Visuomotor adaptation and its relationship with motor ability in children with and without autism spectrum disorder

The high prevalence rates of motor impairments among individuals with autism spectrum disorder (ASD) lead to increased attention to motor learning. The current study examined the visuomotor adaptability in children with and without ASD using a computerized visuomotor adaptation task in which the real-time visual feedback of hand movement was rotated. The relationships between visuomotor adaptability and clinical symptomology were also investigated. Results revealed that the children with ASD showed a slower rate of improvement and smaller after-effects than their peers on the measures of motor planning. Additionally, autistic characteristics significantly moderated the association between individuals' adaptability and fine motor skills. The findings contribute to the growing evidence of compromised visuomotor adaptability, which suggested the importance of addressing these clinical features of ASD.     

Impaired performance of children exposed in utero to cocaine on a novel test of visuospatial working memory

The present study examines the potentially harmful effects of prenatal cocaine exposure on later visuospatial memory functions. A novel neuropsychological measure of immediate- and short-term memory for visuospatial information was administered to 40 children, who were identified as cocaine-exposed, and 11 age and socioeconomic status matched controls (all children were 8-9 years old). The Groton Maze Learning Test is a computer-based hidden maze learning test that consists of a 'timed chase test' (a simple measure of visuomotor speed), 5 learning trials on a hidden maze, followed by a delayed recall trial after an 8 min delay. The specific test parameters are chosen based on the age cohort of the subjects. The cocaine-exposed group performed significantly slower on the 'timed chase test,' the last 3 learning trials, and the delayed recall trial (p < or = .05 for all comparisons). Although there was a modest trend for the cocaine-exposed group to make more errors throughout the learning trials, there were no significant group differences. These results suggest that children who were exposed in utero to cocaine exhibit slowed visuomotor speed, a possible impairment in procedural learning, and diminished efficiency in accessing and using the internal spatial map that subjects create to master the maze.     

Impact of Parkinson’s disease and dopaminergic medication on adaptation to explicit and implicit visuomotor perturbations

The capacity to learn new visuomotor associations is fundamental to adaptive motor behavior. Evidence suggests visuomotor learning deficits in Parkinson’s disease (PD). However, the exact nature of these deficits and the ability of dopamine medication to improve them are under-explored. Previous studies suggested that learning driven by large and small movement errors engaged distinct neural mechanisms. Here, we investigated whether PD patients have a generalized impairment in visuomotor learning or selective deficits in learning from large explicit errors which engages cognitive strategies or small imperceptible movement errors involving primarily implicit learning processes. Visuomotor learning skills of non-medicated and medicated patients were assessed in two reaching tasks in which the size of visuospatial errors experienced during learning was manipulated using a novel three-dimensional virtual reality environment. In the explicit perturbation task, the visuomotor perturbation was applied suddenly resulting in large consciously detected initial spatial errors, whereas in the implicit perturbation task, the perturbation was gradually introduced in small undetectable steps such that subjects never experienced large movement errors. A major finding of this study was that PD patients in non-medicated and medicated conditions displayed slower learning rates and smaller adaptation magnitudes than healthy subjects in the explicit perturbation task, but performance similar to healthy controls in the implicit perturbation task. Also, non-medicated patients showed an average reduced deadaptation relative to healthy controls when exposed to the large errors produced by the sudden removal of the perturbation in both the explicit and implicit perturbation tasks. Although dopaminergic medication consistently improved motor signs, it produced a variable impact on learning the explicit perturbation and deadaptation and unexpectedly worsened performance in some patients. Considered together, these results indicate that PD selectively impairs the ability to learn from large consciously detected visuospatial errors. This finding suggests that basal ganglia-related circuits are important neural structures for adaptation to sudden perturbations requiring awareness and high-cost action selection. Dopaminergic treatment may selectively compromise the ability to learn from large explicit movement errors for reasons that remain to be elucidated.     

