This study utilised a finger force task to investigate the influence of attention and age on the occurrence of motor overflow in the form of mirror movements in neurologically intact adults. Forty right-handed participants were recruited from three age groups: 20–30 years, 40–50 years, and 60–70 years. Participants were required to maintain a target force using both their index and middle fingers, representing 50% of their maximum strength capacity for that hand. Attention was directed to a hand by activating a bone conduction vibrator attached to the small finger of that hand. Based on Cabeza's (2002) model of hemispheric asymmetry reduction in older adults, it was hypothesised that mirror movements would increase with age. Furthermore, it was expected that when the attentional demands of the task were increased, motor overflow occurrence would be exacerbated for the older adult group. The results obtained provide support for the model, and qualified support for the hypothesis that increasing the attentional demands of a task results in greater motor overflow. It is proposed that the association between mirror movements and age observed in this study may result from an age-related increase in bihemispheric activation that occurs in older adults, who, unlike younger adults, benefit from bihemispheric processing for task performance. (JINS, 2005, 11, 855–862.)

Metaphors are a fundamental aspect of human cognition. The major neuropsychological hypothesis that metaphoric processing relies primarily on the right hemisphere is not confirmed consistently. We propose ways to advance our understanding of the neuropsychology of metaphor that go beyond simple laterality. Neuropsychological studies need to more carefully control confounding lexical and sentential factors, and consider the role of different parts of speech as they are extended metaphorically. They need to incorporate recent theoretical frameworks such as the career of metaphor theory, and address factors such as novelty. We also advocate the use of new methods such as voxel-based lesion-symptom mapping, which permits precise and formal tests of hypotheses correlating behavior with lesions sites. Finally, we outline a plausible model for the neural basis of metaphor. (JINS, 2010, 16, 1–5.)

We hypothesized that patterns of sustained attention performance in bipolar disorder were consistent with processing efficiency theory—a theory of the relationship between central processing capacity and performance. We predicted (1) sustained attention deficits during mania because symptoms interfere with limited-capacity executive control processes resulting in decreased performance effectiveness; and (2) decreased processing efficiency during euthymia, as indicated by speed/accuracy tradeoffs, consistent with a stable phenotypic abnormality. Twenty-five manic bipolar, 23 euthymic bipolar, and 28 healthy comparison participants were compared on a continuous performance task and administered symptom-rating scales. The manic group was significantly impaired on overall perceptual sensitivity and demonstrated a significant linear decrease in performance over time, consistent with impaired sustained attention. The euthymic group evidenced significantly slower overall hit reaction time (RT), but when RT was controlled they performed similarly to the healthy group over time. Two discriminant functions combined to separate the groups on manic symptom severity and on-task effort/strategy use. These findings are consistent with processing efficiency theory. They suggest that euthymic patients sustain attention through effortful control at the expense of processing efficiency, while acute mania reduces the capacity for control and impairs sustained attention. Problems with processing efficiency are viewed as trait characteristics of bipolar disorder that may be overlooked by traditional error-based assessments. (JINS, 2005, 11, 49–57.)

Behavioral dysregulation is a common and detrimental consequence of traumatic brain injury (TBI) in children that contributes to poor academic achievement and deficits in social development. Unfortunately, behavioral dysregulation is difficult to predict from either injury severity or early neuropsychological evaluation. The uncinate fasciculus (UF) connects orbitofrontal and anterior temporal lobes, which are commonly implicated in emotional and behavioral regulation. Using probabilistic diffusion tensor tractography (DTT), we examined the relationship between the integrity of the UF 3 months post-injury and ratings of executive functions 12 months post-injury in children with moderate to severe TBI and a comparison group with orthopedic injuries. As expected, fractional anisotropy of the UF was lower in the TBI group relative to the orthopedic injury group. DTT metrics from the UF served as a biomarker and predicted ratings of emotional and behavior regulation, but not metacognition. In contrast, the Glasgow Coma Scale score was not related to either UF integrity or to executive function outcomes. Neuroanatomical biomarkers like the uncinate fasciculus may allow for early identification of behavioral problems and allow for investigation into the relationship of frontotemporal networks to brain-behavior relationships. (JINS, 2011, 17, 663–673)

Cognitive reserve (CR) has been proposed as a latent variable that can account for the frequent discrepancy between an individual's underlying level of brain pathology and their observed clinical outcome. A possible behavioral manifestation of CR is best strategy choice. Older adults have been shown to choose sub-optimal strategies for performing various tasks. The present study attempted to investigate whether greater levels of CR could predict greater strategy selection, particularly in older adults. A computational estimation task was administered to 20 healthy young adults (mean age = 24.7 ± 3.6; 20–31 years) and 18 healthy older adults (68.2 ± 4.5; 62–77 years) wherein participants needed to estimate the product of two two-digit numbers by using one of two strategies. The results revealed an effect of age group on strategy choice and supported the hypothesis that CR is associated with increased strategy selection abilities. (JINS, 2013, 19, 1–4)

