Prospective memory: A neuropsychological study.

To examine the neuropsychology of prospective remembering, older adults were divided preexperimentally into 4 groups on the basis of their scores on 2 composite measures: one assessing frontal lobe function and the other assessing medial temporal lobe function. The groups reflected the factorial combination of high and low functioning for each neuropsychological system, and they were tested on an event-based laboratory prospective memory task. High-functioning frontal participants showed better prospective remembering than low-functioning frontal participants. There was no significant difference in prospective memory performance attributable to medial temporal functioning. The results support the theoretical notion that frontal lobe processes play a key role in prospective remembering. Discussion focuses on the particular components of prospective memory performance that frontal lobes might mediate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do young and older adults rely on different processes in source memory tasks? A neuropsychological study.

Source memory has consistently been associated with prefrontal function in both normal and clinical populations. Nevertheless, the exact contribution of this brain region to source memory remains uncertain, and evidence suggests that processes used by young and older adults may differ. The authors explored the extent to which scores on composite measures of neuropsychological tests of frontal and medial temporal function differentially predicted the performance of young and older adults on source memory tasks. Results indicated that a frontal composite measure, consistently associated with source memory performance in older adults, was unrelated to source memory in young adults, although it was sensitive to a demanding working memory task. The memory composite score, however, predicted performance in the young group. In addition, item and source memory were correlated in young but not older people. Findings are discussed in terms of age-related differences in working memory and executive functions, and differential binding processes necessary for item and source memory. The requirement to integrate item and source information at encoding appears to place greater demands on executive or working memory processes in older adults than in younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A meta-analytic review of the sensitivity of the Wisconsin Card Sorting Test to frontal and lateralized frontal brain damage.

The author conducted 2 meta-analyses on the Wisconsin Card Sorting Test (WCST). The 1st compared participants with frontal lobe damage to those with posterior brain damage, whereas the 2nd compared participants with left and right frontal damage. Effect sizes based on the difference between groups were calculated for WCST variables and a composite measure. Effect sizes for these variables, except nonperseverative errors, indicated significantly poorer performance for participants with frontal damage. There were no significant differences for the left versus right comparisons. Moderator analyses using the composite measure for the frontal versus nonfrontal analyses indicated that the largest effect size was for dorsolateral damage. Though this study indicates that the WCST is sensitive to frontal lobe damage, caveats are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contribution of Frontal and Temporal Lobe Function to Memory Interference From Divided Attention at Retrieval.

On the basis of their scores on composite measures of frontal and temporal lobe function, derived from neuropsychological testing, seniors were divided preexperimentally into 4 groups. Participants studied a list of unrelated words under full attention and recalled them while concurrently performing an animacy decision task to words, an odd-digit identification task to numbers, or no distracting task. Large interference effects on memory were produced by the animacy but not by the odd-digit distracting task, and this pattern was not influenced by level of frontal or temporal lobe function. Results show associative retrieval is largely disrupted by competition for common representations, and it is not affected by a reduction in general processing resources, attentional capacity, or competition for memory structures in the temporal lobe. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact perceptual and conceptual priming in temporal lobe epilepsy: Neuroanatomical and methodological implications.

Explicit memory appears to be supported by medical temporal lobe structures, whereas separate neocortical regions may mediate perceptual and conceptual implicit memory. Children and adults with temporal lobe epilepsy (TLE) and matched controls were administered experimental verbal memory tests. Performance on implicit tests--word identification and word generation--was contrasted with explicit recognition and recall. Encoding conditions emphasized either conceptual or perceptual aspects of study words and were crossed with presentation modality. The priming performance of participants with TLE did not differ from controls, but participants with TLE did show deficits on recognition and recall measures. Thus, intact left temporal cortex does not appear to be necessary for normal implicit memory performance, even when conceptual processing is emphasized at study or test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency judgements of abstract designs by patients with diencephalic, temporal lobe or frontal lobe lesions

Patients with diencephalic, temporal lobe or frontal lobe lesions were compared with healthy controls on a frequency judgement task. The three patient groups were disproportionately impaired at estimating how often a series of abstract designs had been presented relative to controls. Diencephalic and temporal lobe patients did not differ from each other. It is argued that the results may reflect a 'core' memory deficit in the temporal lobe patients. The impairment in the frontal patients may reflect their difficulty in making an organised search in memory for multiple traces of an item, while the deficit shown by the diencephalic patients (particularly those with Korsakoff syndrome) may be due to the combined effects of a generally poor memory and superimposed frontal pathology.     

