Memory dysfunction and word priming in dementia and amnesia.

Memory performance of patients with the clinical diagnosis of Alzheimer's disease was compared with performance of patients with alcoholic Korsakoff's syndrome and patients with Huntington's disease. Although all patient groups exhibited impairment on tests of verbal memory, only patients with Alzheimer's disease exhibited priming. Priming is an unconscious expression of recently encountered material, and it is intact even in severely amnesic patients. Because mildly demented patients with Alzheimer's disease exhibited impaired priming, damage to brain structures in addition to those damaged in the amnesic syndrome must occur at a relatively early stage of the disease process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do amnesics forget colours pathologically fast?

We tested amnesic and control subjects on a task which required the recognition of single, difficult to name colours, after delays ranging from 7 seconds to 120 seconds after performance of the two subject groups had been matched at the shortest delay by giving the amnesic patients longer study time. The amnesic patients showed abnormally fast forgetting over the two minute period. Furthermore, a subgroup of nine subjects with presumed damage to midline diencephalic structures (Korsakoff's syndrome) were found to forget as fast as a group of six subjects with presumed medial temporal lobe damage (herpes simplex encephalitis). These results contrast both with studies using the Huppert and Piercy procedure and those using the Brown-Peterson task, none of which have shown convincing evidence of accelerated forgetting in medial temporal lobe or diencephalic amnesia.     

Mammillary body and cerebellar shrinkage in chronic alcoholics with and without amnesia

Mammillary body and cerebellar atrophy have been described as postmorten neuropathologic markers of Korsakoff's syndrome. This study examined whether shrinkage in the mammillary bodies and cerebellum is present consistently in amnesic chronic alcoholics during life and whether the degree of abnormality in these patients differs from that in nonamnesic alcoholic and healthy controls. The severity of shrinkage in the mammillary bodies, cerebellar hemispheres, and cerebellar vermis visualizable on MRI scans was rated on a three-point scale in 33 chronic nonamnesic alcoholics, 9 amnesic alcoholics, and 20 healthy controls. Although both alcoholic groups showed significant mammillary body and cerebellar shrinkage relative to controls, the two patient groups did not differ from each other. Furthermore, four of eight amnesic patients in our sample did not demonstrate clinically significant mammillary body atrophy. These results suggest that alcoholism is associated with mammillary body and cerebellar tissue volume loss but do not provide evidence that these markers distinguish accurately between amnesic and nonamnesic patients. In addition, they suggest that visualizable mammillary body atrophy is not necessary for the development of amnesia in alcoholic patients.     

Cognitive impairment following frontal lobe damage and its relevance to human amnesia.

Whether frontal lobe pathology can account for some of the cognitive impairment oberved in amnesic patients with Korsakoff's syndrome was investigated. Various cognitive and memory tests were given to patients with circumscribed frontal lobe lesions, patients with Korsakoff's syndrome, non-Korsakoff amnesic patients, and control Ss. Patients with frontal lobe lesions were not amnesic. Nevertheless, they exhibited 2 deficits that were also exhibited by patients with Korsakoff's syndrome but not by other amnesic patients: (a) impairment on the Wisconsin Card Sorting Test and (b) impairment on the Initiation and Perseveration subscale of the Dementia Rating Scale. Thus, frontal lobe pathology can explain some of the cognitive deficits observed in patients with Korsakoff's syndrome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bilateral frontal lobe disease and selective delayed response deficits in humans.

Compared the performance of 6 male patients (aged 24–65 yrs) with frontal lobe disease; 17 amnesic male patients (12 with etiology of alcoholic Korsakoff's disease [mean age 53.6 yrs] and 5 with surgically treated ruptured anterior communicating artery aneurysm [mean age 45.6 yrs]), and 12 male alcoholic controls (mean age 39.7 yrs) with no memory impairment on delayed alternation (DA) and delayed response (DR) tasks, known to be sensitive to frontal lobe damage in nonhuman primates. Ss (except the Korsakoff and alcoholic Ss) completed the Wechsler Memory Scale, and all Ss completed the Wechsler Adult Intelligence Scale (WAIS) and the Wisconsin Card Sorting Test. Results show that bilateral frontal lobe damage was associated with impairment on both tasks. There was no relation between performances on DA and DR and performance on the Wechsler Memory Scale, strengthening the suggestion that the former tasks are not sensitive to anterograde amnesia in humans. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic homophone priming in patients with dementia of the Alzheimer's type.

