The origins of individual differences in memory among the elderly: A behavior genetic analysis.

Used behavior genetic methods to investigate individual differences in memory performance. Memory and various cognitive and lifestyle variables were obtained from 93 monozygotic twin pairs and 67 dyzygotic twin pairs (aged 60–88 yrs) as part of the Minnesota Twin Study of Adult Development and Aging. Univariate analysis, used to determine the relative influence of genetic and environmental factors on 4 measures of memory (word recall, immediate and delayed text recall, and figure memory), suggested that 55% of the variance in memory performance could be attributed to genetic factors. Bivariate analysis was used to determine the specific variables that mediate the genetic and environmental influences on memory. Results suggested that the relationship between memory and cognitive variables was genetic in nature, whereas the nature of the relationship between memory and lifestyle variables was environmental. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Material-specific memory in traumatic brain injury: Differential effects during acquisition, recall, and retention.

Material-specific memory refers to the ability to learn and recall new episodic information on the basis of the nature of the stimulus material (e.g., verbal vs. nonverbal-visuospatial). Structural equation modeling was used to analyze data from a sample of patients with traumatic brain injury to compare 3 models of memory functioning: material-specific, material-specific plus general, and general (non-material-specific). The models were examined separately for acquisition, delayed free recall, and retention aspects of memory. Results suggest that, at least in a population with traumatic brain injury, the acquisition of new information takes place in a material-specific memory fashion, delayed free recall involves both material-specific and general (non-material-specific) memory components, but retention relies primarily on general (non-material-specific) memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional limits in memory retrieval.

The hypothesis that episodic memory retrieval can occur in parallel with other cognitive processes was tested in 2 experiments. Participants memorized words and then performed speeded cued recall (Experiment 1) or speeded yes-no recognition (Experiment 2) in a dual-task situation. The psychological refractory period design was used: The participant was presented with a single test item at various stimulus onset asynchronies (SOAs; 50-1,000 ms) after a tone was presented in an auditory-manual 2-alternative choice reaction task. Reducing the SOA increased the memory task reaction times. This slowing was additive with the effect of variables slowing retrieval in the memory task. The results indicate that memory retrieval is delayed by central processes in the choice task, arguing that the central bottleneck responsible for dual-task interference encompasses memory retrieval as well as response selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetics of verbal working memory processes: A twin study of middle-aged men.

Genetic and environmental influences on cognitive components of reading span in 345 middle-aged male twin pairs were examined. Shared variance among word recognition (reading only), digits forward (short-term memory only), and reading span (concurrent reading plus memory) was almost entirely mediated by common genetic influences. Overall heritability was .52 for word recognition, .27 for digits forward, and .51 for reading span. All of the genetic influences on word recognition and digits forward, but only about one-half of the genetic influences on reading span, came from a common latent phenotype. The genetic influences that were specific to reading span were concluded to most likely reflect an executive function component. Implications for genetic studies of aging and prefrontal brain function are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Episodic memory functioning in a community-based sample of old adults with major depression: Utilization of cognitive support.

Community-based samples of old adults with current major depression (n?=?17; mean age 83.29 yrs) and healthy old adults (n?=?51; mean age 83.29 yrs) were examined on a variety of episodic recall and recognition tasks. Results indicate depression-related deficits in recall that were reduced but not eliminated, in recognition. Control Ss were able to utilize cognitive support in the form of more study time and item organizability in free recall, whereas depressed Ss were not. However, both groups showed equal gains from the provision of category cues and beneficial effects of prior knowledge and more study time in recognition. Results suggest that depression results in deficits in effortful, elaborate processes at encoding and retrieval and that old age depression is associated with a reduced ability to utilize cognitive support to improve episodic memory. Depressed older adults appear to require cognitive support at both encoding and retrieval to demonstrate memory facilitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval practice improves memory in multiple sclerosis: Clinical application of the testing effect.

The testing effect is a robust cognitive phenomenon by which memory retrieval on a test improves subsequent recall more than restudying. Also known as retrieval practice, the testing effect has been studied almost exclusively in healthy undergraduates. The current study investigated whether retrieval practice during testing leads to better delayed recall than restudy among persons with multiple sclerosis (MS), a neurologic disease associated with memory dysfunction. In a within-subjects design, 32 persons with MS and 16 demographically matched healthy controls (HC) studied 48 verbal paired associates (VPA) divided across 3 learning conditions: massed restudy (MR), spaced restudy (SR), and spaced testing (ST). Delayed VPA cued recall was measured after 45 min. There was a large main effect of learning condition (ηp2 = .54, p     

Deficient Strategic Control of Verbal Encoding and Retrieval in Individuals With Methamphetamine Dependence.

