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Neuropsychology - Vol 31, Iss 7

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Neuropsychology Neuropsychology focuses on (a) basic research, (b) the integration of basic and applied research, and (c) improved practice in the field of neuropsychology. The primary function of Neuropsychology is to publish original, empirical research on the relation between brain and human cognitive, emotional, and behavioral function.
Copyright 2017 American Psychological Association
  • The impact of time and repeated exposure on famous person knowledge in amnestic mild cognitive impairment and Alzheimer’s disease.
    Objective: Famous people knowledge has been shown to be impaired early in Alzheimer’s disease (AD) and amnestic mild cognitive impairment (aMCI). However, the question of whether recently acquired knowledge is more impaired than remotely acquired knowledge remains a matter of debate. The aim of this study was to investigate the patterns of semantic memory impairment in aMCI and AD by investigating 2 factors that may influence the retrieval of such knowledge, namely remoteness and frequency of repetition of information over time. Method: Three groups (19 controls, 20 aMCI, and 20 AD patients) were compared on a test assessing general and specific biographical knowledge about famous people, where the period of acquired fame (remote vs. recent) and the type of fame (enduring vs. transient) were controlled for. Results: Global performance of aMCI and AD patients was significantly poorer than that of controls. However, different patterns of recall were observed as a function of time and type of fame. A temporal gradient was found in both patient groups for enduring names but not for transient ones, whereby knowledge about remote enduring famous persons was better recalled. Patients were more impaired at questions assessing specific biographical knowledge (unique to an individual) than more general knowledge. Conclusions: Tests of famous people knowledge offer a unique opportunity to investigate semantic deficits in aMCI and AD, because they make it possible to estimate the time at which memories were acquired, as well as the type of fame. Results are discussed in light of memory consolidation models. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Process dissociation analyses of memory changes in healthy aging, preclinical, and very mild Alzheimer disease: Evidence for isolated recollection deficits.
    Objective: Recollection and familiarity are independent processes that contribute to memory performance. Recollection is dependent on attentional control, which has been shown to be disrupted in early stage Alzheimer’s disease (AD), whereas familiarity is independent of attention. The present longitudinal study examines the sensitivity of recollection estimates based on Jacoby’s (1991) process dissociation procedure to AD-related biomarkers in a large sample of well-characterized cognitively normal middle-aged and older adults (N = 519) and the extent to which recollection discriminates these individuals from individuals with very mild symptomatic AD (N = 64). Method: Participants studied word pairs (e.g., knee bone), then completed a primed, explicit, cued fragment-completion memory task (e.g., knee b_n_). Primes were either congruent with the correct response (e.g., bone), incongruent (e.g., bend), or neutral (e.g., &&&). This design allowed for the estimation of independent contributions of recollection and familiarity processes, using the process dissociation procedure. Results: Recollection, but not familiarity, was impaired in healthy aging and in very mild AD. Recollection discriminated cognitively normal individuals from the earliest detectable stage of symptomatic AD above and beyond standard psychometric tests. In cognitively normal individuals, baseline CSF measures indicative of AD pathology were related to lower initial recollection and less practice-related improvement in recollection over time. Finally, presence of amyloid plaques, as imaged by PIB-PET, was also related to less improvement in recollection over time. Conclusions: These findings suggest that attention-demanding memory processes, such as recollection, may be particularly sensitive to both symptomatic and preclinical AD pathology. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • A lower ratio of omega-6 to omega-3 fatty acids predicts better hippocampus-dependent spatial memory and cognitive status in older adults.
    Objective: Evidence from several cross-sectional studies indicates that an increase in omega-6 to omega-3 fatty acids (FAs) may negatively affect cognition in old age. The hippocampus is among the first neural structures affected by age and atrophy in this brain region is associated with cognitive decline. Therefore, we hypothesized that a lower omega-6:3 FA ratio would predict better hippocampus-dependent spatial memory, and a higher general cognitive status. Method: Fifty-two healthy older adults completed a Food Frequency Questionnaire, the Montreal Cognitive Assessment test (MoCA; a test of global cognition) and virtual navigation tasks that assess navigational strategies and spatial memory. Results: In this cross-sectional study, a lower ratio of omega-6 to omega-3 FA intake strongly predicted more accurate hippocampus-dependent spatial memory and faster learning on our virtual navigation tasks, as well as higher cognitive status overall. Conclusions: These results may help elucidate why certain dietary patterns with a lower omega-6:3 FA ratio, like the Mediterranean diet, are associated with reduced risk of cognitive decline. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Spontaneous retrieval deficits in amnestic mild cognitive impairment: A case of focal event-based prospective memory.