Aging, episodic memory feeling-of-knowing, and frontal functioning.

Groups of normal old and young adults made episodic memory feeling-of-knowing (FOK) judgments and took 2 types of episodic memory tests (cued recall and recognition). Neuropsychological tests of executive and memory functions thought to respectively involve the frontal and medial temporal structures were also administered. Age differences were observed on the episodic memory measures and on all neuropsychological tests. Compared with young adults, older adults performed at chance level on FOK accuracy judgments. Partial correlations indicated that a composite measure of frontal functioning and FOK accuracy were closely related. Hierarchical regression analyses showed that the composite frontal functioning score accounted for a large proportion of the age-related variance in FOK accuracy. This finding supports the idea that the age-related decline in episodic memory FOK accuracy is mainly the result of executive or frontal limitations associated with aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deterioration of frontal lobe function in normal aging: Influences of fluid intelligence versus perceptual speed.

A group of young participants were compared with 2 groups of older participants (young-old, 65–74 years and old-old, 75 years or over) on a range of frontal lobe tasks. They were also assessed on the Digit Symbol Substitution Test (DSST), a test of digit cancellation (DC), the AH4 test of fluid intelligence, and the National Adult Reading Test (NART)—a measure of crystalized intelligence. Reliable age differences on all frontal measures except word fluency (FAS) were found. However, age effects were radically attenuated when either DSST speed or Alice Heim 4 (AH4) performance was used as a covariate. In contrast, DC and NART attenuated age-related variance to a much lesser degree. The authors conclude that a large proportion of age-related variance on measures of frontal lobe function may be attributed to a more general factor characterized jointly by DSST and AH4 performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-task performance in dysexecutive and nondysexecutive patients with a frontal lesion.

Patients with defined frontal lobe lesions were assigned to 1 of 2 groups based on whether they showed a behaviorally assessed dysexecutive syndrome or were behaviorally normal. All participants were tested on dual-task performance and on 2 tasks assumed to measure frontal lobe function, the Wisconsin Card Sorting Test and verbal fluency. The dysexecutive group differed significantly from the nondysexecutive in showing impaired capacity for dual-task coordination, but there were no significant differences on the Wisconsin Card Sorting Test and verbal fluency. Results are interpreted in terms of a multicomponent central executive, whose function is linked to, but not coterminous with, the operation of the frontal lobes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory interference effects and aging: Findings from a test of frontal lobe function.

Performance on behavioral measures of self-ordered pointing and 2-choice recognition memory was evaluated in young adults (aged 18–23 yrs) and 2 groups of older adults (aged 61–70 yrs and 71–80 yrs). The self-ordered pointing test involves working memory and has been used as an index of frontal lobe dysfunction; to perform well, Ss must organize stimulus information and monitor responses. Both groups of older adults exhibited impairment on the pointing test, but the pattern of impairment was different for the 2 groups. Individuals in their 60s exhibited impairment on a 2nd block of trials but not on the 1st block. Individuals in their 70s exhibited deficits on both blocks of trials. On the recognition test, only individuals in their 70s exhibited impairment. The findings suggest that age-related impairments occur in both working memory and recognition memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for intact semantic representations in patients with frontal lobe lesions.

