Showing papers in "Neuropsychology (journal) in 2003"
TL;DR: The results suggest that music training systematically affects memory processing in accordance with possible neuroanatomical modifications in the left temporal lobe.
Abstract: The hypothesis that music training can improve verbal memory was tested in children. The results showed that children with music training demonstrated better verbal but not visual memory than did their counterparts without such training. When these children were followed up after a year, those who had begun or continued music training demonstrated significant verbal memory improvement. Students who discontinued the training did not show any improvement. Contrary to the differences in verbal memory between the groups, their changes in visual memory were not significantly different. Consistent with previous findings for adults (A. S. Chan, Y. Ho, & M. Cheung, 1998), the results suggest that music training systematically affects memory processing in accordance with possible neuroanatomical modifications in the left temporal lobe.
561 citations
TL;DR: Though this study indicates that the WCST is sensitive to frontal lobe damage, caveats are discussed and the largest effect size was for dorsolateral damage.
Abstract: 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.
258 citations
TL;DR: In the ADHD group but not in the control group, greater right superior prefrontal volume predicted poorer performance on a test of sustained attention, and patterns of brain abnormality did not differ in male and female children with ADHD.
Abstract: This study compared magnetic resonance imaging size differences in several brain regions and neurocognitive function in a group of male and female children with attention-deficit/hyperactivity disorder (ADHD) with no comorbid learning disorders with a normal control group of children. The ADHD group demonstrated smaller total brain, superior prefrontal, and right superior prefrontal volumes, as well as significantly smaller areas for cerebellar lobules I-V and VIII-X, total corpus callosum area, and splenium. No group differences were observed for the inferior prefrontal, caudate, or cerebellar volumes, or for the area of cerebellar lobules VI-VII. In the ADHD group but not in the control group, greater right superior prefrontal volume predicted poorer performance on a test of sustained attention. Patterns of brain abnormality did not differ in male and female children with ADHD.
238 citations
TL;DR: Two experiments examining effects of eye movements on episodic memory retrieval are reported and implications for neuropsychological mechanisms underlying eye movement desensitization and reprocessing, a therapeutic technique for posttraumatic stress disorder are discussed.
Abstract: Two experiments examining effects of eye movements on episodic memory retrieval are reported. Thirty seconds of horizontal saccadic eye movements (but not smooth pursuit or vertical eye movements) preceding testing resulted in selective enhancement of episodic memory retrieval for laboratory (Experiment 1) and everyday (Experiment 2) events. Eye movements had no effects on implicit memory. Eye movements were also associated with more conservative response biases relative to a no eye movement condition. Episodic memory improvement induced by bilateral eye movements is hypothesized to reflect enhanced interhemispheric interaction, which is associated with superior episodic memory (S. D. Christman & R. E. Propper, 2001). Implications for neuropsychological mechanisms underlying eye movement desensitization and reprocessing (F. Shapiro, 1989, 2001), a therapeutic technique for posttraumatic stress disorder, are discussed.
225 citations
TL;DR: Older participants, who showed a decrease in recollection together with an increase in familiarity, performed better on the forced-choice task than on the yes-no task, whereas younger participants showed the opposite pattern.
Abstract: Whether the format of a recognition memory task influences the contribution of recollection and familiarity to performance is a matter of debate. The authors investigated this issue by comparing the performance of 64 young (mean age = 21.7 years; mean education = 14.5 years) and 62 older participants (mean age = 64.4 years; mean education = 14.2 years) on a yes-no and a forced-choice recognition task for unfamiliar faces using the remember-know-guess procedure. Familiarity contributed more to forced-choice than to yes-no performance. Moreover, older participants, who showed a decrease in recollection together with an increase in familiarity, performed better on the forced-choice task than on the yes-no task, whereas younger participants showed the opposite pattern.
214 citations
TL;DR: In this article, the role of the frontal lobes and the basal ganglia in the inhibition of ongoing responses was investigated, and the results provided evidence for a role of both frontal and basal structures.
Abstract: The authors investigated the role of the frontal lobes and the basal ganglia in the inhibition of ongoing responses. Seventeen patients with frontal lesions (FG), 20 patients with lesions outside the frontal cortex (NFG), 8 patients with lesions to the basal ganglia (BG), and 20 orthopedic controls (OG) performed the stop-signal task that allows the estimation of the time it takes to inhibit an ongoing reaction (stop signal reaction time [SSRT]). The FG and the BG showed significantly longer SSRTs than the OG. Within the FG, patients with right and bilateral lesions showed significantly longer SSRTs than patients with left lesions. Results provide evidence for a role of the frontal lobes and the basal ganglia in the inhibition of ongoing responses.
