Effects of aging and dementia upon recent visuospatial memory

In two experiments, a total of 20 young normals, 29 elderly normals, and 76 elderly demented subjects were administered a computerized delayed visuospatial recall task. Subjects were instructed to remember which room of a 25-room house had a light on in the window. A choice reaction time task was interposed during the delay interval (0–120 seconds) between stimulus presentation and recall. The test was designed to be (1) face valid-relevant to the subjects' everyday lives, (2) sensitive and specific to the cognitive decline associated with senile dementia of the Alzheimer's type (SDAT), and (3) comparable to animal memory tests. Immediate recall of the spatial location of a single stimulus was found to be deficient in severely demented subjects only, and all groups exhibited a decline in recall accuracy with increasing delay intervals. This decline in recall accuracy was greatest in severely demented subjects, smaller in less demented subjects, still smaller in aged normals, and smallest in young normals. No significant forgetting of spatial location occurred between 30 and 120 seconds after stimulus presentation. Increasing stimulus number decreased recall accuracy in all groups and the elderly and elderly demented subjects were more sensitive to the increase in stimulus load than the young normals. Choice reaction time also proved sensitive to age and severity of dementia. Correlation analyses demonstrated that delayed spatial recall (as well as choice reaction time) is highly correltated with clinically evaluated global cognitive status, as well as with tests of verbal recall. These results confirm previous reports that spatial recall is impaired by both age and SDAT. It is concluded that this test procedure and others applying similar approaches should be useful in the assessment of age-related cognitive dysfunction and in the evaluation of potential pharmacological treatments for these disorders.     

Effects of aging and dementia upon recent visuospatial memory

In two experiments, a total of 20 young normals, 29 elderly normals, and 76 elderly demented subjects were administered a computerized delayed visuospatial recall task. Subjects were instructed to remember which room of a 25-room house had a light on in the window. A choice reaction time task was interposed during the delay interval (0–120 seconds) between stimulus presentation and recall. The test was designed to be (1) face valid-relevant to the subjects' everyday lives, (2) sensitive and specific to the cognitive decline associated with senile dementia of the Alzheimer's type (SDAT), and (3) comparable to animal memory tests. Immediate recall of the spatial location of a single stimulus was found to be deficient in severely demented subjects only, and all groups exhibited a decline in recall accuracy with increasing delay intervals. This decline in recall accuracy was greatest in severely demented subjects, smaller in less demented subjects, still smaller in aged normals, and smallest in young normals. No significant forgetting of spatial location occurred between 30 and 120 seconds after stimulus presentation. Increasing stimulus number decreased recall accuracy in all groups and the elderly and elderly demented subjects were more sensitive to the increase in stimulus load than the young normals. Choice reaction time also proved sensitive to age and severity of dementia. Correlation analyses demonstrated that delayed spatial recall (as well as choice reaction time) is highly correltated with clinically evaluated global cognitive status, as well as with tests of verbal recall. These results confirm previous reports that spatial recall is impaired by both age and SDAT. It is concluded that this test procedure and others applying similar approaches should be useful in the assessment of age-related cognitive dysfunction and in the evaluation of potential pharmacological treatments for these disorders.     

Cognitive impairments in depression

Depressed patients perform poorly on memory tests. This may reflect a failure to employ encoding strategies that facilitate recall or a generalized inability to allocate cognitive effort to more difficult tasks. Inpatients with major depression or personality disorders and age- and IQ-matched normal controls were administered an automatic frequency of occurrence test and verbal paired associated recall and recognition memory tests. There was no difference in frequency judgments among the subject groups. Both depressed and personality disordered groups recalled and recognized fewer words than normal subjects, with the depressed subjects tending to recall and recognize the fewest words. There was a strong effect of task difficulty on memory performance but this effect was consistent across subject groups. These findings suggest that the poorer performance of depressed patients on memory tests reflect basic memory impairments rather than a general inability to allocate cognitive effort to more demanding tasks. However, these impairments may not be specific to depression but may reflect general effects of psychopathology on memory.     