Patients with frontal lobe lesions and control participants were assessed on 2 tests of semantic knowledge. In the triadic comparison task, participants were shown all possible triplets of 12 animal names and judged which 2 of each triplet were most alike. In the ordered similarity task, participants rank ordered animals in terms of their similarity to a target animal. For both tasks, semantic structure-- derived from multidimensional scaling techniques-- revealed similar representations in patients with frontal lobe lesions and control participants. Additional pathfinder analyses also produced networks that did not differ between groups. These patients exhibited intact semantic knowledge despite deficits on tests of free recall and verbal fluency that involved the same semantic category and exemplars. Thus, intact representation of semantic knowledge in frontal patients stands in contrast to their marked deficits in strategic retrieval of semantic knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and flexible remembering: Contributions of conceptual span, fluid intelligence, and frontal functioning.

Aging attenuates the capacity to adaptively and flexibly use episodic memory at different levels of specificity. Older and younger adults were tested on a picture recognition task that required them to make episodic memory decisions at an item-specific (verbatim) versus category-based (gist-based) level on randomly intermixed trials. Specificity modulation was assessed using a measure of the likelihood that participants retrieved verbatim information in order to reject test items that were categorically related to studied items under item-specific recognition instructions (recollection rejection). We found that this measure positively correlated with conceptual span (an index of short-term semantic memory) and with level of fluid intelligence in older and younger adults. However, when we simultaneously considered each of four possible contributors (age, conceptual span, fluid intelligence, and frontal function), the only significant predictor of recollection rejection was the composite fluid intelligence measure (assessed by the Culture Fair Intelligence Test [Cattell & Cattell, 1960] and the Wechsler Adult Intelligence Scale—Revised Block Design subtest [Wechsler, 1981]). These findings suggest that interventions that facilitate adaptive specificity modulation in episodic memory may enhance the flexibility of thinking, and vice versa, in both older and younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical priming deficits as a function of age.

The effects of age on implicit memory were assessed in elderly and young adults using 2 priming procedures. Subjects also completed the Wechsler Adult Intelligence Scale—Revised (WAIS—R), 3 tests to assess frontal lobe function, and 2 recall and 2 recognition tests of explicit memory. In Experiment 1, subjects were exposed to the low-frequency member of a homophone pair in a test purported to assess general knowledge. Subsequently, subjects completed a spelling test that contained the previously presented homophones to assess priming. Young subjects demonstrated priming (p?p?p?     

Comparison of older people and patients with frontal lesions: Evidence from word list learning.

We examined the hypothesis that changes in memory performance of older normal participants are due to frontal lobe dysfunction by comparing three groups of normal individuals (young, middle-aged, and older) with three groups of patients who had documented lesions in specific frontal regions: unilateral right, unilateral left, and bilateral. All participants were given 4 successive learning trials on each of 3 lists of words: unrelated, related but presented in a pseudo-random order, and related and presented in a blocked format. We found significant correspondences in performance between the older normal participants and the (younger) frontal damaged groups. The qualitative nature of recall performance, particularly as measured by indices of organizational control processes, was similar between older normals and patients with frontal damage, particularly those with right frontal damage, but different from that normally exhibited by patients with focal limbic/memory dysfunction. These results add to the evidence that at least some of the decline in older people in tasks which measure executive or supervisory abilities is due to frontal system dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationships between normal aging, frontal lobe function, and memory for temporal and spatial information.

Young and old participants were evaluated on tests of frontal lobe function, recognition memory, and memory for temporal and spatial information. Older participants showed significant impairments on memory for temporal order, and this impairment was found to correlate with deficits on frontal lobe tests measuring spontaneous flexibility but not reactive flexibility. However, spatial memory showed no evidence of an age effect. An interpretation of this latter finding based on the differential availability of contextual cues is ruled out because similar results were obtained when spatial memory was assessed in a different context to that used during learning. The researchers concluded that memory for temporal order and spatial memory are affected differentially by age. Theoretical interpretations of this difference are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of the frontal lobe functioning hypothesis of age deficits in production priming.

