Metamemory monitoring and Parkinson's disease

Feeling-of-knowing (FOK) and global prediction in episodic memory were examined in 16 patients with Parkinson's disease (PD) and 16 elderly control subjects. Subjects were given cued recall and recognition tests of 20 critical cue-target words. Prior to the study phase, participants were asked to predict the number of words they could recall. During the recall phase, they judged their FOK for non-recalled words in terms of how likely they thought they would be able to recognize the key words on a subsequent recognition test. No difference was found in the two groups for global prediction accuracy. However in comparison to the older adults, PD patients exhibit impaired FOK accuracy, suggesting that in some circumstances metamemory may be altered in Parkinson's disease.     

Cognitive support at episodic encoding and retrieval: similar patterns of utilization in community-based samples of Alzheimer's disease and vascular dementia patients

The hypothesis that Alzheimer's disease (AD) and vascular dementia (VaD) differ in the pattern of episodic memory was examined in this study. Demented patients with AD and VaD and normal old adults were assessed on episodic memory tasks, including free recall and recognition of slowly and rapidly presented unrelated words and free and cued recall of organizable words. Results showed a general deficit in both demented groups across all memory variables, although the AD and VaD patients were indistinguishable across all measures. The normal old showed proficient utilization of more study time, organizability, and category cues. By contrast, the AD and VaD patients were able to benefit from cognitive support only when guidance was provided at both encoding and retrieval. In addition, in the normal old, recall of unrelated words was characterized by a relatively equal contribution from primary and secondary memory, whereas the demented patients relied predominantly on primary memory. The results suggests a similarity between AD and VaD patients with regard to the nature of the episodic memory impairment, despite etiologic differences between the diseases.     

Cognitive Support at Episodic Encoding and Retrieval: Similar Patterns of Utilization in Community-Based Samples of Alzheimer's Disease and Vascular Dementia Patients

The hypothesis that Alzheimer's disease (AD) and vascular dementia (VaD) differ in the pattern of episodic memory was examined in this study. Demented patients with AD and VaD and normal old adults were assessed on episodic memory tasks, including free recall and recognition of slowly and rapidly presented unrelated words and free and cued recall of organizable words. Results showed a general deficit in both demented groups across all memory variables, although the AD and VaD patients were indistinguishable across all measures. The normal old showed proficient utilization of more study time, organizability, and category cues. By contrast, the AD and VaD patients were able to benefit from cognitive support only when guidance was provided at both encoding and retrieval. In addition, in the normal old, recall of unrelated words was characterized by a relatively equal contribution from primary and secondary memory, whereas the demented patients relied predominantly on primary memory. The results suggests a similarity between AD and VaD patients with regard to the nature of the episodic memory impairment, despite etiologic differences between the diseases.     

A role for right medial prefontal cortex in accurate feeling-of-knowing judgements: evidence from patients with lesions to frontal cortex

The hypothesis that prefrontal cortex plays a critical role in accurate predictions of episodic memory performance was tested using the feeling-of-knowing (FOK) paradigm. Fourteen patients with a broad spectrum of damage to the frontal cortex and matched controls read sentences and later were tested for recall memory, confidence judgments, and FOK accuracy using as cues the sentences with the final word missing. While frontal patients were impaired at recall and recognition memory, they were able to make accurate confidence judgments about their recall attempts. By contrast, as a group, the patients were markedly impaired in the accuracy of their prospective FOK judgments. Lesion analysis of frontal patients with clear FOK impairment revealed an overlapping region of damage in right medial prefrontal cortex. These findings provide functional and anatomical evidence for a dissociation between recall confidence and prospective memory monitoring and are discussed in terms of familiarity and access theories of FOK predictions.     