To examine the role of semantic processes in the verbal priming deficits of patients with dementia of the Alzheimer type (DAT), 15 DAT patients, 8 amnesic patients, and 12 controls were administered a homophone spelling bias task. Ss' spellings were biased against their previously preferred homophone spellings by presenting the homophones aurally in a semantically related context. The results showed that DAT patients were not significantly different from controls or amnesic patients on the immediate priming measure. However, both patient groups' semantic priming effects decayed more rapidly and their recognition performance was significantly impaired in relation to those for control Ss. These results suggest that DAT patients can perform normally on some semantic priming tasks if the task demands are within the capacity of the patients' remaining intact semantic structure and if the delay between presentations is brief. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological deficits in patients with an anterior communicating artery syndrome: a multiple case study

The neuropsychological performance of five patients with an anterior communicating artery (ACoA) syndrome (amnesia, confabulation and personality changes) was studied. Neuroimaging techniques revealed a basal forebrain and frontal lobe pathology in all patients. The limbic system appeared intact. There was no evidence for an intellectual deterioration relative to the estimated premorbid IQ in four patients. Regarding attention, all patients showed significant deficits. Visuospatial disabilities could not be observed. On tests of executive functioning, all patients did exhibit severe problems. Every patient displayed a profound amnesic syndrome. A retrograde amnesia could be documented and was characterised by a temporal gradient. Short-term memory appeared normal. Concerning long-term memory, all patients scored out of the normal range on total immediate recall tasks. Four patients showed a normal recognition performance but produced a large number of false alarms. Despite a normal recognition performance, they were impaired in delayed recall tasks. However, one patient showed a full-blown amnesic syndrome, because his delayed recall and recognition of learned items were both depressed. Our results with regard to long-term memory functioning support the hypotheses which assume (1) the existence of recognition superiority and pathological false recognition, and (2) basal forebrain amnesia in ACoA patients.     

Memory and metamemory: A study of the feeling-of-knowing phenomenon in amnesic patients.

Tested accuracy of the feeling of knowing in 2 experiments, using 8 patients with Korsakoff's syndrome (mean age 54 yrs), 8 electroconvulsive shock therapy (ECT) patients (mean age 46.5 yrs), 4 Ss (mean age 47 yrs) with other causes of amnesia, 2 alcoholic control groups (7 Ss with a mean age of 47.6 yrs and 19 Ss with a mean age of 48.5 yrs), and 18 healthy controls (mean age 49 yrs). In Exp I, feeling-of-knowing accuracy for the answers to general information questions that could not be recalled was tested. Ss were asked to rank nonrecalled questions in terms of how likely they thought they would be to recognize the answers and were then given a recognition test for these items. Only Korsakoff's syndrome Ss were impaired in making feeling-of-knowing predictions. The other amnesic Ss were as accurate as control Ss in their feeling-of-knowing predictions. In Exp II, these findings were replicated in a sentence memory paradigm that tested newly learned information. Results show that impaired metamemory is not an obligatory feature of amnesia, because amnesia can occur without detectable metamemory deficits. The impaired metamemory exhibited by patients with Korsakoff's syndrome reflects a cognitive impairment that is not typically observed in other forms of amnesia. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterizing amnesic patients for neurobehavioral study.

One complicating feature of neuropsychological testing with amnesic patients is the fact that amnesic patients differ in terms of the pattern of their lesions and in terms of what damage is present in addition to the lesions that cause amnesia. Accordingly, as the questions asked of amnesic patients have become more sophisticated, it has become increasingly important in every group of study patients to obtain information about both the severity and the selectiveness of memory impairment. The suitability of several memory tests and other cognitive tests for the purpose of characterizing amnesic patients is considered. Data from these tests are presented for 10 amnesic patients (6 with Korsakoff's syndrome, 3 with amnesia owing to anoxia or ischemia, and case N.A.), who constitute our standing population of study patients, and for two control groups. Data from most of the tests are also presented for patients who were amnesic following bilateral electroconvulsive therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remote semantic memory in patients with Korsakoff's syndrome and herpes encephalitis.

Performance of patients with Korsakoff's syndrome and herpes encephalitis was compared on a retrograde amnesia (RA) test, asking subjects to recall and recognize the definitions of words that had come into the language at different time periods. Performance was also compared on a related test in which participants were asked to produce the words to definitions they were given in free recall and cued recall versions. It was hypothesized that, if the temporal gradient in remote memory results from a shift of information from episodic to semantic memory, then there should be a temporal gradient on these tasks, possibly steeper (i.e., greater relative sparing of early memories) in the patients in the Korsakoff group than in the herpes encephalitis group, who have widespread temporal lobe damage. Furthermore, in comparing semantic and episodic remote memory tests, consolidation theory would predict uniform temporal gradients across such tasks, whereas multiple trace theory would predict a differential pattern. The results showed that patients with Korsakoff's syndrome and patients with herpes encephalitis were significantly impaired across all time periods on the vocabulary tests, with only minimal evidence of temporal gradients, relative to healthy participants, and there was no evidence of a differential pattern of impairment between the two patient groups. Comparison with performance on measures of episodic retrograde amnesia, in which there was a differential pattern of temporal gradient, suggests that the relative preservation of early episodic remote memories in patients with Korsakoff's syndrome does not result from an episodic-to-semantic shift in the quality with which memories are stored. These findings are discussed in relation to existing theories of RA and to the patients' underlying patterns of neuropathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intermediate TCR cells can induce graft-versus-host disease after allogeneic bone marrow transplantation

