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The effect of distractor strength versus rate of item presentation on retention in schizophrenics.

Predictions made from Chapman & McGhie's attentional dysfunction theory of schizophrenia were compared with those made from Yates' slow information processing theory. Retention in a free-recall, short-term memory task was studied with 20 chronic nonparanoid schizophrenics and 20 psychiatric controls matched on age, educational level and intelligence as subjects. Schizophrenics performed consistently poorer than controls, but no differences between groups were found as a function of either variation in distractor strength or in item presentation rate. Thus, neither theory was supported, but several uncontrolled aspects of the task variable were suggested as possible reasons for some of these conflicting findings.

Adult↗

Age-associated memory changes in adults with williams syndrome.

Age-associated changes on measures of episodic and working memory were examined in 15 adults with Williams Syndrome (WS; M age = 48.3 years, SD = 14.7; M IQ = 62.9, SD = 8.5) and their performance was compared to that of 33 adults with mental retardation (MR) with unspecified etiologies (M age = 54.2 years, SD = 8.9; M IQ = 61.7, SD = 6.5). Among the group with WS, older adults were significantly poorer than younger adults on the free recall task, a measure of episodic memory. Although this finding is consistent with normal aging, it occurred at a chronologically early age in adults with WS and was not found in their peers with unspecified MR. Although both groups showed small declines with age on a backward digit span task, a measure of working memory, for the group with WS the rate of decline on backward digit span was slower as compared to their performance on the free recall task. The findings from this study indicate a chronologically early and precipitous age-associated decrease in long-term, episodic memory in adults with WS.

Adult↗

Interrater agreement for diagnosis of Alzheimer's disease: the MIRAGE study.

There are standardized criteria to assist in the diagnosis of Alzheimer's disease (AD), a disorder that lacks unique clinical, morphologic, or biochemical features. Diagnostic reliability of single groups of investigators using these criteria is moderate to substantial. In this study, seven clinicians at separate sites established a criteria-based diagnosis in 42 consecutive memory disorder patients participating in a national genetic epidemiologic study using a quantitative multiaxis AD rating scale (ADRS) that incorporates NINCDS/ADRDA criteria, reliability of information, and comorbidity. Reliability, measured by a generalized kappa statistic for more than two raters, was substantial (0.63 +/- 0.13) when the subjects were grouped as "AD" (probable or possible) versus "not AD," but somewhat lower (0.52 +/- 0.10) when subjects were classified as probable AD, possible AD, or not AD. There was unanimous agreement for two-thirds of the subjects using a dichotomous classification scheme. These findings suggest that the ADRS is a useful diagnostic instrument for multicenter studies.

Alzheimer Disease↗

[Pharmacological treatment of Korsakoff's psychosis: a review of the literature and experience in two cases].

INTRODUCTION: Korsakoff s psychosis (KP) is a relatively frequent pathological condition in our community that has been infradiagnosed. The most common cause is chronic alcohol consumption, although it can be brought about by other aetiologies accompanied by vitamin deficiencies. The lack of thiamine entails an alteration in the synthesis of neurotransmitters, which provides the neurochemical foundation for the specific cognitive impairment that defines the syndrome. AIMS: To evaluate the application of pharmacological treatments, in accordance with the neurochemical disorders described in the literature, and report our experience in two cases treated with anticholinesterases. CASE REPORTS: 1) Female aged 47, with a history of addiction to alcohol. Following Wernicke s encephalopathy, which improved with parenteral thiamine, she presented a memory disorder compatible with KP. After two months treatment with donepezil, a cognitive improvement was observed in the neuropsychological tests. 2) Male aged 77, who presented KP a month after being diagnosed and treated for a post encephalitic vasculitis caused be varicella zoster virus. His cognitive and functional condition improved after 3 months treatment with donepezil. DISCUSSION AND CONCLUSIONS: There are not enough studies in the literature with representative samples that consider the effects of thiamine or of other forms of treatment on cognitive impairment in KP. Noradrenaline, serotonin, glutamate and acetylcholine have been proposed in the pathogeny of the syndrome. Based on experiences gained in cholinergic disorders, two cases responded to treatment with donepezil. Effective treatment must be based on a combination of aetiological and pharmacological treatment, and cognitive rehabilitation.