帕金森病患者记忆监测与情景记忆的相关研究

目的 研究帕金森病患者( Parkinson's disease,PD)对情景记忆监测情况,并进一步探讨PD患者情景记忆障碍的可能机制.方法 建立情景记忆知晓感(feeling of knowing-episodic memory,FOK-EM)判断的试验范式,对25例PD患者和25名年龄及教育程度相匹配的健康对照(HC)者进行研究.结果 与HC组的FOK-EM的回忆率(39.67％±6.11％)、再认率(58.42％±7.50％)以及FOK判断准确率(0.61 ±0.22)比较,PD患者组FOK-EM的回忆率(19.33％±5.10％)、再认率(45.93％±7.82％)以及FOK判断准确率(-0.18±0.46)显著降低,差异均有统计学意义(t=-4.833,P＜0.01;t=-2.497,P＜0.05;t=-5.986,P＜0.01);FOK-EM的肯定判断/正确再认成绩(20.47％±10.78％)以及肯定判断/错误再认成绩(即高估,29.53％±5.62％)与HC组的肯定判断/正确再认成绩(39.47％±9.47％)以及肯定判断/错误再认成绩(即高估,13.90％±5.50％)之间差异有统计学意义(t =3.564,P＜0.05;t=2.306,P＜0.05),且Stroop效应与FOK-EM的肯定判断/错误再认成绩呈正相关(r =0.640,P＜0.01).结论 PD患者的情景记忆监测受损,表现为对自身再认能力的高估.这种记忆监测受损与执行功能的损害相关,提示此机制可能是导致PD患者情景记忆障碍的重要因素.     

Neuropsychological deficit in early subcortical vascular dementia: comparison to Alzheimer's disease

To further clarify the cognitive syndrome in subcortical vascular dementia (VaD), we investigated 20 patients with early-stage VaD as compared with 30 patients with Alzheimer's disease (AD) and 22 normal controls using episodic memory, attention/executive function and language tests. The patient groups were closely matched in terms of age, education and severity of dementia. The VaD patients had a significantly better free recall, cued recall and recognition memory than AD patients, the recognition being within normal limits in VaD. In addition, VaD patients had a greater number of perseverative errors during the Modified Card Sorting test, while AD patients exhibited more perseverations of semantic fluency. The results of retrieval deficit syndrome and increased number of perseverations during tasks sensitive to frontal lobe function are in agreement with the studies emphasizing the importance of frontal dysfunction in subcortical VaD. These findings are relevant for the early diagnosis of VaD and might be useful in the differential diagnosis with AD.     

Metamemory in Schizophrenia: an exploration of the feeling-of-knowing state

The ability to monitor memory performance has considerable importance in everyday life and is among the proposed metamemory dimensions which has been widely investigated. The ability to monitor memory performance accurately was examined in 16 patients with schizophrenia and 16 control subjects by using a Feeling-of-Knowing task on episodic information. Feeling-of-Knowing judgments are predictions made about the likelihood of subsequent recognition of currently non-recallable information. Participants were given cued recall and recognition tests of 50 sentence-target words. Feeling-of-knowing judgments were made for non-recalled targets. Our results first confirm that schizophrenia is associated with episodic memory impairment. By using the Feeling-of-Knowing task, patients with schizophrenia were found to predict accurately their subsequent recognition performance, suggesting an interesting dissociation between a preserved metamemory and an altered memory.     

Mechanisms underlying the production of false memories for famous people's names in aging and Alzheimer's disease

It is well known that the occurrence of false memories increases with aging, but the results remain inconsistent concerning Alzheimer's disease (AD). Moreover, the mechanisms underlying the production of false memories are still unclear. Using an experimental episodic memory test with material based on the names of famous people in a procedure derived from the DRM paradigm [Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory & Cognition, 21, 803–814], we examined correct and false recall and recognition in 30 young adults, 40 healthy older adults, and 30 patients with AD. Moreover, we evaluated the relationships between false memory performance, correct episodic memory performance, and a set of neuropsychological assessments evaluating the semantic memory and executive functions. The results clearly indicated that correct recall and recognition performance decreased with the subjects’ age, but it decreased even more with AD. In addition, semantically related false recalls and false recognitions increased with age but not with dementia. On the contrary, non-semantically related false recalls and false recognitions increased with AD. Finally, the regression analyses showed that executive functions mediated related false memories and episodic memory mediated related and unrelated false memories in aging. Moreover, executive functions predicted related and unrelated false memories in AD, and episodic and semantic memory predicted semantically related and unrelated false memories in AD. In conclusion, the results obtained are consistent with the current constructive models of memory suggesting that false memory creation depends on different cognitive functions and, consequently, that the impairments of these functions influence the production of false memories.     

