. In the follow-up, we observed a further reduction of CSF SLI together with significant correlations in the second and third samples between SLI levels and Mini-Mental State Examination score. Our results suggest a role for somatostatinergic dysfunction in the genesis of some symptoms of delirium. This dysfunction may be a common phenomenon in various forms of delirium and dementia.

Autonomic nervous system function in Baltic myoclonus epilepsy

Baltic myoclonus epilepsy (BME) is a neurodegenerative disease characterized by tonic-clonic seizures, myoclonus and a progressive course. The aim of the present study was to assess the clinical symptoms and signs of possible involvement of the autonomic nervous system (ANS) and objectively evaluate autonomically mediated cardiovascular reflexes in this syndrome. Fifteen patients with BME and 14 healthy control subjects were studied. Thirteen (87%) of the patients had symptoms suggesting ANS dysfunction. The most common symptoms were postural dizziness and sweating disturbances. The heart rate variation during deep breathing was lower in patients than in controls. The heart rate response and systolic blood pressure response during tilting were similar in both groups. Our results suggest a mild parasympathetic hypofunction and an intact sympathetic function in ambulatory patients with BME.

Therapeutic intervention in mentally retarded adult epileptics

Clinical features of epilepsy, especially those connected with drug therapy, were evaluated for mentally retarded adult epileptics who were admitted to the neurological out-patient unit during 1977-83. These features were re-evaluated in 1985 and compared with findings from the first visit. During follow-up, the type and frequency of seizures were determined and if possible, medical therapy was either concluded or changed. The therapeutic intervention resulted in the use of fewer and less toxic drugs, for which the serum concentrations were more often within recommended ranges. These aspects may be due to the significant decrease in seizure frequency observed. In order to provide patients with the most efficacious therapy, the therapeutic needs of mentally retarded adult epileptics should be evaluated by a neurologist familiar with epilepsy.

Epileptic attack, delirium, and a Creutzfeldt-Jakob-like syndrome during mianserin treatment

Our report concerns 2 patients who developed delirium after an epileptic attack during mianserin treatment. In both cases the EEG showed a change with periodic sharp slow complexes similar to that seen in Creutzfeldt-Jakob disease. The symptoms subsided, however, and the EEG normalized after the antidepressant was discontinued, suggesting a noxious response to mianserin. If Creutzfeldt-Jakob-like changes in the EEG occur, the possible effect of antidepressant medication should be considered.

Brain amines and neocortical EEG in young and aged rats

1. Frontal and parieto-occipital electroencephalography (EEG) of young (4 months-old) and aged (17 and 22 months-old) Wistar rats were analyzed, both during movement and during waking immobility. 2. The levels of monoamines, serotonin and their metabolites were measured from the frontal cortex, parieto-occipital cortex, hippocampus, brainstem and midbrain. 3. In aged rats, as compared to young rats, the most apparent changes of the quantitative EEG spectrum were the decreased amplitude of alpha (5-10 Hz) and beta (10-20 Hz) frequency bands in the frontal and parieto-occipital cortices during both movement and waking immobility behavior (p less than 0.05). 4. The levels of dopamine (DA), homovanillinic acid (HVA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) or the ratios of 5-HT/5-HIAA and DA/HVA did not differ between young and aged rats in any brain region studied, with the exceptions of brainstem DA and parieto-occipital 5-HIAA, which were elevated in aged rats (p less than 0.05). 5. In the frontal cortex, hippocampus and midbrain, noradrenaline (NA) levels of aged rats were slightly increased as compared to young rats (p less than 0.05). 6. NA levels of the parieto-occipital cortex and brainstem did not change during aging. 7. Furthermore, there were no clear correlations between the decreased amplitude of the quantitative EEG spectrum and monoamine or serotonin concentrations, or the ratios of 5-HT/5-HIAA and DA/HVA in the cerebral cortex of aging Wistar rat.(ABSTRACT TRUNCATED AT 250 WORDS)

2',3'-cyclic nucleotide-3'-phosphodiesterase activity as an index of myelin in the post-mortem brains of patients with Alzheimer's disease

The activity of 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) was determined as an index of myelin in the post-mortem brain samples of 16 patients with Alzheimer's disease (AD) and of 14 controls. The CNPase activity was mildly increased in the temporal, hippocampal and parietal cortex in AD subjects pointing to a relative sparing of myelin as compared to the neuron loss within cortex in AD. In the hippocampus the CNPase activity was decreased in AD patients indicating loss of myelin and thus myelinated axons in this area in AD.