Genuine memory deficits in dementia

Controlled learning with effective cued recall is needed to distinguish between genuine memory deficits due to impairment of specific memory processes and apparent memory deficits due to impairment of other cognitive processes, such as attention, that can limit memory. Effective cued recall is needed for accurate measurement of memory in the elderly because cued recall reveals learning not shown by free recall. When a search procedure was used to control processing for effective encoding and cued recall, nondemented elderly adults recalled all or nearly all 16 items on each trial. Decreased recall by demented patients even after they carried out the same effective processing showed genuine memory impairment that was not due to other cognitive deficits. Cued recall was better than either free recall or recognition in discriminating elderly persons with dementia from those without dementia and by itself accounted for 75 % of the variation in dementia status. Cued recall was especially useful for identifying patients with mild to moderate dementia who were not identified by free recall. It is proposed that elderly persons who have decreased cued recall of a 16‐item list after controlled learning have genuine memory impairment and therefore are likely to be demented because other causes of amnestic syndromes are relatively infrequent in the aged. Controlled learning with effective cued recall should be useful for screening of elderly persons for dementia.     

Recall and recognition memory deficits in depression.

The aim of the present study was to establish the nature of memory deficits of depressive subjects in word learning tests. A word learning test consisting of 1, 3 or 5 learning trials was used. We found that patients were characterized by inferior memory recall compared to controls when 5 learning trials were given. Patients performed significantly slower than controls on a recognition test but both patients and controls recognized the same number of words. This suggests that the memory deficits that are present in many depressive subjects may be restricted to impaired active retrieval from memory. A second experiment revealed that recognition memory and delayed recall as well as immediate recall were impaired in depressive patients after 1 learning trial. These short-comings vanished after 3 trials, except for immediate recall. These data suggest that not only retrieval but also encoding of information into memory may be impaired in depression, especially in the beginning of a task when demands on cognitive effort are high. The results are discussed in terms of resource allocation and demands on effort that may change in the course of a task.     

Different trait markers for schizophrenia and bipolar disorder: a neurocognitive approach.

BACKGROUND: The aim of this study was to assess visual information processing and cognitive functions in unaffected siblings of patients with schizophrenia, bipolar disorder and control subjects with a negative family history. METHODS: The siblings of patients with schizophrenia (N = 25), bipolar disorder (N = 20) and the controls subjects (N = 20) were matched for age, education, IQ, and psychosocial functioning, as indexed by the Global Assessment of Functioning scale. Visual information processing was measured using two visual backward masking (VBM) tests (target location and target identification). The evaluation of higher cognitive functions included spatial and verbal working memory, Wisconsin Card Sorting Test, letter fluency, short/long delay verbal recall and recognition. RESULTS: The relatives of schizophrenia patients were impaired in the VBM procedure, more pronouncedly at short interstimulus intervals (14, 28, 42 ms) and in the target location task. Marked dysfunctions were also found in the spatial working memory task and in the long delay verbal recall test. In contrast, the siblings of patients with bipolar disorder exhibited spared performances with the exception of a deficit in the long delay recall task. CONCLUSIONS: Dysfunctions of sensory-perceptual analysis (VBM) and working memory for spatial information distinguished the siblings of schizophrenia patients from the siblings of individuals with bipolar disorder. Verbal recall deficit was present in both groups, suggesting a common impairment of the fronto-hippocampal system.     

