Differential rates of forgetting from long-term memory in Alzheimer's and multi-infarct dementia (original) (raw)
Related papers
1995
This study investigated the hypothesis that memory disordered patients suffer of an exalted forgetting rate from long-term memory within the first few minutes following acquisition. For this purpose, we administered to groups of Alzheimer's (AD), Multi-infarct demented (MID), pure amnesic and age-matched normal controls a test involving immediate and 15 min delayed word-list recall and a modified version of the Huppert and Piercy's procedure (1978) assessing yes/no Recognition for pictures at 90 sec, 10 min, 1 hr and 24 hr delay intervals. Results showed an abnormal immediate/delayed performance decline for the word list recall in AD and pure amnesic patients. In the same period, however, their Recognition score in the Huppert and Piercy's procedure decayed at normal rate. In the following intervals (1 hr and 24 hr), both groups disclosed abnormal forgetting slopes. Vascular demented patients, by contrast, disclosed fully normal forgetting rates both on the word-list recall and on the Huppert and Piercy's procedure. These findings are discussed in the light of cognitive mechanisms and neuroanatomical structures presumably underlying memory consolidation.
Verbal memory disorders in Alzheimer's disease and multi-infarct dementia
Journal of Neurolinguistics, 1989
On the basis of theoretical reasons, it could be predicted that Alzheimer's disease (AD) and Multi-infarct Dementia (MID) would provoke a different pattern of neuropsychological impairment, with a prevalent disruption of episodic memory in AD patients. This ending had not been obtained in previous investigations but this negative result could be due to the confounding effect of the greater severity of dementia usually observed in AD patients. The main purpose of the present research therefore consisted in comparing results obtained on various indices of verbal memory by two groups of AD and MID patients carefully matched as for the overall severity of dementia. With this aim in mind, a test of verbal memory (the Rey's 15 words memory test), allowing patients to obtain scores of immediate and delayed recall and of delayed recognition, was administend to 50 normal controls and to 41 AD and 35 MID patients, carefully matched as for the overall severity of dementia. Roth quantitative and qualitative differences were observed between the two diagnostic groups of dementia. From the quantitative point of view, AD patients scored significantly worse than MID patients on measures of immediate recall, delayed recall and delayed recognition. From the qualitative point of view, AD patients showed a severe disruption of the components of the serial position curve (primacy and central effects} reflecting the operations of the long-term memory system and a relative preservation of the component (recency effect) reflecting the functioning of the short-term memory system. Patients with MID, on the other hand, scored at a level of performance similar to that attained by normalcontrols in the first items of the curve, but then fell to a level similar to that shown by AD patients in the central and last components of the curve. This finding was interpreted as reflecting a decreased efficiency of the long-term memory system (and a correlative quick exhaustion of the attentional resources) of these patients. In the delayed recognition
Forgetting in Alzheimer's disease: Is it fast? Is it affected by repeated retrieval?
Neuropsychologia, 2020
Objectives: Whether people with Alzheimer's Disease present with accelerated long term forgetting compared to healthy controls is still debated. Typically, accelerated long term forgetting implies testing the same participants repeatedly over several delays. This testing method raises the issue of confounding repetition effects with forgetting rates. We used a novel procedure to disentangle the two effects. Methods: Four short stories were presented during an initial in-person assessment of 40 patients with Alzheimer's Disease and 42 age-matched healthy controls. Our aim was for participants to reach a score of 70% correct (9 out of 13 questions) at encoding. If this criterion was not achieved after the first trial, the four stories were presented again (in a different order); participants took the 1 min filler task again and were then retested. We repeated this process until participants reached the 70% criterion or to a maximum of four trials. Cued recall memory tests were completed during follow-up telephone call(s) at different delay intervals. Study material was presented only at encoding, then probed with different question sets on all other delays. Each question set tested different sub-parts of the material. The experiment employed a mixed design. Participants were randomly allocated to either a condition without retrieval practice or a condition with retrieval practice. Participants in the condition without retrieval practice were only tested at two delays: post encoding filled delay and at one month. Participants in the condition with retrieval practice were tested at four delays: post encoding filled delay, one day, one week and one month. Our methodological design allowed us to separate the effects of retesting from the effects of delay. Results: Alzheimer's Disease patients showed a significant encoding deficit reflected in the higher number of trials required to reach criterion. Using Linear Mixed Models, we found no group by delay interactions between the post encoding filled delay retrieval and one month delays, with Alzheimer's Disease groups having a similar decline in performance to healthy controls, irrespective of testing condition. Significant condition by delay interactions were found for both groups (Alzheimer's Disease and healthy controls), with better performance at one month in the condition with retrieval practice. Conclusions: Our data showed that Alzheimer's Disease is not characterised by accelerated long term forgetting, patients in our sample forgot at the same rate as healthy controls. Given the additional trials required by Alzheimer's patients to reach the 70% correct criterion, their memory impairment appears to be one of encoding. Moreover, Alzheimer's Disease patients benefited from repeated testing to the same extent as healthy controls. Due to our methodological design, we were also able to show that performance improved under repeated testing conditions, even with partial testing (sampling different features from each narrative on every test session/delay) in both healthy controls and Alzheimer's Disease. Abbreviations AD Alzheimer's disease HC Healthy controls MCI Mild cognitive impairment ALF Accelerated long-term forgetting MMSE Mini-Mental State Examination