    Objective: Research on early cognitive markers of Alzheimer’s disease is primarily focused on retrospective recall (of word lists, pairs of items, stories) and executive functions. However, research shows that people with amnestic mild cognitive impairment (aMCI), who are at a higher risk of developing the disease than healthy controls, are particularly impaired in remembering to do things in the future or prospective memory (PM). The aim of this study was to establish which type of event-based PM is particularly disrupted in aMCI, focal PM, based on spontaneous retrieval, or nonfocal PM that relies on strategic monitoring processes. Method: Thirty-eight aMCI individuals and 46 age- and education-matched healthy older adults identified the profession of each famous face presented (ongoing task) and, additionally, responded to certain professions (focal PM condition), or to certain physical features of a person presented (nonfocal PM). Only 4 aMCI individuals could not remember PM instructions at the end of the session, and were excluded from analyses. Results: In comparison with healthy controls, participants with aMCI were significantly impaired in the focal PM task, but not on the nonfocal task. In both groups, monitoring indices were significantly higher in the nonfocal than focal PM condition. Conclusions: The results fully replicate and extend initial findings of Chi et al. (2014) and McDaniel, Shelton, Breneiser, Moynan, and Balota (2011), showing substantial spontaneous retrieval deficits in PM performance of aMCI individuals. Possible brain mechanisms involved in this deficit are discussed and a novel hypothesis of more generic spontaneous retrieval deficits in aMCI is proposed. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Counting ability in Down syndrome: The comprehension of the one-to-one correspondence principle and the role of receptive vocabulary.
    Objective: The authors investigated whether children with Down’s syndrome (DS) who have not started to produce number words understand the one-to-one correspondence principle (Experiment 1), and they looked at the relationship between number word knowledge and receptive vocabulary (Experiment 2). Method: Sixteen children with DS who did not recite the count list participated in Experiment 1, along with 2 comparison groups: 1 of 16 children with DS who recited up to 10, paired by chronological age, and another of 16 typically developing children paired by their ability to recite the list. The understanding of the principle was evaluated by a preferential looking task. Children saw 1 of 2 conditions. In the number condition, they heard number words and in the beep condition they heard computerized beeps. In both conditions, children saw videos depicting counting events that were principle-consistent or principle-inconsistent. Experiment 2 evaluated 25 children with DS using the Give-a-Number task and the Receptive Vocabulary subtest of the Wechsler Preschool and Primary Scale of Intelligence-III. Results: In Experiment 1, children in the number condition preferred principle-consistent videos, independent of their ability to recite the count list. Experiment 2 showed a strong correlation between number word knowledge and receptive vocabulary scores, independent of chronological age. Conclusions: The results suggest that the difficulty of children with DS in acquiring counting ability might not reflect a lack of understanding of the one-to-one correspondence principle, but might instead be related to vocabulary development. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Phonological ambiguity modulates resolution of semantic ambiguity during reading: An fMRI study of Hebrew.
    Objectives: The current fMRI study examined the role of phonology in the extraction of meaning from print in each hemisphere by comparing homophonic and heterophonic homographs (ambiguous words in which both meanings have the same or different sounds respectively, e.g., bank or tear). The analysis distinguished between the first phase, in which participants read ambiguous words without context, and the second phase in which the context resolves the ambiguity. Method: Native Hebrew readers were scanned during semantic relatedness judgments on pairs of words in which the first word was either a homophone or a heterophone and the second word was related to its dominant or subordinate meaning. Results: In Phase 1 there was greater activation for heterophones in left inferior frontal gyrus (IFG), pars opercularis, and more activation for homophones in bilateral IFG pars orbitalis, suggesting that resolution of the conflict at the phonological level has abolished the semantic ambiguity for heterophones. Reduced activation for all ambiguous words in temporo-parietal regions suggests that although ambiguity enhances controlled lexical selection processes in frontal regions it reduces reliance on bottom-up mapping processes. After presentation of the context, a larger difference between the dominant and subordinate meaning was found for heterophones in all reading-related regions, suggesting a greater engagement for heterophones with the dominant meaning. Conclusions: Altogether these results are consistent with the prominent role of phonological processing in visual word recognition. Finally, despite differences in hemispheric asymmetry between homophones and heterophones, ambiguity resolution, even toward the subordinate meaning, is largely left lateralized. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Normal-range verbal-declarative memory in schizophrenia.