Influence of age and executive functioning on verbal memory of inpatients with depression

BACKGROUND: Despite many studies demonstrating memory and executive impairments in young and old depressed patients, the relationships between age, executive functioning and memory have not been evaluated in depression. The aim of this study was to investigate if older patients were more vulnerable than younger patients to the impact of depression on memory and if the differences between young and old depressed could be related to executive functioning. METHODS: Forty-nine inpatients, with unipolar and bipolar depression, ranging in age from 19 to 72 years were compared with 70 controls on a verbal memory task. Age cut-off of 45 years was used as a categorical variable to divide subjects into subgroups. A subset of patients (n=41) was also evaluated with the modified version of the Wisconsin Card Sorting Test and separated into a non-dysexecutive group and a group of patients with mild-executive impairment. RESULTS: Depressed patients exhibited memory deficits with a pattern of memory failure -- impaired free recall and normal cued recall and recognition -- interpreted as a retrieval problem. Both age and executive function influenced memory performance in depression, however neither group x age interaction nor age x executive status interaction were significant. Multiple regression analysis showed that free recall scores were related to age and psychomotor retardation in depressed patients. CONCLUSION: Age and executive functioning have different influences on the memory performance of depressed patients. Our findings support an 'executive memory decline hypothesis' in young as well as old depressed patients. The memory deficits in depression may be associated with both trait and state factors and raise questions about the long-term cognitive functioning of patients with recurrent affective disorders.     

Cognitive function in aged ovariectomized female rhesus monkeys

To determine whether ovariectomy exacerbates age-related cognitive decline, the performance of 6 aged monkeys that had been ovariectomized early in life (OVX-Aged) was compared to that of 8 age-matched controls with intact ovaries (INT-Aged) and that of 5 young controls with intact ovaries (INT-Young) in tasks of visual recognition memory, object and spatial memory, and executive function. The OVX-Aged monkeys were marginally more impaired than the INT-Aged monkeys on the delayed nonmatching-to-sample with a 600-s delay. In contrast, they performed significantly better than the INT-Aged controls on the spatial condition of the delayed recognition span test. The hypothesis that prolonged estrogenic deprivation may exaggerate the age-related decline in visual recognition memory will require additional support. However, the findings suggest that long-term ovariectomy may protect against the development with aging of spatial memory deficits.     

The effects of nicotine upon memory and problem solving performance

This study examined the effects of 4 mg nicotine and placebo upon problem solving performance in word and number tasks, and subsequent recall and recognition of the answers to these problems. The results demonstrated that the drug had no effect upon the subject's ability to generate the correct answers to the problems, but that immediate and delayed recall and recognition were significantly impaired. These data clearly do not support the view that nicotine, without exception, enhances information processing, and it was suggested that the effects of nicotine upon information retrieval may be specific to tasks which assess episodic memory in the absence of retrieval cues or a problem solving context.     

Amnestic mild cognitive impairment: difference of memory profile in subjects who converted or did not convert to Alzheimer's disease

Episodic long-term, short-term, and implicit memory were investigated in 79 elderly subjects who fulfilled criteria for the amnestic form of mild cognitive impairment (a-MCI; i.e., by having an idiopathic amnestic disorder with absence of impairment in cognitive areas other than memory and without confounding medical or psychiatric conditions) and who developed Alzheimer's disease (AD) after 2 years as well as in 111 subjects affected by a-MCI who did not develop dementia. Results document a memory profile in a-MCI subjects characterized by preserved short-term and implicit memory and extensive impairment of episodic long-term memory. In virtually all episodic memory indexes examined (learning, forgetting, recognition abilities), a-MCI subjects who converted to AD were more severely impaired than were subjects who did not become demented. This memory profile, which closely resembles that exhibited by amnestic patients with bilateral mesial-temporal lobe lesions, confirms a precocious phase in preclinical AD characterized by selective involvement of mesial-temporal areas and worsening of the memory impairment as atrophic changes progress in hippocampal structures. In this context of pervasive episodic memory impairment, tests assessing the free recall of verbal material following a delay interval demonstrated the greater sensitivity to memory deficits of a-MCI subjects who developed AD.     

Functional irregularities of short-term and long-term memory storage in patients with Parkinson's disease and Huntington's disease.