Aged↗

Comparison of the neuropsychological deficits associated with early and advanced Huntington's disease.

Patients with "recently" diagnosed Huntington's Disease (RHD) were compared on a neuropsychological test battery to patients who have had the disease three to 15 years (AHD) and to intact controls. While the patients with HD showed general nonfocal deficits on the Wechsler Adult Intelligence Scale, the Wechsler Memory Scale, and tests of short-term memory and verbal fluency, the patients with RHD had focal deficits that stressed their memory deficits. The patients with RHD had IQs within the normal range, but their memory quotients, their performance on short-term memory tests, and their ability to search and retrieve from long-term memory were severely imparied. These results suggest that the cognitive deficits of patients with HD do not develop uniformally; memory disorders are early focal signs that precede the patients' more widespread intellectual deterioration.

Adult↗

Memory-related neural systems in Alzheimer's disease: an anatomic study.

In the primate brain, there are strong connections among the entorhinal cortex, the hippocampal formation, and the amygdala, 3 structures of the ventromedial temporal lobe that are related to memory function. Because memory impairment is a central feature of Alzheimer's disease, we examined the probable cells of origin and terminal zones of these connections in the brains of humans affected by the disease, using thioflavine S, Alz-50, and anti-A4 amyloid protein immunocytochemistry. Specific cytoarchitectural areas and lamina that give rise to projections from the entorhinal cortex, the hippocampal formation, and the amygdala consistently contained neurofibrillary tangles. The terminal zones of many of these projections contained neuritic plaques, Alz-50-positive neuritic alterations, and A4 deposition. Other cytoarchitectural areas and lamina, sometimes immediately adjacent, were consistently spared from these Alzheimer changes. This pattern of Alzheimer-related alterations would disrupt projections among the entorhinal cortex, hippocampal formation, and amygdala at multiple sites, and also disrupt projections between these structures and cortical and subcortical targets. In functional terms, this pattern of structural damage is likely to be as devastating as bilateral destruction of the ventromedial temporal lobe, and thus contribute substantially to the memory disorder seen in this condition.

Aged↗

Perspectives on depression, mild cognitive impairment, and cognitive decline.

CONTEXT: The public health implications of depression and cognitive impairment in late life are enormous. Cognitive impairment and late-life depression are associated with increased risk for subsequent dementia; however, investigations of these phenomena appear to be proceeding along separate tracks. OBJECTIVES AND DATA SOURCE: The National Institute of Mental Health organized the conference "Perspectives on Depression, Mild Cognitive Impairment, and Cognitive Decline" to consider how the varied perspectives might be better integrated to examine the associations among depression, mild cognitive impairment, and cognitive decline and to illuminate the common or distinct mechanisms involved in these associations. DATA SYNTHESIS: The following 2 broad questions were addressed: (1) What gaps in our knowledge have the greatest public health significance? (2) Can we more efficiently use our research dollars and participant resources to fill these gaps? Meeting participants included grantees from the National Institute of Mental Health and the National Institute on Aging and program staff from the National Institute of Mental Health, the National Institute on Aging, and the National Institute of Neurological Disorders and Stroke. CONCLUSIONS: One of the most important recommendations to emerge from the meeting discussions is for increased collaboration among clinical and epidemiological investigators whose work focuses in the area of depression with those working primarily in the area of memory disorders. Directions for future research were identified.

Aged↗

In search of the neurobiological underpinnings of the differential outcomes effect.

Correlating unique rewards with to-be-remembered events (the Differential Outcomes Procedure [DOP]) enhances learning and memory performance in a range of species. Recently, we have demonstrated that the DOP can be used to reduce or eliminate the learning and memory impairments associated with animal models of amnesia and dementia. This powerful phenomenon, the Differential Outcomes Effect (DOE), has led to the question: How does such a simple manipulation exert such dramatic influence on learning and memory performance? A revised two-process account of the DOE states that using the DOP results in the activation of reward expectancies through Pavlovian mechanisms. The use of unique reward expectancies alters the nature of cognitive processing used to solve discrimination tasks. The change in cognitive processing is represented by utilization of a different memory system than that commonly used to acquire and remember information when a Nondifferential Outcomes Procedure (NOP) is used. Using neurochemical manipulations, it has been demonstrated that different, potentially independent, brain systems modulate memory performance when subjects are trained with a NOP versus a DOP. This memory-based DOP/NOP distinction resembles other dissociative memory theories in which two psychological processes are purportedly served by distinct neurobiological mechanisms. In addition, such results have important ramifications for the treatment of memory disorders because they demonstrate that stimulus and behavioral manipulations, like drugs, can influence neurotransmitter functioning.