185 citations
TL;DR: Clinicians may use the proposed predictive model to identify those patients who are at risk of significant intellectual decline, and a steeper decline was found for those with higher baseline performance.
Abstract: Fifty children diagnosed with medulloblastoma completed 188 psychological evaluations using the Wechsler Intelligence Scales for Children (D. Wechsler, 1974, 1991) over a 7-year study period following 35-40 Gy postoperative craniospinal irradiation. Random coefficient models were used to predict the trend in the children's intellectual performance as a function of time since diagnosis, with both patient and treatment variables as parameters of this function. A quadratic model demonstrated a delay prior to decline in performance for older patients, whereas the younger patients showed an immediate loss of performance with a plateau at approximately 6 years postdiagnosis. A steeper decline was found for those with higher baseline performance. Clinicians may use the proposed predictive model to identify those patients who are at risk of significant intellectual decline.
169 citations
TL;DR: Overall, adults with ADHD appear more aware of their problems in social versus emotional skills, and using fewer emotion-related words, despite rating the emotions depicted as more intense than did controls.
Abstract: Social and emotional competence were evaluated using self-report and behavioral measures in adults with attention-deficit/hyperactivity disorder (ADHD) and controls. Adults with ADHD viewed themselves as less socially competent but more sensitive toward violations of social norms than controls. Films depicting emotional interactions were used to assess linguistic properties of free recall and perceived emotional intensity. Although adults with ADHD used more words to describe the scenes, they used fewer emotion-related words, despite rating the emotions depicted as more intense than did controls. In contrast, no group differences for words depicting social or cognitive processes were observed. Overall, adults with ADHD appear more aware of their problems in social versus emotional skills. Findings may have implications for improving the psychosocial functioning of these adults.
161 citations
TL;DR: Young people with Tourette's syndrome (TS) alone, TS plus attention-deficit/hyperactivity disorder (+ADHD), or TS plus obsessive-compulsive disorder (+OCD) were compared with a healthy control group on a set of measures of executive functioning, memory, and learning.
Abstract: Young people with Tourette's syndrome (TS) alone, TS plus attention-deficit/hyperactivity disorder (+ADHD), or TS plus obsessive-compulsive disorder (+OCD) were compared with a healthy control group on a set of measures of executive functioning, memory, and learning. The TS-alone group was impaired on one executive measure involving inhibition and strategy generation but did not differ significantly from the healthy control group on other measures. The TS+ADHD group showed impairment on several executive measures. There was no evidence of impairment in implicit aspects of memory and learning for any of the TS groups. The findings are discussed in terms of the frontostriatal hypothesis of TS and the contribution of comorbid symptomatology.
146 citations
TL;DR: The present findings suggest that the basal ganglia primarily do not support early automatic syntactic processes during comprehension but rather support processes of syntactic integration.
Abstract: Parkinson's disease (PD) has been associated with a general impairment of procedures and with an impairment of syntactic procedures in particular. The present study investigated comprehension processes in PD using event-related brain potentials (ERPs). PD patients and controls listened to sentences that were either correct or syntactically or semantically incorrect. The language-related ERP component correlated with semantic processes (N400) was present in both groups. In the syntactic domain, early automatic processes (early negativity) appeared normal in PD, whereas late integrational processes (P600) were modulated by this disease. The present findings suggest that the basal ganglia primarily do not support early automatic syntactic processes during comprehension but rather support processes of syntactic integration.
139 citations
TL;DR: Using structural equation modeling (SEM) to clarify the relationship between subjective cognitive complaints and neuropsychological functioning in 160 adults with HIV infection indicated that although depressed mood and medical symptoms influenced cognitive complaints, cognitive complaints were independently associated with poorer neuroPsychological performance.
Abstract: The main objective of this study was to use structural equation modeling (SEM) to clarify the relationship between subjective cognitive complaints and neuropsychological functioning in 160 adults with HIV infection. Participants completed questionnaires assessing cognitive complaints, symptoms of depression, and HIV-related medical symptoms. Neuropsychological tests included measures of attention, verbal fluency, psychomotor skills, learning, memory, and executive skills. SEM was used to test models of the relationships among cognitive complaints, mood, and medical symptoms with neuropsychological functioning. The model indicated that although depressed mood (beta = 0.32, p < .01) and medical symptoms (beta = 0.31, p < .01) influenced cognitive complaints, cognitive complaints were independently associated with poorer neuropsychological performance (beta = 0.39, p < .01). Mood and medical symptoms were significantly correlated but were not significantly associated with neuropsychological skills.