Memory performance of Parkinson's disease patients (PD patients). Huntington's disease patients (HD patients) and healthy subjects were compared by a single-trial free recall task following the presentation of a stimulus list consisting of 30 nouns. The patient groups were categorized according to the severity of the disease into mild, moderate, and severe. Healthy subjects reproduced significantly more words than PD and HD patients, while the two patient groups did not differ in the total number of words reproduced. The differences between healthy and demented subjects are attributed to the impaired functional capacity of long-term memory; there were significant differences between healthy subjects and patients as well as between PD and HD patients. When taking the severity of the disease into consideration, varied influence on the capacity of long-term memory for PD and HD patients was found. Concerning short-term memory, neither a difference between healthy subjects and patients nor between both patient groups could be established. An effect of the severity of the disease could not be proven.     

Rey Auditory-Verbal Learning Test: the effects of age and gender, and norms for delayed recall and story recognition trials.

Immediate recall and three measures of delayed memory performance were evaluated in 134 healthy adults aged 16-76. Gender of subjects had no Influence on performance for any of the acquisition or retention trials. Age influenced acquisition as memory load began to exceed five to six words, with older subjects exhibiting decreased capacity. There was little loss of information between the immediate and delayed recall trials for any age group. Norms for a 30-min delayed recall trial, commission errors on delayed recall, and delayed recognition using Rey's story recognition procedure are presented, and implications for clinical use are discussed.     

Memory encoding and retrieval in frontotemporal dementia and Alzheimer's disease

Memory encoding and retrieval strategies were assessed in patients with behavior-executive variant frontotemporal dementia (FTD), language variant FTD, and Alzheimer's disease (AD) using verbal and visuospatial supraspan learning tests. FTD patients obtained higher free recall, cued recall, and recognition scores than AD patients. Comparison of free recall scores with cued recall and recognition scores was similar in the 3 dementia groups. Groups did not differ in semantic clustering strategies during learning, but serial-order recall was more common in FTD patients. These data do not support the idea that FTD patients' poor memory is due to a selective retrieval disorder, though FTD patients may fail to implement sophisticated organizational strategies during learning. FTD patients' retained capacity for encoding new information into long-term declarative memory is likely due to relatively spared medial temporal lobe involvement.     

Verbal and nonverbal memory processing in patients with obsessive-compulsive disorder: its relationship to clinical variables

Memory deficits have been reported in several neuropsychological studies of obsessive-compulsive disorder (OCD). Dysfunction in nonverbal memory has been consistently reported, whereas findings on verbal memory are more heterogeneous. The authors studied 50 patients with OCD who were matched for sex, age, educational level, and hand dominance with 50 healthy controls (HC). Cognitive performance in both groups was assessed on verbal and nonverbal memory tasks, and several clinical variables were also assessed in the patient group. Patients with OCD showed a pattern of cognitive dysfunction with alterations in areas of nonverbal memory (recall and recognition), and verbal memory (learning and recall). Older age at onset of OCD was associated with poorer performance on verbal memory tasks. Low scores on some verbal memory tasks were associated with severity of OCD, and nonverbal memory was influenced by depressive symptoms. The study suggests the existence of dysfunction in the execution of verbal and nonverbal memory tasks in OCD; the influence of clinical variables depends on the specific neuropsychological function.     

The effects of interference on verbal learning in multiple sclerosis.

Thirty multiple sclerosis (MS) patients were compared with 30 matched (age and education) controls and were asked to learn and recall 20 target words that were placed among 24 distracter words. Targets and distracters were printed on different colored cards, and the subjects were asked to read each word aloud and recall the target words. This task was repeated four times. The MS patients recalled significantly fewer words across the four trials. A second list without distracters was presented for two trials, and there were no significant differences between the groups' recall. Subsequent recall (short delay and long delay) for List 1 revealed significantly poorer recall for the MS group and significantly poorer cued recall but not recognition memory. Retrieval processes were implicated such as source memory, or contextual stamping, rather than encoding mechanisms.     

Neuropsychological functioning in HIV-positive African-American women with a history of drug use.