    Objective: Cognitive impairment is prevalent and related to functional outcome in schizophrenia, but a significant minority of the patient population overlaps with healthy controls on many performance measures, including declarative-verbal-memory tasks. In this study, we assessed the validity, clinical, and functional implications of normal-range (NR), verbal-declarative memory in schizophrenia. Method: Performance normality was defined using normative data for 8 basic California Verbal Learning Test (CVLT-II; Delis, Kramer, Kaplan, & Ober, 2000) recall and recognition trials. Schizophrenia patients (n = 155) and healthy control participants (n = 74) were assessed for performance normality, defined as scores within 1 SD of the normative mean on all 8 trials, and assigned to normal- and below-NR memory groups. Results: NR schizophrenia patients (n = 26) and control participants (n = 51) did not differ in general verbal ability, on a reading-based estimate of premorbid ability, across all 8 CVLT-II-score comparisons or in terms of intrusion and false-positive errors and auditory working memory. NR memory patients did not differ from memory-impaired patients (n = 129) in symptom severity, and both patient groups were significantly and similarly disabled in terms of functional status in the community. Conclusion: These results confirm a subpopulation of schizophrenia patients with normal, verbal-declarative-memory performance and no evidence of decline from higher premorbid ability levels. However, NR patients did not experience less severe psychopathology, nor did they show advantage in community adjustment relative to impaired patients. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Cognitive clusters in first-episode psychosis: Overlap with healthy controls and relationship to concurrent and prospective symptoms and functioning.
    Objective: To identify cognitive subgroups (comprising neurocognition and social cognition domains) within first-episode psychosis (FEP) patients including a healthy control group for comparison. Predictive validity of cognitive clusters in relation to symptoms and functioning was also investigated. Method: A comprehensive cognitive battery was administered to 133 FEP participants and 46 healthy controls. Ward’s method hierarchical agglomerative cluster analysis with k-means verification was used to determine clusters. Clusters were externally validated and 6-month predictive validity was also examined. Results: Three distinct clusters were identified and were defined by degree of impairment rather than specific deficit profiles. Social–cognitive performance mirrored neurocognitive performance in each cluster. Cluster 1 was characterized by significant widespread cognitive impairments (1–2 SD below the mean) and solely comprised FEP participants (n = 24). Cluster 2 suggested moderately impaired cognitive functioning (within 0.5 SD below the mean), and comprised mostly FEP participants and 2 healthy controls (n = 73). Cluster 3 showed a pattern of cognitively intact performance across domains and comprised 37 FEP participants and 44 healthy controls (n = 81). Premorbid IQ, negative symptom severity, and functioning were significantly associated with cluster membership at baseline. At 6-month follow-up, cluster membership remained significantly associated with negative symptoms and functioning. Conclusions: The heterogeneity of cognition in FEP may be based on degree of impairment across both neurocognitive and social–cognitive domains. Cognitive clusters were associated with symptom and functional outcome, suggesting that measurement of cognition at entry to treatment may be useful for prognosis and treatment. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Determinants of risk-taking in HIV-associated neurocognitive disorders.
    Objective: Decision-making involves fronto-striatal brain areas that are particularly vulnerable to the effects of HIV infection. Some studies report impaired decision-making in people with HIV/AIDS with past or present addictions and/or accompanying HIV-associated neurocognitive disorders (HAND). The authors investigated risk-based decision-making in HIV/AIDS, separating individuals with or without accompanying HAND. Method: A total of 288 HIV-infected persons underwent standardized neuropsychological testing. Participants were profiled based on neuropsychological and clinical assessments into 2 groups, neurocognitively normal (NN, n = 205) and HAND (n = 83). Risk-based decision-making was assessed via the Game of Dice Task (GDT). Sample characteristics were summarized by principal component analysis (PCA) prior to regression analyses predicting GDT performance. Results: The NN group performed within the normative range of the GDT, but the HAND group was impaired in all GDT measures. Across all participants, GDT performance was predicted by a combination of psychiatric comorbidities, alcohol abuse, education/premorbid IQ, and neuropsychological performance. Further analyses revealed marijuana use as an important additional predictor of impaired GDT performance. Within the GDT-impaired HAND group only, past or present immunosuppression emerged as the most robust predictor of GDT performance. Metabolic disorders and antiretroviral toxicity were also predictors of GDT performance in the HAND group. Conclusion: The majority of HIV-infected individuals were unimpaired in the GDT. Some influence of psychiatric and substance use comorbidities on GDT performance emerged in the entire cohort. However, GDT deficits were restricted to individuals with HAND, related to immunosuppression, metabolic disorders and antiretroviral toxicity in this group only. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Neuropsychological correlates of theory of mind deficits in patients with multiple sclerosis.