TL;DR: Although mild AD and early PD both impair working memory, the deficits may be related to the interruption of different processes that contribute to WM performance, which may be secondary to deficits in other cognitive capacities, including semantic memory.
Abstract: Alzheimer's disease (AD) and Parkinson's disease (PD) impair working memory (WM). It is unclear, however, whether the deficits seen early in the course of these diseases are similar. To address this issue, the authors compared the performance of 22 patients with mild AD, 20 patients with early PD and without dementia, and 112 control participants on tests of inhibition, short-term memory, and 2 commonly administered tests of WM. The results suggest that although mild AD and early PD both impair WM, the deficits may be related to the interruption of different processes that contribute to WM performance. Early PD disrupted inhibitory processes, whereas mild AD did not. The WM deficits seen in patients with AD may be secondary to deficits in other cognitive capacities, including semantic memory.
TL;DR: Face recognition and fear recognition accuracy were significantly correlated in the female control group but not in women with TS, suggesting that anomalies in amygdala function may be a neurological feature of TS of this karyotype.
Abstract: Face recognition is thought to rely on configural visual processing, Where face recognition impairments have been identified, qualitatively delayed or anomalous configural processing has also been found. A group of women with Turner syndrome (TS) with monosomy for a single maternal X chromosome (45, X-super(m)) showed an impairment in face recognition skills compared with normally developing women. However, normal configural face-processing abilities were apparent. The ability to recognize facial expressions of emotion, particularly fear, was also impaired in this TS subgroup. Face recognition and fear recognition accuracy were significantly correlated in the female control group but not in women with TS. The authors therefore suggest that anomalies in amygdala function may be a neurological feature of TS of this karyotype.
TL;DR: In this article, the authors compared patients with Parkinson's disease, 15 older controls and 109 younger controls in two category-learning tasks and found that the older controls performed the best on both tasks.
Abstract: Sixteen patients with Parkinson's disease (PD), 15 older controls (OCs), and 109 younger controls (YCs) were compared in 2 category-learning tasks. Participants attempted to assign colored geometric figures to 1 of 2 categories. In rule-based tasks, category membership was defined by an explicit rule that was easy to verbalize, whereas in information-integration tasks, there was no salient verbal rule and accuracy was maximized only if information from 3 stimulus components was integrated at some predecisional stage. The YCs performed the best on both tasks. The PD patients were highly impaired compared with the OCs, in the rule-based categorization task but were not different from the OCs in the information-integration task. These results support the hypothesis that learning in these 2 tasks is mediated by functionally separate systems.
TL;DR: Aging of cerebral olfactory regions was studied in 5 younger and 6 older healthy adults, matched by odor discrimination and identification scores, with positron emission tomography during odor sensory stimulation, discrimination, and identification tasks.
Abstract: Aging of cerebral olfactory regions was studied in 5 younger and 6 older healthy adults, matched by odor discrimination and identification scores, with positron emission tomography during odor sensory stimulation, discrimination, and identification tasks. Sensory stimulation engaged bilateral piriform and orbitofrontal regions, but neither discrimination nor identification evoked added temporal or orbital activity. Discrimination involved the hippocampus, implicating its role in serial odor comparisons (olfactory working memory). Left inferior frontal activity during identification may reflect semantic associations. Older participants deactivated the left gyrus rectus/medial orbital gyrus (GR/MOG) during sensory stimulation but activated GR/MOG during discrimination and identification. Adjusting for detection threshold eliminated GR/MOG group differences during sensory stimulation. Diminished threshold may lead to reduced engagement of olfactory association areas.
TL;DR: The authors conclude that Korsakoff's syndrome is associated not only with a memory impairment but also with a global executive deficit, and the decline in the ability to alternate between different responses argues for a restricted neurotoxic effect of alcohol on some frontal lobe areas.