Somatostatin, neuropeptide Y, GABA and cholinergic enzymes in brain of pentylenetetrazol-kindled rats

We studied the effect of pentylenetetrazol (PTZ)-induced kindling (35 mg/kg, i.p., daily) on somatostatin-like immunoreactivity (SOM) with special attention to the duration of changes (rats were sacrificed either 10 days or 4 months after the development of kindling) and to transmitters or modulators related to somatostatin (neuropeptide Y (NPY), GABA, choline acetyltransferase (ChAT), acetylcholinesterase (AchE]. In rats sacrificed 10 days after the last kindled seizure, SOM was elevated in frontal cortex and striatum (p less than 0.01); NPY was elevated in frontal cortex, striatum and hippocampus (p less than 0.05) of kindled or prekindled rats (i.e., rats which were treated daily with PTZ but did not express three consecutive generalized seizures). ChAT activity was slightly decreased (p less than 0.05) in cortex. GABA levels and AchE activity were unchanged in kindled cortex. In rats sacrificed 4 months after the development of kindling none of the parameters analyzed differed from controls. The present study suggests that the cortical and striatal neurons containing SOM/NPY are affected by PTZ-kindling. The cortical cholinergic system is affected to a much smaller extent. The neuropeptide changes are not persistent, as is the lowered seizure threshold, so they are probably not involved in the maintainance of the latter.

Specificity of vigabatrin for the GABAergic system in human epilepsy

The therapeutic action of vigabatrin (gamma vinyl GABA, GVG) has been reported to be mediated by GABAergic neurotransmission. In the present study, we evaluated different neurotransmitter systems in the cerebrospinal fluid (CSF) of patients with complex partial epilepsy, before and during GVG treatment. The markers of the GABAergic system (free GABA, total GABA, homocarnosine) showed a two- to threefold elevation. There was also an increase in glycine during the 6 months of GVG treatment. In contrast, we did not find any constant CSF changes in either excitatory amino acids or in markers of the cholinergic (acetylcholinesterase), dopaminergic (homovanillic acid), serotonergic (5-hydroxyindoleacetic acid), or peptidergic (somatostatin, prolactin, beta-endorphin) systems. This finding (except an elevation in glycine) was in agreement with previous studies which suggest a specific action of GVG on the GABAergic system. The role of glycine in antiepileptic efficacy of GVG needs further evaluation.

EEG spectral analysis in delirium

Spectral analysis of EEG was conducted for 51 elderly delirious patients meeting the Diagnostic and Statistical Manual of Mental Disorders III (DSM-III) criteria and for 19 controls. As a whole group, and also when subdivided according to the type of delirium, severity of cognitive decline or the type of central nervous system disease, delirious patients showed significant reductions of alpha percentage, increased theta and delta activity and slowing of the peak and mean frequencies and these changes were also obvious in individual recordings. The alpha percentage and various ratio parameters correlated significantly with Mini Mental State score, and delta percentage and mean frequency with the lengths of delirium and hospitalisation. The results indicate an association between spectral EEG changes and severity of cognitive deterioration in delirium.

Cerebrospinal fluid somatostatin in delirium

Cerebrospinal fluid somatostatin-like immunoreactivity (CSF SLI) was determined for 67 elderly patients who met the DSM-III criteria for delirium and for 19 age-matched controls. As a group, and also when subdivided according to the type of delirium, severity of cognitive decline or the type of central nervous system disease, the delirious patients showed significant reductions of SLI compared with the controls, together with a declining trend associated with increasing cognitive dysfunction. These findings are in accordance with previous observations that reduced CSF SLI is associated with diseases in which cognitive function is disturbed and they extend this finding to delirium.

Effect of cysteamine on somatostatin-like immunoreactivity in the amygdala-kindled rat brain

Previous studies have shown that a somatostatin-depleting drug, cysteamine (CYS), suppresses kindled seizures. However, no data is available concerning the levels of somatostatin-like immunoreactivity (SLI) in the kindled rat brain after CYS administration. In the present study, we used radioimmunoassay to measure SLI in the frontal cortex, amygdala + piriform cortex, hippocampus, striatum and hypothalamus: 1) in control rats, 2) in amygdala-kindled rats decapitated 14 days after the last stimulus, and 3) in amygdala-kindled rats decapitated 14 days after the last stimulus but treated either 11 days or 4) 4 hours before decapitation with CYS (100 mg/kg, subcutaneously). The results showed that, compared to controls, in kindled rats SLI was elevated both in the ipsi lateral (28%, p = 0.0372) and contralateral (17%, p = 0.0078) frontal cortex. Compared to kindled rats, CYS given 4 hours before decapitation decreased SLI in the frontal cortex (to 71%, p = 0.0066) and hippocampus (to 72%, p = 0.0027), but compared to the controls, only in the hippocampus. In rats given CYS 11 days before decapitation, SLI did not differ from either the controls or from the kindled rats. In conclusion, the somatostatinergic system is affected in amygdala-kindling; but the relationship of anatomical localization and the magnitude of CYS-induced decrease of SLI to elevated seizure threshold needs to be studied further.