Gender Differences in Cognitive and Emotional Adjustment to Traumatic Brain Injury

This study examined gender differences in cognitive and emotional status after traumatic brain injury (TBI) among 262 men and 140 women with TBI referred for neuropsychological evaluations. In this cross-sectional study, cognition was measured in terms of both absolute level of functioning (i.e., raw/standard scores) and estimated decline from premorbid levels expressed as z-deficit scores in the following domains: intelligence [Wechsler Adult Intelligence Scale—Revised (WAIS-R)], memory and attention [Wechsler Memory Scale—Revised (WMS-R)], processing speed (Trails A), and cognitive flexibility (Trails B). Emotional functioning was measured in terms of depression (Beck Depression Inventory) and general emotional distress (Brief Symptom Inventory). Kruskal–Wallis nonparametric one-way ANOVAs indicated that women and men differed significantly on 2 of 8 raw/standard cognitive scores [men demonstrated lower WMS-R General Memory (p < .05) and Trails B scores (p < .0001) and 4 of 8 relative decline scores [women demonstrated more estimated change in VIQ (Verbal IQ) [p < .0001], FSIQ (Full Scale IQ) [p < .01], and Attention (p < .01)]; men demonstrated greater estimated z-decline scores on Trails B (p < .01)]. Women reported significantly higher levels of depression (p < .01), but men endorsed significantly greater general psychological distress (p < .05). Research and assessment recommendations are suggested.     

Inhibition and shifting in children with learning deficits in arithmetic and reading

The executive functions of inhibition and shifting were studied in arithmetic-disabled children, reading-disabled children, reading plus arithmetic-disabled children, and controls (N = 74). Measures involved the rapid naming of objects, digits, letters, or quantities with or without additional task requirements that reflected inhibition or shifting. Also, the Making Trails task, reflecting shifting, was administered. For tasks without executive demands, arithmetic-disabled children were slower in the naming of digits and quantities, whereas reading-disabled children were slower in the naming of digits and letters. For the executive tasks, arithmetic-disabled children as well as reading plus arithmetic-disabled children were impaired on the Making Trails task and on an object naming task that required both inhibition and shifting. Reading-disabled children exhibited no problems in executive functioning. Furthermore, it was shown that reading plus arithmetic-disabled children experienced the combination of problems that characterize children with a single learning deficit.     

阅读障碍儿童的技能自动化能力

以自动化缺陷假说为理论背景,采用系列反应时学习任务,探讨了41名五、六年级的汉语发展性阅读障碍儿童和41名正常儿童的技能自动化能力,通过比较对系列刺激和随机刺激的反应时差异,发现障碍组儿童的反应时虽然普遍长于正常组,但两组儿童都表现出了相同模式的系列学习效应,不支持发展性阅读障碍的技能自动化缺陷假说.     

The role of encoding strategies in the verbal memory performance in patients with schizophrenia

Background. Verbal learning and memory is often compromised in patients with schizophrenia who prefer encoding words in order of their presentation (serial clustering) rather than using semantic categories (semantic clustering). Method. One hundred and four in‐patients with schizophrenia were assessed twice with the California Verbal Learning Test. Results. Patients showed significantly less semantic than serial clustering at both assessment times. Usage of encoding strategies were not stable over time. An increase in semantic clustering improved recall and recognition performance. Conclusions. Patients with schizophrenia should be taught to use the more effective encoding strategy of semantic clustering in order to improve their memory performance.     

Word,nonword, and visual paired associate learning in Dutch dyslexic children

Verbal and non-verbal learning were investigated in 21 8-11-year-old dyslexic children and chronological-age controls, and in 21 7-9-year-old reading-age controls. Tasks involved the paired associate learning of words, nonwords, or symbols with pictures. Both learning and retention of associations were examined. Results indicated that dyslexic children had difficulty with verbal learning of both words and nonwords. In addition, analysis of the errors made during nonword learning showed that both phonological errors and general learning errors were distributed similarly for the reading groups. This suggests that nonword learning in dyslexics is slower, but not qualitatively different from normal readers. Furthermore, no differences were found between the dyslexics and age-matched normal readers on non-verbal learning. Long-term retention of the learned visual-verbal associations (both words and nonwords) was not impaired in dyslexic children as compared to normal readers. Finally, phonological awareness ability was assessed. Dyslexics performed worse than age-matched normal readers, but similar to reading-age controls.     