Abstract: The effect of long-term heavy alcohol consumption on brain functions is still under debate. The authors investigated a sample of 17 Korsakoff amnesics, 23 alcoholics without Korsakoff's syndrome, and 21 controls with peripheral nerve diseases, matched for intelligence and education. Executive functions were examined for word fluency, the modified Wisconsin Card Sorting Test, an alternate response task, and an "n-back" working memory task. Korsakoff amnesics, but not alcoholics, showed a marked memory impairment. They also scored lower in each of the executive tasks-the alcoholics only in the alternate response task. This task also correlated with the years of the alcohol dependency. First, the authors conclude that Korsakoff's syndrome is associated not only with a memory impairment but also with a global executive deficit. Second, the decline in the ability to alternate between different responses argues for a restricted neurotoxic effect of alcohol on some frontal lobe areas.
TL;DR: The most outstanding deficit, occurring especially in males, involved impaired capacity to use an intention to regulate purposeful behavior, which occurred independently of general cognitive impairment but was related to depletion of fragile X mental retardation 1 gene protein product.
Abstract: The effects of a fragile X disorder on executive function impairment were assessed in 144 extended families, which included individuals with fragile X premutation and full mutation and their relatives without fragile X. A modification of the maximum-likelihood estimators for pedigree data, as well as ordinal logistic regression, were used in data analysis. The most outstanding deficit, occurring especially in males, involved impaired capacity to use an intention to regulate purposeful behavior. This deficit occurred independently of general cognitive impairment but was related to depletion of fragile X mental retardation 1 gene protein product. The other executive function deficits were accounted for by the general cognitive impairment. Possible mechanisms of the effect of fragile X premutation on impairments of executive functioning are considered.
TL;DR: It was found that the group with frontal lesions displayed significantly stronger imitative response tendencies than the group of patients with nonfrontal lesions and it was shown that the inhibition of imitative responses is functionally unrelated to Stroop interference.
Abstract: It is widely accepted that patients with frontal lesions have problems inhibiting automatic response tendencies. Whereas inhibition deficits of overlearned responses have been extensively investigated using interference tasks like the Stroop task (J. R. Stroop, 1935), it is controversial whether patients with frontal brain lesions also have problems inhibiting imitative responses. Using an interference paradigm, the present study investigated imitative response tendencies in patients with frontal lesions. In addition, it tested whether patients deficient in the inhibition of imitative responses correspondingly have problems inhibiting overlearned responses. It was found that the group with frontal lesions displayed significantly stronger imitative response tendencies than the group with nonfrontal lesions. Furthermore, it was shown that the inhibition of imitative responses is functionally unrelated to Stroop interference.
TL;DR: Item response theory methods were used to derive psychometrically sophisticated measures of global cognition, memory, and executive function derived from commonly used neuropsychological tests that were reasonably matched with linear measurement over an ability range relevant to many important clinical applications.
Abstract: Item response theory methods were used to derive psychometrically sophisticated measures of global cognition, memory, and executive function. Goals were that these measures (a) could be derived from commonly used neuropsychological tests, (b) would have linear measurement properties, and (c) would be psychometrically matched. Scale development was based on a sample of 400 older individuals with cognitive function ranging from normal to demented. Scales were reasonably matched with linear measurement over an ability range relevant to many important clinical applications. Cognitively normal, mild impairment, and dementia participant groups differed on baseline measures and rate of decline. Association of measures with quantitative structural magnetic resonance imaging variables followed expected patterns. This approach to scale development may have applications for other neuropsychological assessment problems.
TL;DR: Large differences between the male groups in favor of heterosexual men on JLO and MR performance revealed possible variations in the parietal cortex between homosexual and heterosexual persons.
Abstract: This study examined the performance of heterosexual and homosexual men and women on 2 tests of spatial processing, mental rotation (MR) and Benton Judgment of Line Orientation (JLO). The sample comprised 60 heterosexual men, 60 heterosexual women, 60 homosexual men, and 60 homosexual women. There were significant main effects of gender (men achieving higher scores overall) and Gender x Sexual Orientation interactions. Decomposing these interactions revealed large differences between the male groups in favor of heterosexual men on JLO and MR performance. There was a modest difference between the female groups on MR total correct scores in favor of homosexual women but no differences in MR percentage correct. The evidence suggests possible variations in the parietal cortex between homosexual and heterosexual persons.
TL;DR: All 4 groups showed the characteristic leftward bias when using the left hand, which suggests a shift from contralateral to right-hemispheric control during puberty and may reflect maturation of the corpus callosum.