Methamphetamine (MA) dependence is associated with deficits in episodic verbal memory, but the cognitive mechanisms underlying such impairments are not known. The authors evaluated a component process model of episodic verbal memory in 87 persons with MA dependence (MA+) and 71 demographically similar non-MA-using controls (MA-). Compared with MA- controls, MA+ participants demonstrated deficient overall learning, free recall, and utilization of semantic clustering, as well as higher rates of repetitions and intrusions. No between-groups differences were evident on measures of serial clustering, retention, or recognition discrimination. Taken together, these findings indicate that MA dependence is associated with deficient strategic (i.e., executive) control of verbal encoding and retrieval, which is consistent with the sequelae of MA-related prefronto-striatal circuit neurotoxicity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory functioning in children and adolescents with autism.

Objective: Memory functioning in children and adolescents ages 5–19 with autism (n = 50) and typically developing controls (n = 36) was assessed using a clinical assessment battery, the Test of Memory and Learning (TOMAL). Method: Participant groups were statistically comparable in age, nonverbal IQ, handedness, and head circumference, and were administered the TOMAL. Results: Test performance on the TOMAL demonstrated broad differences in memory functioning in the autism group, across multiple task formats, including verbal and nonverbal, immediate and delayed, attention and concentration, sequential recall, free recall, associative recall, and multiple-trial learning memory. All index and nearly all subtest differences remained significant even after comparing a subset of the autism group (n = 36) and controls that were matched for verbal IQ (p > .05). However, retention of previously remembered information after a delay was similar in autism and controls. Conclusions: These findings indicate that performance on measures of episodic memory is broadly reduced in autism, and support the conclusion that information encoding and organization, possibly due to inefficient cognitive processing strategies, rather than storage and retrieval, are the primary factors that limit memory performance in autism. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A multinomial modeling analysis of the mnemonic benefits of bizarre imagery

A series of experiments was conducted to explore the cognitive processes that mediate the bizarreness effect, that is, the finding that bizarre or unusual imagery is recalled better than common imagery. In all experiments, subjects were presented with noun pairs that were embedded within bizarre or common sentences in a mixed-list design. None of the experiments produced a bizarreness effect for cued recall; however, for two of the experiments, the bizarre noun pairs were remembered significantly better than the common pairs for free recall. To determine if these differences were due to the storage or retrieval of the items, a multinomial model for the analysis of imagery mediation in paired-associate learning was developed and applied to the data from the experiments. The model revealed that bizarre sentences benefited the retrieval of the noun pairs but not their storage within memory. The empirical and modeling results are discussed relative to previous findings and theories on the bizarreness effect.     

The dynamics of memory retrieval in older adulthood.

One of the most robust findings in cognitive aging is that of a significant decline in self-initiated recall from episodic memory. In laboratory studies this deficit can be seen in significant age differences in word-list free recall. In this article, the authors focus on free recall of categorized word lists where one observes "response bursting" in the form of a rapid output of within-category items with longer delays between categories. Age differences appear primarily in between category latencies, results that are consistent with a relative sparing of semantic memory combined with an age-deficit in episodic retrieval. When adjusted for differences in overall mnemonic ability, it is demonstrated that the relationship between organization and learning remains invariant with normal aging. The authors argue that the locus of the age deficit in free recall lies at the level of temporal coding of items and the use of temporal associations to guide recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task-related and item-related brain processes of memory retrieval

In all cognitive tasks, general task-related processes operate throughout a given task on all items, whereas specific item-related processes operate differentially on individual items. In typical functional neuroimaging experiments, these two sets of processes have usually been confounded. Herein we report a combined positron emission tomography and event-related potential (ERP) experiment that was designed to distinguish between neural correlates of task-related and item-related processes of memory retrieval. Two retrieval tasks, episodic and semantic, were crossed with episodic (old/new) and semantic (living/nonliving) properties of individual items to yield evidence of regional brain activity associated with task-related processes, item-related processes, and their interaction. The results showed that episodic retrieval task was associated with increased blood flow in right prefrontal and posterior cingulate cortex, as well as with a sustained right-frontopolar-positive ERP, but that the semantic retrieval task was associated with left frontal and temporal lobe activity. Retrieval of old items was associated with increased blood flow in the left medial temporal lobe and with a brief late positive ERP component. The results provide converging hemodynamic and electrophysiological evidence for the distinction of task- and item-related processes, show that they map onto spatially and temporally distinct patterns of brain activity, and clarify the hemispheric encoding/retrieval asymmetry (HERA) model of prefrontal encoding and retrieval asymmetry.     