This preliminary investigation examined neuropsychological performance in a sample of human immunodeficiency virus (HIV)-positive and HIV-negative African-American women with a history of drug use. The study population was comprised of 10 HIV-negative, 9 asymptomatic HIV-positive, 13 symptomatic HIV-positive, and 10 acquired immunodeficiency virus (AIDS) patients. A neuropsychological battery designed to assess attention, psychomotor processing, verbal memory, and visual memory was administered to participants. No evidence of HIV-related cognitive impairment was found in patients in the early stages of HIV infection. Multivariate analyses of variance revealed significant deficits in psychomotor processing and verbal recall in persons with AIDS. These individuals showed greater difficulty in tasks requiring maintained attention and performed poorly on measures of immediate and delayed verbal recall. In contrast, HIV status was not related to visual memory, verbal recognition, or the number of errors made during a verbal recall task. The pattern of cognitive deficits observed in persons with AIDS resembles that commonly associated with subcortical pathology. The cognitive deficits observed were not related to depression or recentness of drug use.     

Multiple inputs to episodic memory: words tell another story

Seven patients with semantic dementia were asked to recall and recognize 10-word lists of object-name vocabulary preselected as either still "known" (correct picture naming and word-picture matching) or now "unknown" (incorrect picture naming and word-picture matching) to each individual patient. The patients showed a significant advantage for known words in immediate free recall after several learning trials and also in delayed recall and recognition. The majority of errors of commission for known words were semantic, whereas phonological errors, especially blends of target words, were produced in the unknown condition. These findings support claims that (a) multiple inputs from semantic and perceptual systems support episodic memory and (b) success in verbal and nonverbal episodic memory tasks is differentially dependent on semantic and perceptual information.     

Cognitive functioning in depression

Verbal learning and memory, and recognition of famous faces, were assessed in 21 non-demented inpatients with RDC endogenous depression. Severity of depression was related to attention span, and patient age was related to measures of learning and recall. However, even in this severely depressed sample, verbal learning/memory measures were not below normative values. Facial recognition was significantly impaired relative to test norms. The results suggest that mild impairment in the early stages of verbal information encoding, and more marked impairment in the recognition of famous faces, may be associated with depression. These impairments differ from the cognitive changes associated with aging.     

Productive naming and memory in depression and Alzheimer's type dementia.

Patients with mild to moderate dementia of the Alzheimer's type (DAT), patients with major depression, and normal controls completed tests of productive naming and verbal recall memory. Both depressed and DAT patients demonstrated reduced verbal fluency on productive naming tasks, indicating limited utility of such tasks in differential diagnosis. There was a stronger relationship between verbal fluency and memory in DAT patients than in depressed patients. The linguistic component as well as the requirement for cognitive speed may be important in explaining the deficit of DAT patients on productive naming tasks. In contrast, the speed component may be particularly important for depressed patients whose poor performance may reflect a motivational deficit.     

Rats spontaneously discriminate purely visual, two-dimensional stimuli in tests of recognition memory and perceptual oddity

Animal models have been central to advances made in understanding the neural basis of human cognition, but maximizing the use of animal models requires tasks that match those used to assess human subjects. Tasks used in humans frequently use visual 2-dimensional stimuli, assess 1-trial learning, and require little pretraining. This article describes novel versions of 2 tasks for the rat, spontaneous object recognition and spontaneous oddity preference, both of which use purely visual, 2-dimensional picture-card stimuli, test 1-trial learning, and require no pretraining. Rats showed robust memory for a variety of picture-card stimuli, demonstrating almost no loss of memory for some of the stimulus types even after a 2-hr delay period. Rats were able to show spontaneous oddity preference for all 3 visual stimulus types tested (photos, shapes, and patterns), as well as for 3-dimensional objects. These 2 tasks are quick to administer, involve no fearful learning associations, and require a simple apparatus. They may be particularly useful for high-throughput pharmacological or genetic screening using rodent models.