Abstract: Normal adults tend to bisect horizontal lines to the left of the objective middle, especially when using the left hand. This bias has been attributed to the dominance of the right hemisphere in spatial attention. The authors investigated the effect of hand use and line position in visual line bisection in right-handed children and adults, classified into 4 different age groups: 10-12, 13-15, 18-21, and 24-53 years (N = 98). All 4 groups showed the characteristic leftward bias when using the left hand. When using the right hand, the youngest group showed a rightward bias, whereas the other 3 groups all showed a leftward bias. This suggests a shift from contralateral to right-hemispheric control during puberty and may reflect maturation of the corpus callosum.
TL;DR: Converging evidence from 3 separate paradigms is presented that strongly suggests children with bilateral spastic cerebral palsy experience impairments in inhibitory control, within the context of current cognitive and neuroanatomical models of inhibition.
Abstract: Evidence from developmental, lesion, and neuroimaging studies indicates that the prefrontal cortex plays a major role in executive abilities, including inhibitory control. Proficient executive performance, however, relies not only on the integrity of the prefrontal cortex but also on its interactions with other brain regions. In the current study, the authors focused on the effect that early damage to the white matter tracts interconnecting prefrontal and other brain regions has on inhibitory control. Data were collected from 13 children with bilateral spastic cerebral palsy and from a control group of 20 children with no history of neurologic compromise. Converging evidence from 3 separate paradigms is presented that strongly suggests these children experience impairments in inhibitory control. Findings are discussed within the context of current cognitive and neuroanatomical models of inhibition. Executive ability is a broad term used to describe an assemblage of higher order cognitive abilities such as strategy use, cognitive flexibility, and inhibitory control (Pennington, 1997; Stuss, 1992). Although spanning a broad spectrum, all of these abilities require the efficient coordination and integration of information across a variety of sensory modalities and cognitive domains (e.g., visuoperceptual, language, and memory). From a neuroanatomical perspective, cognitive integration of this nature appears to be most heavily mediated by a common brain region, the prefrontal cortex (Stuss, Alexander, & Benson, 1997). Because the prefrontal cortex has numerous interconnections with other brain regions, it is well suited to support the synchronization of widely distributed neural activity (Cummings, 1995; Thatcher, 1997). The prefrontal cortex is the last brain region to reach maturity, with development continuing into early adulthood (Krasnegor, Lyon, & Goldman-Rakic, 1997). A particularly important aspect of prefrontal development, and the subsequent enhancement of executive abilities, is the refinement of intricate white matter connections between the prefrontal cortex and other brain regions. Thatcher (1997) suggested that the refinement of prefrontal connections stems from cyclical patterns of neural growth during which synapses are rapidly generated and then selectively pruned. The re
TL;DR: Findings indicated that DAT patients were severely impaired in the alphabetical recall task, whereas the performance of neurologically healthy elderly participants was comparable with theperformance of young adult participants.
Abstract: The effect of manipulation and distracting noise on immediate serial recall was measured in patients with dementia of the Alzheimer type (DAT), neurologically healthy elderly individuals, and young adults. In Experiment 1, the authors compared serial word recall with word recall in alphabetical order. Alphabetical recall requires the active manipulation of the contents of working memory. Findings indicated that DAT patients were severely impaired in the alphabetical recall task, whereas the performance of neurologically healthy elderly participants was comparable with the performance of young adult participants. In Experiment 2, the authors investigated the effect of different irrelevant auditory backgrounds on immediate digit recall. In this task, both elderly participants and DAT patients performed similarly to the group of young adult participants, indicating comparable efficacy to resist auditory distraction.
TL;DR: Executive function difficulties noted in PKU are consistent with attention deficit hyperactivity disorder (ADHD)-inattentive type, whereas maternal PKU offspring had executive function difficulties consistent with ADHD-combined type.
Abstract: This study addresses how the timing of a known biological insult affects the developmental progression of executive functions. The sample consisted of children exposed to elevated levels of phenylalanine, either postnatally, as in phenylketonuria (PKU; n = 46), or prenatally, as in maternal PKU (n = 15). Nonhyperphenylanemic siblings of children with PKU (n = 18) served as controls. Results indicated that elevated levels of phenylalanine are toxic to the neurological systems that manage executive functions and cognitive tempo. This toxicity is dose dependent, with higher levels of phenylalanine being more detrimental. Executive function difficulties noted in PKU are consistent with attention deficit hyperactivity disorder (ADHD)-inattentive type, whereas maternal PKU offspring had executive function difficulties consistent with ADHD-combined type.
TL;DR: Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients and processing speed reduced disease-related variance in all memory variables.
Abstract: Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance.
