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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P300 is a late component of evoked potential which meet special relevance to the study of cognitive processes. P300 indexes categorization processes and the context updating of memory. Its latency reflects the stimulus evaluation time, and P300 amplitude is related to some psychological variables such as expectancy, attention and stimulus significance. In this review, clinical correlation between P300 components and mental diseases are reported, especially dementia, schizophrenia and depression. Delayed P300 latency has been found in Alzheimer disease and in other forms of dementia. Reduced P300 amplitude as well as altered topography has been reported in schizophrenia. In depression, reduced P300 amplitude has been related with longer reaction time. Unfortunately, the diagnosis utility of P300 seems limited. The authors also propose an overview of the actual knowledge on neurobiological findings in the generation of the P300 wave. Anatomical data point out the importance of the limbic system, more specifically, of the hippocampus and the locus coeruleus, in generating and modulating P300 wave. Data from the literature on the psychopharmacological modifications induced by cholinergic, catecholaminergic and other agents, are reviewed. Although the dopaminergic and noradrenergic systems are of some importance, these data emphasise the importance of the cholinergic system for the generation and modulation of P300 amplitude and latency. The value and interpretation of these neurobiological and clinical findings are discussed.
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PMID:[P 300 slow potential. Clinical interest in 3 mental diseases and neurobiology: a review]. 129 92

We studied latent (mild) pulmonary encephalopathy in 14 patients with mild chronic respiratory insufficiency due to the sequelae of pulmonary tuberculosis. All of the patients were between 49 and 62 (mean age: 57.9). None of them had any impairment of daily activities and apparently had a clear consciousness. First, the P300 component evoked by auditory stimuli was examined. Immediately after that, the PO2, PCO2, pH were measured. Then the Hasegawa's dementia scale, the mini-mental state, the "Kanahiroi" test, Zung's depression score, digit span test were also assessed in the 14 patients. P300 components in 7 age-matched normal volunteers were also examined and compared with those in the 14 patients. The mean P300 latency in the patients were significantly prolonged compared with that in the normal volunteers (p less than 0.01). The P300 latency was well correlated with the PCO2, PO2, pH. The results of the "Kanahiroi" test also correlated with these parameters. We suggest that patients with mild respiratory insufficiency due to the sequelae of pulmonary tuberculosis often have latent (mild) pulmonary encephalopathy, and that P300 latency and the "Kanahiroi" test are very useful to detect and evaluate such latent pulmonary encephalopathy.
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PMID:[P300 latency in patients with respiratory insufficiency due to sequelae of pulmonary tuberculosis]. 156 81

Bit-mapped multicomponent CNV complex and reaction time (RT) were recorded and measured in 24 presenile patients with initial symptoms of very mild to moderately severe primary mental deterioration without depression, and in 10 age-matched controls. All patients underwent CT and MRI examinations, EEG spectral analysis and a battery of psychometric test. Significant group differences were obtained for measures of some post-S1 ERP and CNV components, particularly of the post-S1 N1b, P300 and early and late pre-S2 CNV. P300 with increased latency, no significant CNV activity, very prolonged RTs, EEG slowing down and diffuse brain atrophy were observed in the majority of patients with probable presenile Alzheimer's dementia. These results suggest that CNV/RT and EEG activity changes similar to those observed in our patients may constitute a valuable clue for the study of brain dysfunction in the early stage of presenile idiopathic cognitive impairment.
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PMID:Effect of physiological and pathological aging processes on topographic bit-mapped cognitive evoked potentials in presenile subjects. 180 55

The relationship between severity of depression and the P300 latency of auditory event-related potential was investigated in 36 patients with a major depressive episode according to DSM-III. Positive correlations were found between of the P300 latency and the total score of the Bech-Rafaelsen Melancholia Scale (BRMS), the 4 retardation items of the BRMS (motor, verbal, intellectual and emotional) and the item for lowered mood. In contrast, latencies were not associated with the scores of the Hamilton Rating Scale for Depression, which considers retardation to a lesser extent than the BRMS.
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PMID:Latencies of the P300 component of the auditory event-related potential in depression are related to the Bech-Rafaelsen Melancholia Scale but not to the Hamilton Rating Scale for Depression. 188 95

Neuropsychological and psychometric investigations have sometimes attested to and sometimes denied the existence of cognitive perturbations during the early phases of human immunodeficiency virus (HIV) infection (stages II and III of the CDC classification): strictly asymptomatic seropositivity or generalized lymphadenopathy. Therein lies the basis of the debate concerning the neurotropism of the virus and its deleterious effects on the central nervous system (CNS). We hoped to contribute to the resolution of this discussion by recording late evoked auditory potentials, which are composed of two types of components: exogenous responses attesting to the reception of stimuli by specific sensory areas of the CNS, regardless of their informative value for the subject; and endogenous responses that occur later, appearing when the subject is required to distinguish between different stimuli, for example, counting high-pitched sounds randomly distributed among low-pitched ones. The latter responses, which have been most extensively studied for wave P300, are associated with cognitive functions, and alterations of the evoked cognitive potentials have been observed during the course of demential syndromes of various origins. Fifteen individuals were subjected to the protocol for recording long-latency, evoked auditory potentials. These studies were completed by a battery of psychometric tests, two methods for evaluating depression and an assessment of the anxiety level. The results showed a significant lengthening of the latency of wave P300 in the seropositive subjects. This prolongation also affected one of the exogenous components, i.e., wave P2. In addition, their intelligence quotients, regardless of whether the IQ explores the so-called crystallized component or the fluid component of intelligence, were not significantly different from those of the general population.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Cognitive evoked potentials at the stages II and III of human immunodeficiency virus infection]. 192 56