Older adults have been hypothesized to show reduced priming relative to younger adults on implicit memory tests that require production of a response because these tasks place high demands on attentional processes associated with frontal lobe function, which are often reduced with age (see D. A. Fleischman & J. D. E. Gabrieli, 1998). The current study directly tested this frontal lobe hypothesis of age effects in production priming. Younger adults and older adults who differed in their attentional abilities as measured by a battery of neuropsychological tests were given two production priming tasks, word stem completion and category production, followed by explicit free recall tests. Results showed that explicit memory performance was reduced by age and older adults' frontal functioning. Age and frontal functioning influenced category production priming but not word stem completion priming. Results failed to support the frontal account of age reductions in production priming. Instead, results implicate the influence of other processes often involved in production priming tasks, such as explicit memory strategies and response competition, as critical for understanding age effects in implicit memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relations between source amnesia and frontal lobe functioning in older adults.

A study is reported in which the relations among normal aging, source amnesia, and frontal lobe functioning were explored. Twenty-four older adults (aged 60–84 years) were tested on their ability to remember where they had acquired new factual information; they were also given the Wisconsin Card Sorting Test (WCST), a test of verbal fluency, and other psychometric tests. The degree of source amnesia in this normal sample correlated with age, verbal fluency, and some measures from the WCST. Source amnesia was not related to Performance IQ, however, or to a measure of fact recall. The implications for the relations among aging, memory, and frontal lobe functions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Explicit and implicit memory in the elderly: Evidence for double dissociation involving medial temporal- and frontal-lobe functions.

Groups of normal old people living in institutions or in the community and young adults were administered tests of implicit (IM) and explicit (EM) memory with word-stem (WSC) and word-fragment (WFC) completion paradigms. Neuropsychological tests sensitive to frontal and medial temporal lobe function were also administered. Age differences were observed on both tests of EM and on all neuropsychological tests. Priming effects on WSC were smaller in the institutionalized group than the other 2 groups. Comparisons of EM and IM test results with neuropsychological test scores revealed several effects, including significant correlations (a) between EM scores on both tests and performance on standard memory tests in both aged groups and (b) between IM scores of both aged groups on WSC and frontal-lobe test performance. The results provide evidence of a double dissociation with respect to involvement of brain regions in EM and IM. They also indicate that repetition priming in WSC and WFC involve different mechanisms and that frontal-lobe dysfunction is a factor in reduced priming on the WSC test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Musical expertise, bilingualism, and executive functioning.

The authors investigated whether intensive musical experience leads to enhancements in executive processing, as has been shown for bilingualism. Young adults who were bilinguals, musical performers (instrumentalists or vocalists), or neither completed 3 cognitive measures and 2 executive function tasks based on conflict. Both executive function tasks included control conditions that assessed performance in the absence of conflict. All participants performed equivalently for the cognitive measures and the control conditions of the executive function tasks, but performance diverged in the conflict conditions. In a version of the Simon task involving spatial conflict between a target cue and its position, bilinguals and musicians outperformed monolinguals, replicating earlier research with bilinguals. In a version of the Stroop task involving auditory and linguistic conflict between a word and its pitch, the musicians performed better than the other participants. Instrumentalists and vocalists did not differ on any measure. Results demonstrate that extended musical experience enhances executive control on a nonverbal spatial task, as previously shown for bilingualism, but also enhances control in a more specialized auditory task, although the effect of bilingualism did not extend to that domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic activation and episodic odor recognition in young and older adults.

Young, young–old, and old adults were examined in immediate and delayed episodic recognition of common odors. Items were presented in 3 different formats: name-only, odor-only, or odor-name. Ss made familiarity ratings for all items at study. In the delayed recognition test, Ss were asked to name the odors. Young Ss outperformed the 2 older age groups in both recognition tests, although the 2 older groups did not differ. Performance was higher in the odor-name condition than in the single-format conditions. Both familiarity and naming were related to recognition in all age groups. Most important, when naming was statistically controlled, age differences in odor recognition disappeared, suggesting that access to verbal labels largely determine age differences in recognition of common odors. Finally, the finding that recognition was enhanced in both young and older Ss in the odor-name condition suggests that odor memory may involve a similar degree of plasticity as other varieties of episodic memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)