Rates of forgetting in Alzheimer dementia
Neuropsychologia, 1998
Patients diagnosed with Alzheimer|s disease "AD# were compared with healthy controls on a picture recognition task\ a forced choice word recognition task\ a forced choice design recognition task\ a picture recall task and a stem completion task[ Performance on recognition and word stem completion was assessed at 0\ 09 and 19 min after exposure to experimental stimuli\ as these are delays across which previous studies had suggested there might be di}ering forgetting rates[ AD patients did not show signi_cantly faster rates of forgetting relative to controls on picture recognition\ design recognition\ word recognition or stem completion\ after levels of learning had been matched as closely as possible[ Moreover\ once initial learning was equated in a small number of subjects\ there were no qualitative di}erences between AD patients and controls following inclusion and exclusion instructions on the stem completion task[ In particular\ those AD patients who were matched to controls for initial levels of {{recollection|| showed comparable forgetting rates in recollection "or cued recall#[ Although matching was more di.cult for a picture recall task\ both the main analysis and subgroup analysis indicated faster forgetting in the AD group than controls\ suggesting a di}erence between {{free recall|| and recognition or cued recall measures\ comparable with the _nding in a parallel study of organic amnesia[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Verbal and spatial memory spans in Alzheimer's and multi-infarct dementia
Acta Neurologica Scandinavica, 2009
Aclii Neurol Scand 1994: BY. 132-138 Pritited in Bel@.iuniull rights reserved Copirigh 0 Muiil~gourd 1994 AClA NEUROLOGICA SCANDINXV1C.A I S S b 0001-6314 Verbal and spatial memory spans in Alzheimer's and multi-infarct dementia Carlesimo GA, Fadda L, Lorusso S, Caltagirone C. Verbal and spatial memory spans in Alzheimer's and multi-infarct dementia. Acta Neurol Scand 1994: 89: 132-138. 0 Munksgaard 1994. This study aimed to explore verbal and spatial memory spans in Alzheimer's (AD) and multi-infarct (MID) demented patients. For this purpose, we administered the forward and backward versions of the Digit Span and of the Corsi test to 18 AD, 18 MID and 26 controls. Results revealed a normal forward verbal span but reduced backward verbal and forward and backward spatial spans in both demented groups. These data are discussed in the light of the Working Memory model. It is argued that the normal verbal forward span is sustained by a normally functioning Articulatory Loop. The deficient processing resources of the Central Executive, on the other side, are responsible for the reduced extension of the other memory spans. The possible anatomical substrate of short-term memory impairment in dementia, as well as alternative interpretations of memory span performance in demented patients are discussed.
Processes of verbal memory failure in alzheimer-type dementia
Brain and Cognition, 1985
Multiple aspects of verbal learning and memory performance in mild as compared to moderate Alzheimer-type dementia (ATD) were studied with the Buschke selective reminding paradigm. Results show that (1) both groups of ATD subjects depend less on long-term memory (LTM) and more on short-term memory (STM) relative to elderly control subjects, (2) mild ATD subjects show less LTM encoding than moderate ATD subjects, (3) moderate ATD subjects retrieve a smaller portion of the items presumed to be encoded into LTM than do mild ATD subjects, and (4) high-imagery words increase LTM encoding and retrieval as compared to low-imagery words for moderate ATD subjects only. These results are explained by the inability of ATD subjects to attend to more than one component of the list-learning task, in conjunction with differences in the deployment of attention between mild and moderate ATD subjects. o 1985 Academic press, IIIC. Memory impairment is the most prominent aspect of the cognitive decline associated with mild to moderate Alzheimer-type dementia (ATD)
Patterns of Memory Performance in the Neurologically Impaired Aged
Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 1975
SUMMARY:The specific behavioral manifestation associated with the different disorders producing the syndrome of dementia have remained poorly investigated. We examined the memory performance of three distinct groups of patients with dementia secondary to Alzheimer's disease (AD) multiple-infarctions (MID) and vertebrobasilar insufficiency (VBI) on the ten subtests of the Wechsler Memory Scale (WMS). Statistical methods of analysis were used to maximize the differences between the groups. Univariate statistical procedures revealed that the AD group performed significantly and consistently lower than the two cerebrovascular groups. There were no significant differences between the two cerebrovascular disease groups, even though the MID group tended to perform consistently more poorly than the VBI group. For heuristic and conceptual purposes as well as to determine which combination of the ten WMS variables produced the “best” statistical model differentiating the groups the data w...
Memory improvement at different stages of Alzheimer's disease
Neuropsychologia, 1989
Three groups of patients with dementia of the Alzheimer type (mildly, moderately and severely demented) and two groups of healthy older adults (73 and 82 yr old) were examined on free and cued recall of subject-performed tasks (SPTs) or verbally presented sentences depicting the same verbal information as the SPTs. Results indicated that all groups examined performed better on SPTs than on the verbal task. In addition, for all groups cuing effects were greater in the SPT task than in the verbal task.