Different visuomotor processes maturation rates in children support dual visuomotor learning systems

Different processes are involved during visuomotor learning, including an error-based procedural and a strategy based cognitive mechanism. Our objective was to analyze if the changes in the adaptation or the aftereffect components of visuomotor learning measured across development, reflected different maturation rates of the aforementioned mechanisms. Ninety-five healthy children aged 4–12 years and a group of young adults participated in a wedge prism and a dove prism throwing task, which laterally displace or horizontally reverse the visual field respectively. The results show that despite the age-related differences in motor control, all children groups adapted in the error-based wedge prisms condition. However, when removing the prism, small children showed a slower aftereffects extinction rate. On the strategy-based visual reversing task only the older children group reached adult-like levels. These results are consistent with the idea of different mechanisms with asynchronous maturation rates participating during visuomotor learning.     

Neuropsychological Functioning in Children with Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) has been associated with deficits in the areas of verbal memory and learning, executive functioning, working memory, and attention in adults. Findings have been less consistent in the few studies examining neuropsychological functioning in childhood PTSD, which are often limited by comparing children with PTSD to children without trauma histories, making it unclear whether observed neuropsychological deficits are related to trauma exposure or to PTSD symptomatology. In an ethnically diverse sample of 62 children who witnessed intimate partner violence (n = 27 PTSD+ and 35 PTSD?), children with PTSD exhibited slower and less effective learning, heightened sensitivity to interference, and impaired effect of rehearsal on memory acquisition on the California Verbal Learning Test – Children's Version, a word list learning task. Both groups performed in the below average range on measures of executive functioning, attention, and intellectual ability.     

On the nature of the verbal memory deficit in Alzheimer''s disease

Verbal memory was investigated in patients with Alzheimer's disease (AD) with previously documented deficits in word production and comprehension. Procedures were employed to evaluate word recall and recognition within the context of both "multistore" and "levels of processing" models of memory. In addition, memory abilities were evaluated with respect to performance on measures of verbal fluency and language comprehension. As expected, the AD patients performed significantly worse than normal individuals on all tasks. However, in each experiment their pattern of recall across conditions was found to be qualitatively similar to that produced by normal subjects. It was argued that the memory impairment associated with Alzheimer's disease may be largely due to an inability to encode a sufficient number of stimulus features or attributes. Furthermore, this encoding deficit includes, but is not limited to, semantic attributes. Similarities between the performance of the AD patients and reported findings with Korsakoff patients and normal subjects with "weak" memory were discussed.     

Emotional impact on trail making test performance

This study assessed the effect of emotional factors on Trail Making Test Part B performance for a sample of 105 neuropsychological referrals for whom there was no neurodiagnostic evidence of brain damage. Trails B scores declined in relation to elevated MMPI scores on Scales 6, 7, and 8, though only nine patients performed within the impaired range. The results suggest that (a) Trails B performance is resilient to a variety of emotional influences, (b) psychotic symptoms and severe anxiety impede Trails B performance, though rarely to the extent caused by brain damage, and (c) the MMPI provides objective criteria that help rule out emotional effects on Trails B performance.     

Visuomotor perception in children with attention deficit hyperactivity disorder--combined type.

Children with Attention Deficit Hyperactivity Disorder--Combined Type (ADHD-CT) defined by behavioral characteristics of inattention, impulsivity, and hyperactivity including weaknesses in fine motor coordination and poor motor inhibition frequently exhibit poor handwriting and penmanship. Performance of children on visuomotor tasks is further complicated, as most studies have not excluded children with specific learning disabilities who are known to do poorly on these tests. This study was designed to examine the performance of children diagnosed with this disorder, without learning disabilities on visuomotor tasks. 26 preadolescent patients were administered a battery of tests that included the Bender-Gestalt, Conners' Parent Rating Scale, Continuous Performance Task, and Wide Range Achievement Test-Third Edition Scores on the Bender-Gestalt test averaged significantly lower than Koppitz normative data. This study lends support to the hypothesis that ADHD-CT children without learning disabilities exhibit deficits on tasks requiring visuomotor perception.     