The Category Cued Recall test in very mild Alzheimer's disease: discriminative validity and correlation with semantic memory functions

Episodic memory tests that measure cued recall may be particularly effective in the diagnosis of early Alzheimer's disease (AD) because they examine both episodic and semantic memory functions. The Category Cued Recall (CCR) test provides superordinate semantic cues at encoding and retrieval, and high discriminative validity has been claimed for this test. The aim of this study was to investigate the discriminative validity for this test when compared with the 10-word memory list from Alzheimer's Disease Assessment Scale (ADAS-cog) that measures free recall. The clinical diagnosis of AD was taken as the standard. It was also investigated whether the two episodic memory tests correlated with measures of semantic memory. The tests were administered to 35 patients with very mild AD (Mini Mental State Examination score > 22) and 28 control subjects. Both tests had high sensitivity (>88%) with high specificity (>89%). One out of the five semantic memory tests was significantly correlated to performances on CCR, whereas delayed recall on the ADAS-cog memory test was significantly correlated to two semantic tests. In conclusion, the discriminative validity of the CCR test and the ADAS-cog memory test was equivalent in very mild AD. This may be because CCR did not tap more semantic processes, which are impaired in the earliest phases of AD, than a test of free recall.     

Metamemory monitoring in mild cognitive impairment: Evidence of a less accurate episodic feeling-of-knowing

This study aimed at exploring metamemory and specifically the accuracy of memory monitoring in mild cognitive impairment (MCI) using an episodic memory feeling-of-knowing (FOK) procedure. To this end, 20 people with MCI and 20 matched control participants were compared on the episodic FOK task. Results showed that the MCI group made less accurate FOK predictions than the control group by overestimating their memory performance on a recognition task. The MCI overestimation behavior was found to be critically related to the severity of their cognitive decline. In the light of recent neuroanatomical models showing the involvement of a temporal-frontal network underlying accurate FOK predictions, the role of memory and executive processes was evaluated. Thus, participants were also administered memory and executive neuropsychological tests. Correlation analysis revealed a between-group differential pattern indicating that FOK accuracy was primarily related to memory abilities in people with MCI, whereas it was specifically related to executive functioning in control participants. The lesser ability of people with MCI to assess their memory status accurately on an episodic FOK task is discussed in relation to both their subjective memory complaints and to their actual memory deficits which might be mediated by the brain vulnerability of their hippocampus and medial temporal system. It is suggested that their memory weakness may lead people with MCI to use other less reliable forms of memory monitoring.     

Delayed recognition memory in Parkinson's disease: a role for working memory?

Immediate and delayed recognition memory for words was examined in a sample of 16 non-demented patients with Parkinson's disease and 16 normal control participants of equivalent age and educational attainment. The patients, relative to control participants, had intact immediate but impaired delayed recognition memory performance. Patients were also impaired on tests of free and cued recall, working memory and a measure of psychomotor processing speed. Processing speed was a significant covariate for delayed recognition, free and cued recall and working memory performance, but not for immediate recognition performance. These results suggest that the same cognitive processes which support performance on tests of recall and working memory also support performance on tests of delayed recognition.     

Episodic memory deficit in elderly adults with suspected delusional disorder

Herlitz A, Forsell Y. Episodic memory deficit in elderly adults with suspected delusional disorder. Acta Psychiatr Scand 1996: 93: 355–361. © Munksgaard 1996. This study examined memory functions in two groups of elderly adults with and without suspected delusional disorder (SDD). The samples consisted of 66 normal elderly subjects and 33 elderly subjects with symptoms, as reported by close informants, of delusional disorder. Subjects were matched with regard to age, gender and education, and there were no differences between the two groups with regard to performance of visuo-spatial and primary memory tasks. Subjects were examined concerning a variety of episodic recall and recognition tasks. The results demonstrated that subjects with SDD performed at a lower level than controls for some episodic memory tasks (i.e. recall tasks). There were no group differences in measures of episodic recognition or in the primary memory tasks. In addition, the group of subjects with SDD was, to the same extent as the control group, able to utilize cognitive support in the form of organization, cues and previous knowledge in order to enhance episodic memory. In summary, it appears that elderly adults with SDD have a mild episodic memory deficit in the absence of other cognitive deficits.     