Incidence and prevalence of epilepsy in adults in eastern Finland

In Finland, only limited data exist on the epidemiology of epilepsy in adults. This prompted us to study the incidence and prevalence of epilepsy in a population over 15 years of age, residing in Eastern Finland. In a retrospective study, various medical data sources were used to identify and reexamine all patients with established or suspected epileptic seizures during 1960-1979. A total of 1,233 patients with active epilepsy were identified. Mean annual incidence of epilepsy was 24/100,000. Age-specific incidence ratios tended to increase with advancing age. Prevalence of active epilepsy was 629/100,000. Both prevalence and incidence were higher in males than in females. Age-specific prevalence of active epilepsy increased until 40-50 years of age, and declined in the oldest age groups. Of the various seizure types, highest prevalence ratios were observed for partial secondarily generalized seizures, complex partial seizures, and tonic-clonic seizures. Prevalence of partial seizures and generalized seizures had a different age-related pattern.

Effect of cysteamine on levels of somatostatin-like immunoreactivity and catecholamines and on electroencephalogram in the rat brain

Cysteamine (CYS) is known to be a quite specific depletor of somatostatin in the rat brain. In the present study we investigated the effect of CYS (100 mg/kg, 300 mg/kg, subcutaneously) on levels of somatostatin-like immunoreactivity (SLI) in the brain and cerebrospinal fluid, on catecholamines in the cortex, and on spectral cortical electroencephalogram (EEG) of rat. SLI was decreased in both the cortex and the striatum (p less than 0.05) of CYS-treated rats, but no change was seen in SLI of CSF. Cortical levels of dopamine, noradrenaline and homovanillic acid were decreased (p less than 0.05) following administration of either dose of CYS. In EEG, during mobility both the frontal and occipital peak (Fp) and mean (Fm) frequencies were slowed (p less than 0.05). Frontally, the amplitude of the frequency bands 1.5-3Hz and 3-5Hz was increased (p less than 0.05). During immobility the Fp and Fm were also slowed. In frequency bands of 3-5Hz, 5-10Hz and 10-20Hz the amplitude was decreased (p less than 0.05), indicating that, in addition to theta frequency, the low voltage fast activity is also affected by CYS. According to our results, both the cortical intrinsic neurons containing somatostatin and also the ascending catecholaminergic systems are affected after the single administration of CYS concomittantly with, but not necessarily related to, changes in different frequency bands in EEG.

Cross-cultural studies of dementia. A comparison of mini-mental state examination performance in Finland and China

The Mini-Mental State Examination of Folstein et al was translated into and culturally adapted to Chinese and Finnish and used in dementia surveys involving probability samples of 2187 Shanghai elderly, aged 65 to 74 years, and 525 Finns of the same age group. The mean scores of these two groups were statistically different owing to the lower scores of Shanghai subjects who had no formal education. When this subset of 579 subjects was eliminated from the analysis, the distribution of total scores was almost identical in the two populations, suggesting that the Mini-Mental State Examination can be used in disease populations, provided education is taken into account. However, there remained cultural differences in regard to individual test items; the Chinese had better recall but did not do as well as Finnish or US subjects when asked to copy a figure.

Delirium among elderly persons admitted to a psychiatric hospital: clinical course during the acute stage and one-year follow-up

Seventy elderly patients meeting the DSM-III criteria for delirium were examined during the acute stage and followed up to one year. The mean age of the patients was 75 years (range 60-88), their delirium lasted on average 20 days (range 3-81) and the psychiatric hospitalization on average 30 days (range 8-365). The most common etiologies for delirium were stroke, infections and metabolic disorders. For 57 cases (81%) a predisposing structural brain disease was found. During the index admission, the cognitive dysfunction associated with delirium ameliorated significantly (the mean +/- SD Mini-Mental State Examination score 9.7 +/- 6.6 at admission and 13.9 +/- 7.2 at discharge; P less than 0.001), but during the one-year follow-up progression of the basic central nervous system disease was seen together with declining cognition and deterioration of functions of daily living.