TL;DR: Veridical scoring of the Logical Memory subtest of the Wechsler Memory Scale provides more sensitive detection of very mild dementia of the Alzheimer type than the current standard criteria for scoring.
Abstract: This study examined the nature of errors in prose recall made in dementia compared with normal aging. Responses by 48 young adults, 47 nondemented older adults, and 70 people with very mild or mild Alzheimer's disease to the Logical Memory subtest of the Wechsler Memory Scale were examined in a propositional analysis. Compared with young adults, healthy older adults showed good immediate recall but deficits in retention over a delay. Demented individuals made errors of omission, not commission, at immediate recall. These errors probably reflect difficulty with attentional control rather than memory per se. In terms of clinical implications, veridical scoring of the Logical Memory subtest provides more sensitive detection of very mild dementia of the Alzheimer type than the current standard criteria for scoring.
TL;DR: Event-related magnetic fields were recorded using magnetoencephalography in children with and without dyslexia while they discriminated between pairs of syllables from a voice onset time series to consistent with the notion that deficits in appreciating the sound structure of both written and spoken language are associated with abnormal neurophysiological activity in temporoparietal language areas in children.
Abstract: Event-related magnetic fields were recorded using magnetoencephalography in children with (n 12) and without (n 11) dyslexia while they discriminated between pairs of syllables from a voice onset time series (/ga/‐/ka/). Nonimpaired readers exhibited left-hemisphere predominance of activity after the resolution of the N1m, whereas children with dyslexia experienced a sharp peak of relative activation in right temporoparietal areas between 300 and 700 ms post‐stimulus onset. Increased relative activation in right temporoparietal areas was correlated with reduced performance on phonological processing measures. Results are consistent with the notion that deficits in appreciating the sound structure of both written and spoken language are associated with abnormal neurophysiological activity in temporoparietal language areas in children with dyslexia.
TL;DR: Differences between control participants and PKU patients were significantly greater in the pursuit task compared with the tracking task, indicating more serious deficits when a higher level of controlled processing is required.
Abstract: This study examined motor control in 61 early and continuously treated patients with phenylketonuria (PKU) and 69 control participants, aged 7 to 14 years. The pursuit task demanded concurrent planning and execution of unpredictable movements, whereas the tracking task required a highly automated circular movement that could be planned in advance. PKU patients showed significantly poorer motor control in both tasks compared with control participants. Deficits were particularly observed for younger patients (age < 11 years). Differences between control participants and PKU patients were significantly greater in the pursuit task compared with the tracking task, indicating more serious deficits when a higher level of controlled processing is required. Correlations with historical phenylalanine levels indicated a later maturation of the level of control required by the pursuit task compared with the tracking task.
TL;DR: The inability of the AD patients to benefit from variable practice suggests that these individuals may have difficulty accessing and/or forming motor schemas.
Abstract: This study examined the acquisition and transfer of a fine motor skill, namely the rotary pursuit, in 99 patients with Alzheimer's disease (AD) and 100 normal controls (NCs). To identify optimal learning strategies, the authors had participants practice the rotary pursuit under constant, blocked, random, or no training conditions. Transfer was assessed using speeds that were different from those practiced during acquisition. AD patients and NCs receiving constant practice outperformed their peers in the blocked and random conditions during acquisition. Whereas all 3 types of practice facilitated transfer in the NCs, AD patients only benefited from constant practice. The inability of the AD patients to benefit from variable practice suggests that these individuals may have difficulty accessing and/or forming motor schemas.
TL;DR: Mixed-factor analysis of covariance revealed that concussed patients used less semantic clustering strategies than control patients at 48 hr postconcussion, whereas minimal differences were found at 2 hr postinjury.
Abstract: Knowledge obtained from longitudinal animal models was used to predict the course of verbal memory deficits in 19 concussed patients and 19 control patients who were given versions of the Hopkins Verbal Learning Test--Revised at 2 hr, 48 hr, and 1 week postconcussion. The physiological literature suggests that concussed patients should exhibit a decline in performance from 2 hr to 48 hr postconcussion on a measure of complex memory strategies. Consistent with this hypothesis, mixed-factor analysis of covariance revealed that concussed patients used less semantic clustering strategies than control patients at 48 hr postconcussion, whereas minimal differences were found at 2 hr postinjury. Furthermore, a chi-square analysis showed that a significant number of concussed patients experienced a decline in the number of semantic clusters they used from 2 hr to 48 hr. No differences were found between the groups at the 1-week testing session.