抑郁症和早期阿尔茨海默病的记忆和执行功能

目的 研究抑郁症和早期阿尔茨海默病(AD)的神经心理学特征,试图运用神经心理学评估对两者进行鉴别。方法 对32例单相抑郁症、38例早期AD和34例对照进行WHO-UCLA词语学习、词语流畅、复杂图形和逻辑记忆的评估。结果 早期AD组神经心理学测验得分最低,抑郁症组次之,对照组最高,3组之间有显著性差异(P<0.01);抑郁症组仅表现为词语学习和逻辑记忆的自由回忆以及语义流畅的损害(P<0.05),而早期AD组表现为全面的认知功能损害(P<0.01);逐步判别分析提示,复杂图形延迟自由回忆、词语学习长时延迟自由回忆和语义流畅是区分抑郁症组和早期AD组的重要指标。结论 抑郁症和早期AD认知功能损害的特征不同,长时延迟自由回忆、再认和语义流畅能够区分早期AD和抑郁症。     

Routine clinical diagnosis of primary progressive non-fluent aphasia

It may be difficult to distinguish between a primary progressive aphasia at a very mild stage from the beginning of Alzheimer's disease (AD). However, this may be achieved by carrying out simple neuro-psychological tests. Nine non-fluent PPA (NFPPA) and 76 AD patients with comparable MMSE as well as 58 control subjects were evaluated using simple tests: MMSE, fluency, apraxia, naming, digital span, story memory, 5 words memory test. NFPPA patients had significantly impaired functions during the semantic category fluency and naming tests as compared to AD patients, whereas they showed a better delayed recall of the 5 words and story memory tests. As compared to AD, MMSE of NFPPA patients was also better in the time orientation and word recall sub-tests, although inferior in words repetition and language items. Thus, with comparable MMSE, NFPPA patients have more lexico-semantic difficulties, but a better delayed verbal memory than AD patients. These simple tests easily confirm the language impairment of NFPPA patients as opposed to the mnestic difficulties of AD, even at very early stages of these pathologies.     

The association between depressive and cognitive symptoms in amnestic mild cognitive impairment

BACKGROUND: Depressive symptoms are frequently observed in older adults with mild cognitive impairment (MCI). However, little is known regarding the cognitive characteristics of this important subgroup. METHODS: We examined executive functions (controlled inhibition) and verbal episodic memory in 33 healthy older adults (control group), 18 older adults with amnestic MCI plus subclinical depressive symptoms (a-MCI/D+ group), and 26 older adults with amnestic MCI but no depressive symptoms (a-MCI group). RESULTS: Compared to the a-MCI and control groups, patients with a-MCI/D+ showed poor controlled inhibition. Moreover, in verbal episodic memory these patients recalled fewer words than control participants on immediate free, delayed free, and delayed total (free plus cued) recall. Performance on immediate recall suggested a self-retrieval deficit, but delayed performance also revealed the existence of an encoding impairment. In the a-MCI group, participants exhibited normal performance on the executive task, but pervasive memory impairment; the memory deficit concerned free and total recall on both immediate and delayed tasks, suggesting the existence of encoding and self-retrieval disturbances. CONCLUSIONS: This study reveals differences between the pattern of cognitive impairment for a-MCI/D+ and a-MCI subgroups particularly at the level of executive capacities. In terms of memory functioning, the differences between the subgroups were more subtle; more studies are needed in order to better characterize the memory impairment of a-MCI/D+ and a-MCI patients.     

Brain regions associated with episodic retrieval in normal aging and Alzheimer's disease.

