scholarly journals Associative and Implicit Memory Performance as a Function of Cognitive Reserve in Elderly Adults with and without Mild Cognitive Impairment

2016 ◽  
Vol 19 ◽  
Author(s):  
Salvador Algarabel ◽  
Alicia Sales ◽  
Alfonso Pitarque ◽  
Juan C. Meléndez ◽  
Joaquín Escudero ◽  
...  

AbstractThis study aims to analyze implicit and explicit memory performance as a function of cognitive reserve (CR) in a healthy control group (N = 39) and a mild cognitive impairment (MCI) group (N = 37). Both groups were subdivided into high and low cognitive reserve, and were asked to complete an explicit and implicit associative recognition tasks. The results showed that the control group was able to learn both tasks (η2 = .19, p < .0001), and the high CR group fared better (η2 = .06, p < .05). The MCI sample, conversely, was unable to learn the implicit relationship, and showed very little learning on the explicit association task. Participants diagnosed with MCI showed little plasticity in learning associations regardless of CR (η2 = .12, p < .01).

2019 ◽  
Author(s):  
KA Zhivago ◽  
Sneha Shashidhara ◽  
Ranjini Garani ◽  
Simran Purokayastha ◽  
Naren P. Rao ◽  
...  

ABSTRACTA decline in declarative or explicit memory has been extensively characterized in cognitive ageing and is a hallmark of cognitive impairments. However, whether and how implicit perceptual memory varies with ageing or cognitive impairment is unclear. Here, we compared implicit perceptual memory and explicit memory measures in three groups of subjects: (1) 59 healthy young volunteers (20-30 years); (2) 238 healthy old volunteers (50-90 years) and (3) 21 patients with mild cognitive impairment MCI (50-90 years). To measure explicit memory, subjects were tested on standard recognition and recall tasks. To measure implicit perceptual memory, we used a classic perceptual priming paradigm. Subjects had to report the shape of a visual search pop-out target. Implicit priming was measured as the speedup in response time for targets with the same vs different color/position on consecutive trials.Our main findings are as follows: (1) Explicit memory was weaker in old compared to young subjects, and in MCI compared to age-matched controls; (2) Surprisingly, implicit perceptual memory did not always decline with age: color priming was smaller in older subjects but position priming was larger; (3) Position priming was less frequent in the MCI group compared to age-matched controls; (4) Implicit and explicit memory measures were uncorrelated in all three groups. Thus, implicit memory can increase or decrease with age or cognitive impairment, but this decline does not covary with explicit memory. We propose that incorporating explicit and implicit measures can yield a richer characterization of memory.


2018 ◽  
Vol 10 (3) ◽  
pp. 40 ◽  
Author(s):  
Richard E. Hicks ◽  
Victoria E. Alexander ◽  
Mark Bahr

How our memory is affected as we age has been given considerable attention over recent decades as we strive to understand the cognitive processes involved. Memory types have been identified as either explicit (declarative - related to episodes or semantics) or implicit (non-declarative – related to procedures, habits, or earlier priming). Studies have identified likely age-related decline in explicit but not implicit memory though there are opposing results suggested from other studies. It is thought cognitive reserve capacities might explain any non-decline as aging individuals use alternative or additional pathways to ‘remember’. This theory might be supported indirectly if older members remember material accurately but take longer to supply answers. In our current study we re-examined whether age-related differences in accuracy and speed of access in memory are present in both implicit and explicit memory processes and we increased the number of experimental age groups (from 2 to 3) - most previous studies have compared just two groups (young, and old). With three groups (young, middle-old, and older aged groups) we can identify trends across the age range towards deterioration or preservation of memory. We examined sixty-six participants (49 females; 17 males) aged 18 to 86 years (M = 50.27, SD = 21.06) from South-Eastern Queensland and divided these into younger (18 to 46 years of age), middle old (50 to 64) and older aged (65+) cohorts. Participants were administered tasks assessing implicit and explicit memory using computer presentations. Consistent with most prior research, no age differences were identified on accuracy in the implicit memory tasks (verbal and non-verbal, including priming), suggesting that memory for implicit material remains preserved. However, on the explicit memory tasks, older adults performed less accurately than the younger adults, indicative of decline in explicit memory as we age. The finding of a decline in explicit memory but no significant decline in implicit memory confirms most earlier research and is consistent with a view of modular decline rather than overall decline in memory with increasing age. In addition, differences found in speed of response in otherwise accurate implicit memory with older respondents significantly slower, suggests possible support for the cognitive reserve hypothesis. 