In this study we compared memory performances of 29 probable patients with AD (17 mildly and 12 moderately demented) with those of 39 healthy young subjects, 36 elderly subjects (matched with the AD group for age and years of schooling), and 19 healthy very old subjects. In most of the memory tasks used in the present study, a progressive decline in performance was observed passing from the Young to the Elderly to the Very Old to the AD group. However, patients with AD were selectively impaired in the backward reproduction of verbal and spatial span sequences and in the semantic encoding of verbal material. These data are consistent with the hypothesis of not only quantitative but also a qualitative discontinuity between the process of normal aging and the dementia syndrome.     

Mammillary body and cerebellar shrinkage in chronic alcoholics: An MRI and neuropsychological study.

Mammillary body and cerebellar volume loss are common in Korsakoff's syndrome but are more controversial in chronic alcoholics without frank amnesia or ataxia. This study related magnetic resonance imaging (MRI) derived ratings of tissue volume reduction in the mammillary bodies, cerebellar hemispheres, and cerebellar vermis to tests of verbal and nonverbal long-term declarative memory and ataxia. Ss were 33 chronic alcoholic men and 20 healthy male controls. The alcoholics showed tissue shrinkage in all 3 brain regions compared with controls and were impaired on tests of balance but not memory. Memory scores did not correlate with mammillary body or cerebellar ratings, but the correlation between balance scores and cerebellar vermis ratings approached significance. The presence of significant mammillary body shrinkage in 48% of the nonamnesic alcoholics suggests that this tissue volume reduction alone is not sufficient to produce an amnesic syndrome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response Shifting and Inhibition, but Not Working Memory, Are Impaired After Long-Term Heavy Alcohol Consumption.

Chronic alcohol abuse leads to cognitive deficits. The authors investigated whether a systematic increase of interference in a 2-back working memory paradigm would lead to cognitive deficits in alcoholic participants and compared their performance in such a task with that in an alternate-response task. Twenty-four nonamnesic and nondemented alcohol abuse (AA) patients and 12 patients with Korsakoff's syndrome (KS) were compared with a control group. AA patients were impaired in the alternate-response task but not in working memory interference resolution. KS patients performed worse than the AA patients and the controls in both tasks. The neurotoxic side effects of alcohol therefore lead to a specific deficit in alternating between response rules but not in working memory, independently of whether the working memory task involves interference resolution or not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trace Eyeblink Conditioning in Abstinent Alcoholic Individuals: Effects of Complex Task Demands and Prior Conditioning.

Chronic misuse of alcohol affects an integrated neural circuit supporting the formation of associative memories acquired during eyeblink classical conditioning (R. McGlinchey-Berroth et al., 1995). The authors of this study investigated single-cue trace conditioning in amnesic and nonamnesic abstinent alcoholic individuals who either were or were not trained in a single-cue delay conditioning task. Overall, untrained alcoholic participants were severely impaired in acquisition, and alcoholic participants previously trained in single-cue delay conditioning performed similarly to untrained control participants. Individual performance in acquisition varied significantly within task but was relatively stable between the trace and delay tasks; there were nonamnesic and amnesic alcoholic participants who acquired responses at a normal rate in both delay and trace conditioning. The similarity of performances in delay and trace conditioning suggests a common source of impairment across both tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of spacing and repetition on amnesic patients' performance during perceptual identification, stem completin, and category exemplar production.

The effects of repetition and spacing of repetitions on amnesic patients' implicit task performance was studied. Amnesic patients and control participants performed a perceptual identification task, a word-stem completion task, and a category exemplar production task after the presentation of target words repeated within a list. Repetition proved to have no effect on perceptual identification or on word-stem completion, but it did play a role in category exemplar production. As expected, the amnesic patients demonstrated normal performance on the perceptual identification and word-stem completion tasks. However, on category exemplar production, the amnesic patients' performance was significantly below that of the control participants, and the 2 groups differentially responded to repetition. The normal control participants' spontaneous ability to analyze semantic features of words led to unconscious priming of the category and its links to the exemplars after only one presentation of a word. Amnesic patients. on the other hand, seemed to rely more on the fluency produced by multiple presentations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of a molecular clone of HIV type 2 infectious for Macaca nemestrina

The effects of repetition and spacing of repetitions on amnesic patients' implicit task performance was studied. Amnesic patients and control participants performed a perceptual identification task, a word-stem completion task, and a category exemplar production task after the presentation of target words repeated within a list. Repetition proved to have no effect on perceptual identification or on word-stem completion, but it did play a role in category exemplar production. As expected, the amnesic patients demonstrated normal performance on the perceptual identification and word-stem completion tasks. However, on category exemplar production, the amnesic patients' performance was significantly below that of the control participants, and the 2 groups differentially responded to repetition. The normal control participants' spontaneous ability to analyze semantic features of words led to unconscious priming of the category and its links to the exemplars after only one presentation of a word. Amnesic patients, on the other hand, seemed to rely more on the fluency produced by multiple presentations.     