Substantial genetic influence on cognitive abilities in twins 80 or more years old

General and specific cognitive abilities were studied in intact Swedish same-sex twin pairs 80 or more years old for whom neither twin had major cognitive, sensory, or motor impairment. Resemblance for 110 identical twin pairs significantly exceeded resemblance for 130 fraternal same-sex twin pairs for all abilities. Maximum-likelihood model-fitting estimates of heritability were 62 percent for general cognitive ability, 55 percent for verbal ability, 32 percent for spatial ability, 62 percent for speed of processing, and 52 percent for memory. There was also evidence for the significant influence of idiosyncratic experience as the environmental component that most determines individual differences in cognitive abilities late in life.     

Transient global amnesia: implicit/explicit memory dissociation and PET assessment of brain perfusion and oxygen metabolism in the acute stage

OBJECTIVES: To assess explicit memory and two components of implicit memory--that is, perceptual-verbal skill learning and lexical-semantic priming effects--as well as resting cerebral blood flow (CBF) and oxygen metabolism (CMRO2) during the acute phase of transient global amnesia. METHODS: In a 59 year old woman, whose amnestic episode fulfilled all current criteria for transient global amnesia, a neuropsychological protocol was administered, including word learning, story recall, categorical fluency, mirror reading, and word stem completion tasks. PET was performed using the (15)O steady state inhalation method, while the patient still exhibited severe anterograde amnesia and was interleaved with the cognitive tests. RESULTS: There was a clear cut dissociation between impaired long term episodic memory and preserved implicit memory for its two components. Categorical fluency was significantly altered, suggesting word retrieval strategy--rather than semantic memory--impairment. The PET study disclosed a reduced CMRO2 with relatively or fully preserved CBF in the left prefrontotemporal cortex and lentiform nucleus, and the reverse pattern over the left occipital cortex. CONCLUSIONS: The PET alterations with patchy CBF-CMRO2 uncoupling would be compatible with a migraine-like phenomenon and indicate that the isolated assessment of perfusion in transient global amnesia may be misleading. The pattern of metabolic depression, with sparing of the hippocampal area, is one among the distinct patterns of brain dysfunction that underlie the (apparently) uniform clinical presentation of transient global amnesia. The finding of a left prefrontal hypometabolism in the face of impaired episodic memory and altered verbal fluency would fit present day concepts from PET activation studies about the role of this area in episodic and semantic memory encoding/retrieval. Likewise, the changes affecting the lenticular nucleus but sparing the caudate would be consistent with the normal performance in perceptual-verbal skill learning. Finally, unaltered lexical-semantic priming effects, despite left temporal cortex hypometabolism, suggest that these processes are subserved by a more distributed neocortical network.     

The influence of levels of processing on recall from working memory and delayed recall tasks.

Recent research in working memory has highlighted the similarities involved in retrieval from complex span tasks and episodic memory tasks, suggesting that these tasks are influenced by similar memory processes. In the present article, the authors manipulated the level of processing engaged when studying to-be-remembered words during a reading span task (Experiment 1) and an operation span task (Experiment 2) in order to assess the role of retrieval from secondary memory during complex span tasks. Immediate recall from both span tasks was greater for items studied under deep processing instructions compared with items studied under shallow processing instructions regardless of trial length. Recall was better for deep than for shallow levels of processing on delayed recall tests as well. These data are consistent with the primary-secondary memory framework, which suggests that to-be-remembered items are displaced from primary memory (i.e., the focus of attention) during the processing phases of complex span tasks and therefore must be retrieved from secondary memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Attention and verbal learning in patients with chronic fatigue syndrome

Former neuropsychological studies with Chronic Fatigue Syndrome (CFS) patients evaluated a broad range of cognitive functions. Several, but not all, reported subtle attentional and memory impairments suggesting possible mild cerebral involvement. In this study, a battery of attentional tests and a verbal memory task were administered to 20 CFS patients and 22 healthy controls (HC) in order to clarify the specific nature of attention and memory impairment in these patients. The results provide evidence for attentional dysfunction in patients with CFS as compared to HC. CFS patients performed more poorly on a span test measuring attentional capacity and working memory. Speeded attentional tasks with a more complex element of memory scanning and divided attention seem to be a sensitive measure of reduced attentional capacity in these patients. Focused attention, defined as the ability to attend to a single stimulus while ignoring irrelevant stimuli, appears not to be impaired. CFS patients were poorer on recall of verbal information across learning trials, and poor performance on delayed recall may be due to poor initial learning and not only to a retrieval failure.     