1996 ◽  
Vol 2 (2) ◽  
pp. 111-125 ◽  
Author(s):  
Maureen Schmitter-Edgecombe

AbstractThis study explored the nature of the relationship between attention available at learning and subsequent implicit and explicit memory performance. One hundred neurologically normal subjects rated their liking of target words on a five-point scale. Half of the subjects completed the word-rating task in a full attention condition and the other half performed the task in a divided attention condition. Following administration of the word-rating task, all subjects completed five memory tests, three implicit (category association, tachistoscopic identification, and perceptual clarification) and two explicit (semantic-cued recall and graphemic-cucd recall), each bearing on a different subset of the list of previously presented target words. The results revealed that subjects in the divided attention condition performed significantly more poorly than subjects in the full attention condition on the explicit memory measures. In contrast, there were no significant group differences in performance on the implicit memory measures. These findings suggest that the attention to an episode that is necessary to produce later explicit memory may differ from that necessary to produce unconscious influences. The relationship between implicit memory, neurologic injury, and automatic processes is discussed. (JINS, 1996, 2, 111–125.)


2006 ◽  
Vol 105 (5) ◽  
pp. 920-926 ◽  
Author(s):  
Christopher A. Stonell ◽  
Kate Leslie ◽  
Cheng He ◽  
Leonard Lee

Background Women respond differently to anesthesia than men, initially recovering more rapidly, but having more postoperative morbidity. Studies on surgical patients report evidence of memory formation during anesthesia. However, sex differences in memory formation have not been explored. Therefore, the authors investigated sex differences in the implicit and explicit memory formation during general anesthesia. Methods With ethics committee approval, 120 consenting adult patients scheduled to undergo surgery during general anesthesia were recruited. Intraoperatively, 16 target words were presented to patients via headphones, and the Bispectral Index was recorded. Postoperatively, memory for presented words was tested using a word stem completion test. The test was divided into inclusion and exclusion parts, to delineate implicit and explicit memory contributions. Results Target and distracter hit rates were similar in men and women. For the whole study group, there was a significant difference between inclusion target hit rate (0.42) and base hit rate (0.39) (P = 0.01). Buchner's model suggested that this memory formation was attributable to both implicit and explicit memory. A Bispectral Index value greater than 50 was the only significant predictor of inclusion target hit rate. None of the patients were able to consciously recall the words presented during surgery. Conclusions Patients showed greater memory performance for words presented during general anesthesia than for words not presented. However, sex differences in memory formation were not observed. A relation between hypnotic state and memory during sevoflurane anesthesia was also established, suggesting that memory formation is possible even at hypnotic depths considered to be adequate anesthesia.


2020 ◽  
Vol 17 (2) ◽  
pp. 158-167
Author(s):  
Olga Gelonch ◽  
Neus Cano ◽  
Marta Vancells ◽  
Marc Bolaños ◽  
Laia Farràs-Permanyer ◽  
...  