    Background: Theory of mind (ToM) is the ability to understand and interpret another person’s beliefs, intentions (cognitive ToM) and emotions (affective ToM). Objective: To explore affective and cognitive ToM and their neuropsychological correlates in patients affected by multiple sclerosis (MS). Material and Method: Forty MS patients and 40 matched control individuals underwent tasks assessing cognitive (the ToM Pictures Sequencing Task and the Advanced Test of ToM) and affective ToM (the Reading the Mind in the Eyes Task and the Emotion Attribution Task), in both verbal and nonverbal modality, a comprehensive neuropsychological battery, and questionnaires for behavioral disorders. Results: MS patients performed significantly worse than controls on tasks assessing cognitive and affective ToM, in verbal and nonverbal modality. Moreover, MS patients achieved significantly lower scores on tests assessing visuospatial learning and speed of spatial information processing, and significantly higher scores on scales for alexithymia and depression with respect to controls. After covarying for cognitive and behavioral variables different in the 2 groups, the differences between patients and controls on ToM tasks remained significant. ToM abilities were significantly related to executive functions, but not to depressive, anxious and apathetic symptoms. Higher alexithymia scores were associated with poor recognition of others’ mental states. Conclusion: The findings demonstrated that both affective and cognitive aspects of ToM are impaired in nondemented and mildly to moderately disabled MS and suggest that impaired social cognition can occur independently from behavioral disorders. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Shifts of spatial attention underlie numerical comparison and mental arithmetic: Evidence from a patient with right unilateral neglect.
    Objectives: Recent findings suggest that mental arithmetic involves shifting attention on a mental continuum in which numbers would be ordered from left to right, from small to large numbers, with addition and subtraction causing rightward or leftward shifts, respectively. Neuropsychological data showing that brain-damaged patients with left neglect experience difficulties in solving subtraction but not addition problems support this hypothesis. However, the reverse dissociation is needed to establish the causal role of spatial attention in mental arithmetic. Method: R.H., a 65-year-old left-brain-damaged patient exhibiting right unilateral visuospatial and representational neglect, was tested with various numerical tasks including numerical comparison, arithmetic problem-solving, and numerical interval bisection. Results: In numerical comparison, R.H. showed a selective response latency increase when judging numbers larger than the references whereas his performance was normal for numbers smaller than the references. In the arithmetic task, R.H. was impaired in solving addition but not subtraction problems. In contrast, performance in number bisection shows a deviation toward larger numbers. Conclusion: These results establish a double dissociation between subtraction and addition solving in patients with left versus right neglect and demonstrate clear evidence that attentional mechanisms are crucial for mental arithmetic. We suggest that attention shifts are involved whenever a number is represented relative to another on a mental continuum, be it during numerical comparison or arithmetic problem-solving. R.H.’s performance in numerical interval bisection indicates that this task involves processes that are distinct from those involved in number comparison and mental arithmetic. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Arithmetical calculation and related neuropsychological skills in subjects with isolated oral clefts.
    Objective: The current study examined whether the arithmetical calculation skills of children, adolescents, and young adults with isolated cleft of the lip and/or palate (iCL/P) differ significantly from unaffected control participants. Comparisons of potential neuropsychological predictors of arithmetical calculation were also conducted to determine whether these variables differ significantly for participants with iCL/P. Method: Participants (N = 176; 93 iCL/P and 83 Control) ranged in age from 7 to 26 years old. A standardized battery of achievement and neuropsychological skills was administered. Between group differences on math achievement was assessed through a univariate analysis of covariance. Relationships between neuropsychological measures and math achievement were analyzed separately for participants with iCL/P and controls through hierarchical linear regressions. Results: Arithmetical calculation was significantly lower for the iCL/P group. Rapid naming, sustained attention, and visual-spatial organization were significant predictors for the iCL/P group; rapid naming was the lone variable that was significantly more predictive of arithmetical calculation for the iCL/P group than for control participants. Conclusions: These results suggest that inefficient verbal label retrieval related to short-term memory (STM) deficits underlie the calculation difficulties of individuals with iCL/P. These findings have implications for approaches to remediation, as well as future research. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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