Experience-dependent recovery of visuospatial functioning in older alcoholic persons.

Exposed 2 groups of alcoholic males to verbal and visuospatial paired-associate learning tasks known to be sensitive to alcohol dysfunction. Group 1, with 16 Ss (mean age 52.19 yrs), received 4 task administrations 3–4 days apart, beginning 4 days after drinking stopped. Group 2, with 14 Ss (mean age 49.79 yrs), received identical administration beginning 16 days after drinking stopped. An alternate form of the tasks was administered at the final session to assess transfer of training. Two matched nonalcoholic control groups of 12 Ss each (mean age 50.79 yrs) established normative performance on both forms of the tasks. Although the alcoholic Ss' verbal learning was unimpaired, visuospatial functioning was equally impaired initially in both alcoholic groups despite differing periods of abstinence, indicating the lack of time-dependent recovery. However, practice with the visuospatial task resulted in improved visuospatial performance and positive transfer of training not significantly different from normal Ss. It is suggested that since alcoholism treatment outcome is related to neuropsychological status, rehabilitation of cognitive functioning may improve treatment success. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sparing of semantic memory in Alzheimer's disease.

A number of investigators have suggested that unlike the normal elderly population, patients with Alzheimer's disease have a severe semantic-memory deficit. However, the semantic-memory tasks used in previous studies have been confounded by the heavy demands they placed on effortful processing. In the present study, 20 demented (mean age 71 yrs) and 20 normal (mean age 69.8 yrs) elderly Ss were given a battery of episodic-memory tasks and 3 tasks that examined how intact and accessible their semantic memory was under conditions that did not require effortful processing. Although the demented Ss were greatly inferior to the normal Ss on the episodic-memory tests, they performed equally well on the semantic-memory test: The naming latency of both groups was equally facilitated by a semantic prime, the recall accuracy of both normal and demented elderly for a string of letters was similarly affected by the degree to which the string approximated English orthography, and recall accuracy for a string of words was affected equally in the 2 groups by the degree to which the word string obeyed syntactic and semantic rules. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal and nonverbal fluency in patients with probable Alzheimer's disease.

Verbal fluency (semantic category naming and letter fluency) and nonverbal fluency (semantic category drawing and design fluency) were measured in mildly and moderately demented patients with probable dementia of the Alzheimer type (pDAT), and related to age at onset, disease duration, and disease severity. Group and individual patient analyses revealed impairments within verbal and nonverbal modalities that were most severe on semantic category fluency tasks. Detailed assessments of errors emphasized the role of compromised semantic memory in pDAT patients' impaired fluency, regardless of the modality of response. Fluency performance was related to dementia severity but not to age of onset or disease duration. It is concluded that deficits on measures of fluency in pDAT are due in large part to semantic memory impairments and that fluency may be useful for following disease progression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Jarrold et al. (2011).

Reports an error in "How does processing affect storage in working memory tasks? Evidence for both domain-general and domain-specific effects" by Christopher Jarrold, Helen Tam, Alan D. Baddeley and Caroline E. Harvey (Journal of Experimental Psychology: Learning, Memory, and Cognition, , , np). Chen and Cowan (2009) is correctly cited in the body of the article but the reference at the end of the article is incorrect. The correct reference is in the correction. (The following abstract of the original article appeared in record 2011-02787-001.) Two studies that examine whether the forgetting caused by the processing demands of working memory tasks is domain-general or domain-specific are presented. In each, separate groups of adult participants were asked to carry out either verbal or nonverbal operations on exactly the same processing materials while maintaining verbal storage items. The imposition of verbal processing tended to produce greater forgetting even though verbal processing operations took no longer to complete than did nonverbal processing operations. However, nonverbal processing did cause forgetting relative to baseline control conditions, and evidence from the timing of individuals' processing responses suggests that individuals in both processing groups slowed their responses in order to “refresh” the memoranda. Taken together the data suggest that processing has a domain-general effect on working memory performance by impeding refreshment of memoranda but can also cause effects that appear domain-specific and that result from either blocking of rehearsal or interference. (PsycINFO Database Record (c) 2011 APA, all rights reserved)