Background: Individuals with amnestic Mild Cognitive Impairment (aMCI) are at heightened risk of developing Alzheimer's dementia. In recent years, much attention has been given to the search for new interventions to slow down the progression of cognitive decline of these patients. Wearable digital camera devices are one form of new technology that captures images of one’s life events, so they constitute a promising method to be used as a means to stimulate recent autobiographical memory. Objective: This preliminary study investigates the ability of a new cognitive intervention based on exposure to recent autobiographical memory captured by wearable cameras to improve episodic memory in patients with aMCI. Method: Seventeen subjects wore a wearable camera while they went about their daily activities. The images captured were converted into eight different 3-minute films containing the most relevant information of each event. The intervention involved eight individualized weekly sessions during which patients were exposed to a different autobiographical event each week. Besides, several specific questions were formulated within each session. Clinical questionnaires assessing cognitive reserve, premorbid intelligence, depression, and anxiety were administered at baseline. Measures of objective episodic memory were applied at baseline and at post-treatment. Results: Significant improvements were observed at post-treatment in memory measures, and significant associations were found between memory change scores and age and cognitive reserve. Anyway, these associations did not reach statistical significance after adjusting for multiple comparisons. Conclusion: The present study provides preliminary evidence that aMCI patients may benefit from a cognitive intervention program based on re-experiencing recent autobiographical events. However, future studies incorporating a control group will be needed to confirm these preliminary findings.


2000 ◽  
Vol 93 (6) ◽  
pp. 1418-1425 ◽  
Author(s):  
Clare L. Stapleton ◽  
Jackie Andrade

Background Many studies have shown that patients may remember words learned during apparently adequate anesthesia. Performance on memory tests may be influenced by explicit and implicit memory. We used the process dissociation procedure to estimate implicit and explicit memory for words presented during sedation or anesthesia. Methods We investigated intraoperative learning in 72 women undergoing pervaginal oocyte collection during propofol and alfentanil infusion. One word list was played once before infusion, another was played 10 times during surgery. Venous blood was taken for propofol assay at the end of the intraoperative list. Behavioral measures of anesthetic depth (eyelash reflex, hand squeeze response to command) were recorded and used to adjust the dose of anesthetic where clinically appropriate. On recovery, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions. Results The mean blood propofol concentration was 2.5 microg/ml (median, 2.3 microg/ml; range, 0.7-6.1 microg/ml). Mean alfentanil dose was 2.1 mg (median, 2.0 mg; range, 1.2-3.4 mg). Comparison of target and distractor hits in the inclusion condition showed memory for preoperative words only. However, the process dissociation procedure estimates showed explicit (mean, 0.18; P &lt; 0.001) and implicit (mean, 0.05; P &lt; 0.05) memory for the preoperative words, and a small amount of explicit memory for the intraoperative words (mean, 0.06; 95% confidence interval, 0.01-0.10). Memory performance did not differ between the 17 patients who consistently responded to command and eyelash reflex and the 32 patients who remained unresponsive. Blood propofol concentration and alfentanil dose did not correlate with memory for the intraoperative list. Conclusions There was no unprompted recall of surgery, but the process dissociation procedure showed memory for words presented during surgery. This memory was apparently explicit but did not correlate with the measures of depth of anesthesia used.


Author(s):  
Juan C. Meléndez ◽  
Alfonso Pitarque ◽  
Iraida Delhom ◽  
Elena Real ◽  
Mireia Abella ◽  
...  

Background: The main objective of this study was to analyze the evolution of autobiographical memory (both episodic and semantic) in patients with mild cognitive impairment, patients with Alzheimer’s disease, and a healthy control group. We compared these groups at two time points: first, at baseline, and in a follow-up after 18 months. Method: Twenty-six healthy older adults, 17 patients with mild amnestic cognitive impairment, and 16 patients with Alzheimer’s disease, matched on age and educational level, were evaluated at both time points with the Autobiographical Memory Interview. Results: The results showed significant longitudinal deterioration in episodic and semantic autobiographical memory in patients with mild cognitive impairment and in patients with Alzheimer’s disease, but not in healthy older adults. Conclusions: The deterioration of episodic and semantic autobiographical memory in AD is confirmed; however, although the episodic was impaired in aMCI, a pattern that evolved toward deterioration over a period of eighteen months was observed for the semantic autobiographical memory.


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