Aging↗

Eyeblink conditioning in the infant rat: an animal model of learning in developmental neurotoxicology.

Classical conditioning of the eyeblink reflex is a relatively simple procedure for studying associative learning that was first developed for use with human subjects more than half a century ago. The use of this procedure in laboratory animals by psychologists and neuroscientists over the past 30 years has produced a powerful animal model for studying the behavioral and biological mechanisms of learning. As a result, eyeblink conditioning is beginning to be pursued as a very promising model for predicting and understanding human learning and memory disorders. Among the many advantages of this procedure are (a) the fact that it can be carried out in the same manner in both humans and laboratory animals; (b) the many ways in which it permits one to characterize changes in learning at the behavioral level; (c) the readiness with which hypotheses regarding the neurological basis of behavioral disorders can be formulated and tested; (d) the fact that it can be used in the same way across the life-span; and (e) its ability to distinguish, from normative groups, populations suffering from neurological conditions associated with impaired learning and memory, including those produced by exposure to neurotoxicants. In this article, we argue that these properties of eyeblink conditioning make it an excellent model system for studying early impairments of learning and memory in developmental neurotoxicology. We also review progress that has been made in our laboratory in developing a rodent model of infant eyeblink conditioning for this purpose.

Animals↗

Biotin in the management of uremic neurologic disorders.

In 9 patients undergoing chronic hemodialysis for 2-10 years and suffering from encephalopathy (dialysis dementia) and peripheral neuropathy, 10 mg of biotin was given daily in three doses for 1-4 years. Within 3 months there was a marked improvement in all patients in respect to disorientation, speech disorders, memory failure, myoclonic jerks, flapping tremor, restless legs, paresthesia and difficulties in walking. It is recommended to start giving biotin regularly in any patient with advanced renal failure before severe neural or muscular lesions become manifest. The correlation of biotin with uremic neurologic disorders and the possible mechanism of its therapeutic action are discussed.

Biotin↗

[Endoscopic surgery of third ventricle lesions].

The endoscopic approach of the tumors of the third ventricle interests mainly the colloid cysts but also offers the possibilities of biopsies. Twenty two patients (16 men and 6 women, average age 41 years) presenting with hydrocephalus related to a tumor of the pineal area were treated by a ventriculostomy with attempt at biopsy : they are outside of the limits of this report. Twenty two other patients (15 men, 7 women, average age 39 years) were operated on from 1994 to 1999 for a colloid cyst, and 2 of them were admitted in emergency in sudden coma. The CT scan showed a colloid cyst (hyperdense in 16 patients) associated with an hydrocephalus, except for a patient previously shunted. The diameter of the cyst varied from 4 to 50 mm (average of 20 mm). All the patients were operated on using a rigid endoscope. Among the 20 patients presenting a tumor of the pineal area, a biopsy was possible only in 4 cases (20%). There were no hemorrhage nor neurological disorders. In all the cases, the size and the number of the specimens were sufficient to allow the histological diagnosis. For the patients presenting with colloid cyst, the average follow-up is 2 years. All the preoperative symptoms disappeared except for the memory disorders which were improved. The post-operative Evans index decreased significantly. No residual cyst was observed on the post-operative MRI in 14 patients (63%). Among these patients, an asymptomatic recurrence was observed and remained stable after 44 months of follow-up. A residual cyst was observed in 8 patients (36%), with a diameter from 5 to 25 mm (average 9 mm). No patient required a shunt procedure, and no patient presented hemorrhagic complication. Endoscopy is especially useful in the first line treatment of the colloid cysts of the third ventricle.

Adult↗