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PubMed2000

[Neuropsychological deficits in depressive disorders].

Neuropsychological deficits are considered a significant feature of depression both for their differential value in the diagnostics and the underlying pathophysiology of depressive disorders. The studies reviewed in the present paper predominantly focus on memory disorders as well as frontal-lobe associated dysfunctions such as deficits of attentional performance and executive functions. Despite heterogeneous results in the literature, there is emerging evidence that executive functions and anterograde memory performance are those domains predominantly affected in depressive disorders. The fact that not all depressive patients display neuropsychological deficits rather indicates a dominant role of moderating variables. We discuss the following variables possibly intervening with type and degree of neuropsychological dysfunction: [1] severity and remission of depressive disorders, [2] age of patients and age at the first manifestation of a depressive disorder, [3] psychological factors such as motivation and coping with failure, [4] type and efficacy of antidepressive drug treatment, [5] duration of the stay as inpatients, [6] number of depressive episodes, and [7] gender. Furthermore, we discuss the theory of a dysfunction of fronto-striatal circuits as an underlying mechanism of depressive disorders. The majority of neuropsychological findings seem to support this theory.

Attention↗
PubMed2001

The diagnostic value of EEG in Alzheimer disease: correlation with the severity of mental impairment.

The aim of our study was to analyze EEG changes in patients with Alzheimer disease (AD) and to determine how closely EEG reflects the progression of mental impairment in people with AD. Ninety-five patients with probable AD according to National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria treated in our Clinic for Memory Disorders were selected for this study. Patients were divided into three subgroups with mild, marked, and severe dementia according to the results of psychometric scales. The EEG findings were classified using an eight-degree scale according to the background activity, presence and amount of theta and delta waves, focal changes, lateralization of focal changes, synchronization, and presence of sharp and spike waves. A significant correlation between the degree of EEG abnormalities and cognitive impairment was found. We did not observe any correlation between the presence of delta waves and the results of neuropsychological tests. Our study revealed an important diagnostic value of EEG in the estimation of the severity of dementia parallel to psychometric scales.

Adult↗
PubMed1987

Effects of propentofylline on disorder of learning and memory in rodents.

Effects of a newly synthesized xanthine derivative propentofylline (3,7-dihydro-3-methyl-1-(5-oxohexyl)-7-propyl-1H-purine-2,6-dione) on learning and memory of rodents were examined in the two different paradigms. In a shuttle box active avoidance paradigm, propentofylline (25 mg/kg/day, p.o.) improved the decreased learning ability of 12-month-old spontaneously hypertensive rats. Normotensive Wistar-Kyoto rats at a comparable age showed rapid acquisition of avoidance learning, which was not influenced by propentofylline. Step-down passive avoidance task was carried out as the other paradigm. The protein synthesis inhibitor cycloheximide (CXM) induced amnesia in young adult mice. Propentofylline improved the memory deficit when intraperitoneally administered 30 min before the retention test, and it also prevented the development of amnesia when injected 15 min before CXM. These results suggest that propentofylline ameliorates the disturbed learning and memory.

Amnesia↗
PubMed1988

[Disordered long-term memory in mice as affected by azidothymidine].

An action of azidothymidine (AZT) on the acquisition of passive avoidance behaviour was studied in mice. Intraperitoneal administration of AZT (5-80 mg/kg) inhibited markedly the formation of passive avoidance behaviour. AZT had amnestic effect when administered 1 hour before learning, immediately after learning, 1 to 3 hours, but not 5 hours after learning. Administration of AZT 1 hour before learning had no influence on passive avoidance behaviour tested 24 hours later. The first signs of amnesia appeared 48 hours after learning and the effect was maximum during testing one week after learning. It is suggested that this effect of AZT may indicate the necessity of reverse transcription in the nervous cells for the consolidation of long-term memory.

Animals↗
PubMed1987

Disordered auditory short-term memory in man and event-related potentials.

Four patients with conduction aphasia and impaired auditory but relatively preserved visual digit spans were tested in a task of short-term memory, a digit probe identification task, in both the visual and auditory modalities. Five age-matched normal subjects served as controls. Behavioural measures of response accuracy and reaction time and scalp derived event-related potentials were determined as a function of the number of items to be remembered. These measures were also recorded in a task requiring the detection of infrequent stimuli ('oddball' paradigm). The patients' performance and event-related potential wave forms for the 'oddball' task were no different from those of the controls. In the digit probe identification tasks the patients showed a reduction in amplitude of a positive component at a latency of approximately 450 ms (P450) of the event-related potential to correctly identified probes in the auditory modality. This component was within normal limits with visual testing. There was an inordinate increase in the patients' reaction time to auditory but not visual stimuli when the number of items to be remembered increased from one to three. Event-related potentials were also analysed as a function of speed of reaction time, position of the matching item in the stimulus presentation set and whether the probe was correctly identified as being in-set or out-of-set. Event-related potentials associated with fast reaction times in the auditory task when a single item was presented were no different between patients and controls, indicating that patients were capable of both performing normally and generating normal potentials on some trials. The data suggest that the deficit in auditory short-term memory in these patients occurs during stimulus classification.