Long-term outcomes of memory retrieval under stress.

Previous studies have found impairing effects of stress hormones on memory retrieval. So far, it is unknown whether these impairments are temporary, persistent throughout time, or whether the strength of the memory trace changes after retrieval because of the effects of stress hormones on memory processes during retrieval. In the present study, delayed cued recall (6 months after initial learning) was compared between male participants who had retrieved previously learned word pairs during stress or a control condition. Retrieval (with or without stress) had taken place either 1 day or 5 weeks after initial encoding. The group that had retrieved words under stress 5 weeks after encoding performed worse on long-term recall than the comparable control group. However, when words were retrieved under stress 1 day after encoding, no long-term effect was found, although performance at 6 months in relation to performance under stress was slightly increased compared to the control group. These results support previous findings in animals that stress may affect memory during reactivation. It further suggests that time intervals between encoding and reactivation may play an important role. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mediators of long-term memory performance across the life span.

An individual-differences approach was used to examine the component processes that predict episodic long-term memory performance. A total of 301 participants ages 20-90 received a 7-hr cognitive battery across 3 days. Key constructs hypothesized to affect long-term memory function were assessed, including multiple measures of working memory and perceptual speed. Latent-construct, structural equation modeling was used to examine the relationship of these measures and age to different types of long-term memory tasks. Speed was a key construct for all 3 types of memory tasks, mediating substantial age-related variance; working memory was a fundamental construct for free and cued recall but not spatial memory. The data suggest that both speed and working memory are fundamental to explaining age-related changes in cognitive aging but that the relative contributions of these constructs vary as a function of the type of memory task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synergistic ecphory in recall and recognition.

Describes a general model of retrieval of episodic memory information, within which basic phenomena of recall and recognition can be integrated and related to commonly accepted theoretical ideas. The model also provides a statement of the relation between recall and recognition as 2 forms of retrieval: They are similar with respect to the process of ecphory, combining trace information and retrieval information into ecphoric information; they are different with respect to conversion of ecphoric information into recollective experience and memory performance. (French abstract) (52 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The semantic and episodic subcomponents of famous person knowledge: Dissociation in healthy subjects.

Fifty-two subjects between ages 40 and 79 years were administered a questionnaire assessing their ability to recall semantic information about famous people from 4 different decades and to recollect its episodic source of acquisition together with autonoetic consciousness via the remember-know paradigm. In addition, they underwent a battery of standardized neuropsychological tests to assess episodic and semantic memory and executive functions. The analyses of age reveal differences for the episodic source score but no differences between age groups for the semantic scores within each decade. Regardless of the age of people, the analyses also show that semantic memory subcomponents of the famous person test are highly associated with each other as well as with the source component. The recall of semantic information on the famous person test relies on participants' semantic abilities, whereas the recall of its episodic source depends on their executive functions. The present findings confirm the existence of an episodic-semantic distinction in knowledge about famous people. They provide further evidence that personal source and semantic information are at once distinct and highly interactive within the framework of remote memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual memory change after anterior temporal lobectomy: a base rate analysis using regression-based outcome methodology

PURPOSE: To characterize patterns of base rate change on measures of verbal and visual memory after anterior temporal lobectomy (ATL) using a newly developed regression-based outcome methodology that accounts for effects of practice and regression towards the mean, and to comment on the predictive utility of baseline memory measures on postoperative memory outcome. METHODS: Memory change was operationalized using regression-based change norms in a group of left (n = 53) and right (n = 48) ATL patients. All patients were administered tests of episodic verbal (prose recall, list learning) and visual (figure reproduction) memory, and semantic memory before and after ATL. RESULTS: ATL patients displayed a wide range of memory outcome across verbal and visual memory domains. Significant performance declines were noted for 25-50% of left ATL patients on verbal semantic and episodic memory tasks, while one-third of right ATL patients displayed significant declines in immediate and delayed episodic prose recall. Significant performance improvement was noted in an additional one-third of right ATL patients on delayed prose recall. Base rate change was similar between the two ATL groups across immediate and delayed visual memory. Approximately one-fourth of all patients displayed clinically meaningful losses on the visual memory task following surgery. Robust relationships between preoperative memory measures and nonstandardized change scores were attenuated or reversed using standardized memory outcome techniques. CONCLUSIONS: Our results demonstrated substantial group variability in memory outcome for ATL patients. These results extend previous research by incorporating known effects of practice and regression to the mean when addressing meaningful neuropsychological change following epilepsy surgery. Our findings also suggest that future neuropsychological outcome studies should take steps towards controlling for regression-to-the-mean before drawing predictive conclusions.