P300 responses to emotive words of different hedonic tones were assessed in depressed patients (unipolar major), patients recovered from the same type of depression and normal controls. Depressed patients showed a smaller amplitude of P300 in response to negatively toned words than to positive words; normal controls showed the opposite pattern and recovered patients showed a pattern of response which resembled that of depressed patients. The experimental trials comparing responses to negative and positive stimuli in relation to neutral words showed significant differences for negative as compared with neutral stimuli, but not for positive as compared with neutral stimuli. Latencies of P300 did not differentiate depressed patients from normal controls. The results are discussed within the context of the 'expectancy' theory of information processing.
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PMID:Perceptual and physiological dysfunction in depression. 232 Jul 2

Ethylene oxide is now frequently used to chemically sterilize heat-sensitive materials in the hospital setting. Previous reports of neurotoxic effects of ethylene oxide have been described in animals and humans. Recent reports suggest that cognitive deficits may be associated with chronic low-level ethylene oxide exposure. We undertook this study of hospital workers with chronic ethylene oxide exposure and compared them with a non-exposed control group in an attempt to detect neurological and neuropsychological abnormalities. Ethylene oxide breathing zone levels of up to 250 ppm in exposed subjects were reported. All evaluations were done without examiners' knowledge of exposure status of the subjects. The exposed group was found to have a statistically significant lower P300 amplitude, bilaterally hypoactive distal deep tendon reflexes and poorer performance on neuropsychological tests involving psychomotor speed. Exposed subjects acknowledged more symptoms and higher levels of depression and anxiety. Nerve conduction velocities and EEG spectral analysis were similar in both exposed and control groups as were scores on most psychological tests. Based upon this information and prior reports, ethylene oxide should be considered in a differential diagnosis of neuropsychological, peripheral and central nervous system dysfunction in workplace settings associated with ethylene oxide exposure.
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PMID:Neurotoxicological evaluation of hospital sterilizer workers exposed to ethylene oxide. 238 Oct 13

In depression studies, it is important to consider healthy subjects with characteristics which may be predictive of depression. Such are anhedonia and some "dysfunctional" attitudes. For this reason, subjects with or without these characteristics were submitted to an experimental paradigm allowing an analysis of their electroencephalographical (CNV and P300) reactivity according to affective value and meaning of stimuli, and according to the probability of occurrence of these stimuli. Subjects were divided into two groups according to their scores on two scales: the Physical Anhedonia Scale of Chapman et al. and the Dysfunctional Attitudes Scale of Weissman and Beck. Several results enabled to differentiate the two groups. Anhedonic and depressogenic subjects were characterized mainly by a particular type of processing for failure situations and for the stimulus which were associated with those situations.
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PMID:[Study of cognitive evoked potentials as a function of the affective value and significance of stimuli in anhedonic healthy subjects with dysfunctional attitudes]. 238 43

The use of biologic markers in the evaluation of borderline personality disorder (BPD) patients is reviewed. Many patients with Axis II BPD have coexisting Axis I diagnoses of which depression is the most commonly reported. Biologic markers have not aided in the diagnosis of BPD, but some markers, particularly EEG sleep, are not only abnormal in BPD, but also appear to discriminate Axis I depression from other Axis I codiagnoses. Monoamine oxidase, in vitro red blood cell lithium ratio, and P300 auditory evoked potential when used alone or in a combined diagnostic approach, show promise in identifying these codiagnoses as well. Dexamethasone suppression and thyrotropin-releasing hormone tests appear nonspecific in this population. Pharmacologic trials have demonstrated that some BPD patients have good therapeutic response to antipsychotics and tranylcypromine and poor response to alprazolam.
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PMID:Biologic markers in borderline personality disorder: a review. 249 95

In elderly patients presenting to an ambulatory practice with complaints of cognitive disturbance, early dementia must be differentiated from depression. The present paper describes the application of standard electroencephalography and evoked potential testing (EEG/EP) and computerized electroencephalography with evoked potential mapping (CEEG/EPM) in the analysis of 64 elderly patients complaining of cognitive disturbance. Although previous reports have claimed a sensitivity level of up to 80% for EEG in demented patients, it appears that a lower sensitivity (37% for EEG alone and 61% for EEG/EP) may be expected at the time of early presentation according to the present study. No EEG/EP abnormalities were detected in patients with depression. In demented patients, CEEG/EPM was abnormal in 85% (46 of 54) of cases compared to 10% (1 of 10) of cases with depression. Specific information was obtained from EEG/EP studies that helped differentiate the various causes of dementia in three cases. In CEEG/EPM studies, a pattern of relative suppression of alpha activity or suppressed auditory P300 amplitude in the posterior parietal regions was observed in 11 or 23 (48%) patients with Alzheimer's disease and 2 of 31 (6%) patients with other forms of dementia. None of the depressed patients demonstrated such changes. Based on the present study, it appears that computerized techniques may hold promise as an adjunct to standard EEG evaluation of patients with mild cognitive change in whom diagnosis of dementia or depression is in doubt. Although standard EEG rarely demonstrates characteristic changes that may help differentiate causes of dementia, CEEG/EPM appears to demonstrate, on occasion, abnormalities in the posterior temporal and parietal regions in patients with a diagnosis of probable Alzheimer's disease and rarely in other forms of dementia or depression.
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PMID:Computerized electroencephalography in the evaluation of early dementia. 264 Dec 70


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