Adult↗
PubMedDate not supplied

[The nootropic correction of disorders in learning and memory processes induced by extreme exposures].

Experiments on rats demonstrated that the low-intensity electromagnetic field (12.6 cm, 2375 MHz, power density 1 mW/cm2), motion sickness, and electroconvulsive shock provoked the retrograde amnesia in the passive avoidance test. The oxyracetam (100 mg/kg, i.p.), aniracetam (50 mg/kg, i.p.), nooglutil (50 mg/kg, i.p.), meclofenoxate (50 mg/kg, i.p.), pyracetam (200 mg/kg, i.p.), and GABA (200 mg/kg, i.p) prevented the memory-impairing effect of all these extreme factors. On the contrary, the N-acetylglycinamide, semax, and other nootropic drugs were effective only under one or two extreme conditions.

Animals↗
PubMed1999

Memory suppressor genes: enhancing the relationship between synaptic plasticity and memory storage.

Memory suppressor genes encode proteins that act as inhibitory constraints to impede memory storage. The study of memory suppressor genes is important not only for understanding the link between synaptic plasticity and learning but also for identifying potential targets for future pharmaceuticals to treat memory disorders. This article first reviews the evidence for proteins that impede memory storage from work in invertebrates and then explores recent evidence for the existence of memory suppressor genes in vertebrates in the context of hippocampus-dependent forms of memory. In Aplysia, memory suppressor gene products act at each step in long-term facilitation: in the cytoplasm to regulate kinase activity, in the nucleus to alter the activity of transcriptional regulatory proteins, and on the cell surface to modulate cell-cell interactions. Studies of genetically modified Drosophila have provided behavioral evidence for the existence of memory suppressor genes. One of the best candidates for a neuronal mechanism underlying learning is long-term potentiation (LTP), which has been extensively studied in the mammalian hippocampus. Recent work has identified a number of putative memory suppressor gene products that act in the hippocampus at the levels of LTP induction, regulation of intracellular signaling cascades, and transcriptional control. Using these gene products as tools to study enhancements rather than deficits in LTP and learning may generate more precise information about the relationship between synaptic plasticity and behavioral learning. The study of mammalian memory suppressor genes may provide insights into alleviating the learning and memory deficits that accompany both normal aging and a variety of human disorders.

Animals↗
PubMed1987

Cognitive evoked potentials and disorders of recent memory.

P3 potentials evoked by spoken words were recorded from seven patients with disorders of recent memory and seven age-matched controls. Inclusion criteria included a clearly identifiable P3 to pure tone stimuli. Absence or marked decrement of P3 to word stimuli was seen in the patients even though they could perform the word task. The results are consistent with an encoding disorder and failure in elaboration of information processing.

Adult↗
PubMed1994

[Short term memory and severe language disorders in the child].

Memory, and particularly short-term memory or "working memory" (Baddeley), is involved in language acquisition in children. We have studied short-term memory, with verbal-and non verbal tests, of 8 children suffering from developmental dysphasia compared with other ones, matched in terms of age and performance I.Q. (W.I.S.C.-R.). The digit span did not significantly differ in the two groups, while the visuo-spatial span was lower in the dysphasic group. The memorization of a list of monosyllabic words by dysphasic children was poor in the absence of visual presentation and improved by it. Differences between dysphasic and control-children are unlikely to be due to speech rate which does not significantly differ from one group to the other one. The results suggest the existence, in language disordered children, of cognitive functions disorders much more important than those directly involved in the speech production.

Case-Control Studies↗
PubMed2001

Assessment of memory in neurogenic communication disorders.

The evaluation of memory in adults with neurogenic communication disorders is complicated by the fact that traditional memory assessment emphasizes verbal content. Also, standardized test procedures often include long and complex instructions that place heavy comprehension demands on clients. This article provides an overview of these and other issues to consider when assessing memory in adults with neurogenic communication disorders. Specifically, this article will include (1) a description of the concept of memory for clinical assessment and definitions of common terms; (2) a general review of assessment methods and selected tests; and (3) considerations for assessing adults with neurogenic communication disorders.

Brain↗