Effects of cigarette smoking on verbal rote learning and physiological arousal

Abstract.— Verbal rote learning was studied on 12 moderate smokers. In one condition learning was interrupted twice by smoking a nicotine-containing cigarette (Virginia King, 2.1 mg nicotine) and in another condition by smoking a nicotine-free cigarette. Immediately after the first nicotine-containing cigarette there was a drop in the number of correct responses and learning was significantly less rapid under subsequent trials as compared with learning after the first nicotine-free cigarette. After the second cigarette the picture was reversed. Learning was significantly more improved in the nicotine condition than in the nicotine-free condition. Adrenalin excretion increased significantly during learning in both conditions, and heart rate increased significantly after the first nicotine-containing cigarette.     

Visuospatial working memory in school-aged children exposed in utero to cocaine.

OBJECTIVE: Among the neurocognitive impairments reported as associated with prenatal cocaine exposure, slower response time, and less efficient learning in school-aged children are common to findings from several laboratories. This study presents performance data on a spatial working memory task in 75 prenatally cocaine exposed (CE) and 55 nondrug-exposed (NDE) 8- to 10-year-old children. METHODS: Children were administered a novel neuropsychological measure of immediate- and short-term memory for visuospatial information, the Groton Maze Learning Test (GMLT), a computer-based hidden maze learning test that consists of a "timed chase test" (a simple measure of visuomotor speed), eight learning trials followed by a delayed recall trial after an 8-minute delay and a reverse learning trial. Performance is expressed as correct moves per second and number of errors per trial. RESULTS: Across all trials, the cocaine-exposed group showed significantly slower correct moves per second and made significantly more errors. There were no significant main effects for amounts of alcohol, tobacco, or marijuana exposure. After an 8-minute delay and compared to the eighth trial, cocaine-exposed children showed less consolidation in learning compared to nonexposed children. When asked to complete the maze in reverse, cocaine-exposed children showed a greater decrement in performance (decreased correct moves per second and increased errors) compared to the eighth learning trial. CONCLUSIONS: Children exposed in utero to cocaine exhibit a possible impairment in procedural learning and diminished efficiency in creating and accessing an internal spatial map to master the hidden maze.     

Neurological subtle signs and cognitive development: A study in late childhood and adolescence

Introduction and Aim: Neurological subtle signs (NSS) are often observed during the neurological examination of children and tend to disappear with age. Their persistence into late adolescence or young adulthood has been related to psychiatric and neurocognitive disorders. To provide a better understanding of their functional basis, a longitudinal correlational study with neurocognitive measurements was performed.

Method: We conducted multiple regression and correlation analyses of NSS with demographic and cognitive measures on a subset of 341 healthy children (56% males), taking part in a longitudinal dental study. Participants, whose ages ranged between 11–15 years, at first evaluation, undertook yearly, during 5 years, a 6-item NSS exam (producing a total score ranging between 0–18) and a comprehensive battery of neurocognitive tests. Effects of age, gender, IQ, and 7 neurocognitive factors on NSS were analyzed.

Results: Over the years, NSS scores correlated consistently with selective attention (Stroop test), motor speed (finger tapping), and visuomotor speed (pegboard speed).

Discussion: These results suggest that the disappearance of NSS in late childhood and adolescence occurs primarily in parallel with the development of motor and visuomotor functions and secondarily in relation to higher order functions such as selective attention (Stroop) and executive control (B-A Trails difference).     

Sex Differences in Vulnerability to Developmental Spatial Learning Deficits Induced by Limited Binge Alcohol Exposure in Neonatal Rats