OBJECTIVE: To examine patterns of brain activation during verbal episodic retrieval in normal elderly subjects and patients in an early phase of AD. BACKGROUND: It is established that 1) a profound episodic memory impairment is a cardinal symptom of AD; and 2) some of the earliest brain changes in this disease occur in regions critical to episodic memory, such as the hippocampus and neighboring regions. Yet, it remains largely unknown whether the episodic memory deficit seen in AD is paralleled by concomitant alterations in brain activity during actual task performance in these or other brain areas. METHODS: Using PET, blood flow was assessed in normal elderly subjects and patients with early AD during two retrieval conditions involving completion of word stems: baseline and cued recall. RESULTS: The patients with AD showed a marked performance deficit in cued recall, although the two groups were indistinguishable in the baseline task condition. Both groups showed bilateral activity in orbital and dorsolateral prefrontal cortex, left precuneus, and right cerebellum, as well as decreased activity in distinct left temporal regions during cued recall. The normal elderly alone activated the left parietal cortex and the left hippocampal formation during episodic retrieval. By contrast, AD-related increases in activity during cued recall were observed in the left orbital prefrontal cortex and left cerebellum. CONCLUSIONS: The similar patterns of activations in the two groups suggest that a large distributed network involved in episodic memory retrieval functions relatively normally in early AD. Those retrieval activations seen in the normal elderly, as opposed to the patients, may reflect AD-related failures in semantic processing and successful recollection of the target information, respectively. Finally, the AD-related increases in activity were interpreted in terms of compensatory reactions to the difficulties in performing the episodic memory task.     

Further evidence on the effects of vitamin B12 and folate levels on episodic memory functioning: a population-based study of healthy very old adults.

BACKGROUND: The relationship between vitamin status and cognitive functioning has been addressed in several recent studies with inconclusive results. The purpose of this study was to examine separate and combined effects of serum vitamin B12 and folic acid on episodic memory functioning in very old age. METHODS: Four study groups were selected from a population-based sample of healthy very old adults (90-101 years of age): normal B12/normal folic acid, low B12/normal folic acid, normal B12/low folic acid, and low B12/low folic acid. Cutoff levels were set at 180 pmol/L for vitamin B12 and at 13 nmol/L for folic acid. Subjects completed two episodic recall tasks (objects and words) and two episodic recognition tasks (faces and words). RESULTS: Neither vitamin affected recognition or primary memory. Most interesting, although B12 was unrelated to recall performance, subjects with low folic acid levels showed impairment in both word recall and object recall. CONCLUSIONS: These results replicate and extend previous findings that folic acid may be more critical than B12 to memory functioning in late life. The selective effects of folic acid on episodic recall were discussed in terms of encoding and retrieval mechanisms, as well as in relation to brain protein synthesis.     

Verbal episodic memory in 426 multiple sclerosis patients: impairment in encoding, retrieval or both?

Episodic memory is frequently impaired in multiple sclerosis (MS) patients but the exact nature of the disorder is controversial. It was initially thought to be due to a retrieval deficit but some studies have demonstrated an encoding deficit, which could be linked to a slowing of information processing speed or to a deficit in elaboration of strategies. The main objective of this study is to assess the prevalence and the nature of verbal episodic memory (VEM) impairment in MS patients. We retrieved memory performances of 426 patients [314 F–112 M; mean age: 46.1 years; median Expanded Disability Status Scale (EDSS) score: 3.1] from a neuropsychological data base. VEM was assessed using the 16 words RL-RI 16 test. 66% MS patients present at least one recall impaired in VEM (37.2% from 2 to 5 recall). 14.2% MS patients present an impairment in encoding phase. We observed that 5% of patients presented recognition difficulties. Correlations were observed between VEM performances and EDSS, and disease duration but no group effect (ANOVA) is observed between form of MS and VEM performances. These results confirm the high prevalence of VEM impairment in MS patients. Deficits affect mainly information retrieval in early stage MS patients and are then linked to encoding as disability increases. Storage disorders are infrequent, so cognitive rehabilitation with mental imaging could be effective in MS patients.     

Intrusions in story recall: when over-learned information interferes with episodic memory recall. Evidence from Alzheimer's disease

Patients with Alzheimer's disease (AD) suffer from distortions of memory. Among such distortions, intrusions in memory tests are frequently observed. In this study we describe the performance of a group of mild AD patients and a group of normal controls on the recall of three different types of stories: a previously unknown story, a well-known fairy-tale (Cinderella), and a modified well-known fairy-tale (Little Red Riding Hood is not eaten by the wolf). The aim of our study was to test the hypothesis that in patients who tend to produce intrusions, over-learned information interferes with episodic recall, i.e., the retrieval of specific, unique past episodes. AD patients produced significantly more intrusions in the recall of the modified fairy-tale compared to the recall of the two other stories. Intrusions in the recall of the modified fairy-tale always consisted of elements of the original version of the story. We suggest that in AD patients intrusions may be traced back to the interference of strongly represented, over-learned information in episodic memory recall.