The two main objectives of this study were (1) to replicate previous findings that 6 days of binge-like exposure to alcohol during the neonatal brain growth spurt induces significant place learning deficits in juvenile rats and (2) to determine whether more limited (3-day) binge-like exposure during the neonatal period induces place learning deficits and whether the effects depend on the developmental timing of the exposure. Using artificial rearing methods and a split-litter experimental design, groups of male and female neonatal rats were given binge-like exposure to 4.5 g/kg/day of ethanol in milk formula either on Postnatal Days (PD) 4–6, PD 7–9, or PD 4–9, which yielded mean peak blood alcohol concentrations of 230–260 mg/dl. Controls included an artificially reared gastro- stomy control group (GC) given an isocaloric milk formula diet on PD 4–9 and a suckle control group reared normally by lactating dams. Acquisition of place learning in the Morris spatial navigation task was trained for 6 consecutive days beginning on PD 26; a probe trial was given at the end of the sixth day. As expected, both males and females given alcohol on PD 4–9 had significant deficits in acquisition and probe trial performance relative to SC and GC groups. Males given the PD 7–9 exposure had significant place learning deficits which were as severe as with the full 6-day exposure. The PD 4–6 exposure in males produced only a nonsignificant trend toward slower acquisition. Females were not significantly affected by either 3-day exposure. The latter phase of the neonatal brain growth spurt appears to constitute a sex-specific period of enhanced vulnerability to alcohol-induced developmental spatial learning deficits.     

Memory deficits in Alzheimer's patients: A comprehensive review

Despite considerable experimental work on Alzheimer's disease (AD), the underlying cognitive mechanisms as well as the precise localization of neuropathological changes critical for memory loss remains undefined. A review of the neuropsychological literature on long-term memory deficits in AD patients suggests that AD patients display (a) a pervasive deficit of explicit memory, (b) a partial deficiency of implicit memory for verbal and visuoperceptual material (as measured by repetition priming procedures), and (c) a substantial sparing of implicit memory for visuomotor skills. The explicit memory loss is likely a result of encoding as well as consolidation difficulties. A faulty lexical-semantic knowledge structure appears responsible for deficient repetition priming effects. Since neuropathological changes diffusely affect the brain of AD patients, establishing a clear relationship between localization of cerebral lesions and memory deficits is particularly difficult. Nevertheless, data suggest that extensive involvement of the hippocampal-amygdala complex plays a major role in explicit memory loss. Damage to associative cortical areas likely is involved in repetition priming deficits. The relative integrity of primary motor and sensory cortical areas and of the basal ganglia likely subsume, by contrast, the normal learning of visuomotor skills.     

Spatial and visual learning deficits in Alzheimer's and Parkinson's disease

Experimental paradigms adopted from animal models were used to compare the neuropsychological mechanisms underlying the dementias of Alzheimer's and Parkinson's diseases. Two tasks were selected because characteristic profiles of impairment in nonhuman primates are seen following selective lesions of frontal cortex, temporal cortex, and fornix. The tasks consisted of a spatial and a visual learning problem, each with two components: (1) original learning and (2) reversal of the original learning. The Alzheimer's patients were significantly impaired on original learning and reversal learning in the visual modality compared with demented Parkinson's patients, even though both groups were equated for severity of dementia. On the spatial tasks, both the Alzheimer's and the demented Parkinson's patients were impaired on reversal learning but not on original learning. The profile of deficits on the visual tasks may serve to differentiate Alzheimer's from Parkinson's dementia and may reflect selective orbitofrontal system lesions in the former.     

Effects of practice and preferred rate on perceived exertion,metabolic variables and movement control

One interesting feature of motor skill learning and control is our propensity to reduce the metabolic energy cost of achieving the task goal with practice and, if unconstrained, to adapt movements to task constraints using an energy-efficient preferred mode. This study investigated the effects of preferred rate and practice on metabolic variables, ratings of perceived exertion (RPE) and movement control. Six healthy well-trained male volunteers with no experience of rowing undertook one session per day over 6 days on a Concept II rowing ergometer at a power output of 100 W at preferred stroke rate (PR) and then at experimenter imposed rates of +20% (PR+) and −20% (PR−) of preferred. Heart rate and RPE declined significantly over days and there was an associated but nonsignificant reduction in oxygen consumption. Heart rate, oxygen consumption and RPE were significantly lower when rowing at preferred rate and economy was significantly greater. There was a trend toward reduced variability in the rowing cycle duration over practice days but the effect was not significant. Cycle duration was significantly less variable in the PR− phase than in the PR and PR+ phases, the latter phases were equally variable. Overall the data provide support for the view that motor learning is associated with changes to movement control parameters that reflect increased economy of energy expenditure in achieving the task goal. In addition, preferred modes (here preferred rate) appear to be associated with more economical but not more stable performances than non-preferred. PsycINFO classification: 2330; 2560; 3720