Literature suggests that individuals with mild traumatic brain injury (mTBI) show subtle abnormalities in the cognitive control process of performance monitoring. The neural bases of performance monitoring can be measured using the error-related negaitivity (ERN) and post-error positivity (Pe) components of the scalp-recorded event-related potential (ERP). Thirty-six individuals with mTBI and 46 demographically similar controls completed a modified color-naming Stroop task while ERPs were recorded. Separate repeated-measures analyses of variance were used to examine the behavioral (response times [RT] and error rates) and ERP (ERN and Pe amplitudes) indices of performance monitoring. Both groups showed slower RTs and increased error rates on incongruent trials relative to congruent trials. Likewise, both groups showed more negative ERN and more positive Pe amplitude to error trials relative to correct trials. Notably, there were no significant main effects or interactions of group for behavioral and ERP measures. Subgroup and correlational analyses with post-concussive symptoms and indices of injury severity were also not significant. Findings suggest comparable performance to non-injured individuals in some aspects of cognitive control in this sample. Neuropsychological implications and comparison with other cognitive control component processes in individuals with TBI are provided. (JINS, 2012, 18, 323–333)

Age-related memory changes are highly varied and heterogeneous. The study examined the rate of decline in verbal episodic memory as a function of education level, auditory attention span and verbal working memory capacity, and diagnosis of amnestic mild cognitive impairment (a-MCI). Data were available on a community sample of 653 adults aged 17–86 years and 70 patients with a-MCI recruited from eight broad geographic areas in Greece and Cyprus. Measures of auditory attention span and working memory capacity (digits forward and backward) and verbal episodic memory (Auditory Verbal Learning Test [AVLT]) were used. Moderated mediation regressions on data from the community sample did not reveal significant effects of education level on the rate of age-related decline in AVLT indices. The presence of a-MCI was a significant moderator of the direct effect of Age on both immediate and delayed episodic memory indices. The rate of age-related decline in verbal episodic memory is normally mediated by working memory capacity. Moreover, in persons who display poor episodic memory capacity (a-MCI group), age-related memory decline is expected to advance more rapidly for those who also display relatively poor verbal working memory capacity. (JINS, 2014, 20, 1–14)

Systematic cognitive training produces long-term improvement in cognitive function and less difficulty in performing activities of daily living. We examined whether cognitive training was associated with reduced rate of incident dementia. Participants were from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (n = 2,802). Incident dementia was defined using a combination of interview- and performance-based methods. Survival analysis was used to determine if ACTIVE treatment affected the rate of incident dementia during 5 years of follow-up. A total of 189 participants met criteria for incident dementia. Baseline factors predictive of incident dementia were older age, male gender, African American race, fewer years of education, relationship other than married, no alcohol use, worse MMSE, worse SF-36 physical functioning, higher depressive symptomatology, diabetes, and stroke (all p < .05). A multivariable model with significant predictors of incident dementia and training group revealed that cognitive training was not associated with a lower rate of incident dementia. Cognitive training did not affect rates of incident dementia after 5 years of follow-up. Longer follow-up or enhanced training may be needed to fully explore the preventive capacity of cognitive training in forestalling onset of dementia. (JINS, 2012, 18, 1–9)

There is equivocal evidence whether or not patients with obsessive–compulsive disorder (OCD) share an attentional bias for concern-related material and if so, whether this reflects hypervigilance towards or problems to disengage from disorder-related material. In a recent study, we failed to detect an attentional bias in OCD patients using an emotional variant of the inhibition of return (IOR) paradigm containing OCD-relevant and neutral words. We reinvestigated the research question with a more stringent design that addressed potential moderators. A new IOR paradigm was set up using visual stimuli. Forty-two OCD patients and 31 healthy controls were presented with neutral (e.g., cup), anxiety-relevant (e.g., shark), checking-relevant (e.g., broken door), and washing-relevant (e.g., dirty toilet) cue pictures at one of two possible locations. Following a short or long interval sensitive to automatic versus controlled processes, a simple target stimulus appeared at either the cued or the uncued location. OCD patients responded significantly slower to targets that were preceded by an OCD-relevant cue. Results lend support to the claim that OCD patients share a processing abnormality for concern-related visual material. (JINS, 2009, 15, 365–371.)

Social cognition and learning potential have been proposed as mediating variables between neurocognition and functional outcome in schizophrenia. The present study examined this relation in a schizophrenia group (N = 26) with normal IQ. Neurocognition was measured with a composite score from tests of verbal learning, psychomotor speed, and executive functioning. Functional outcome was defined as social problem-solving skills and assessed with a role-play test. Social cognition was indexed by tests of visual and auditory emotion perception; and learning potential by estimating a gain score using a triple administration of the WCST. Neurocognition was confirmed to be a strong predictor of social problem-solving, and emotion perception was related to both neurocognition and social problem-solving. When controlling for emotion perception, the association between neurocognition and social problem-solving was weakened, implying a mediating role of emotion perception. Learning potential was not significantly related to neurocognition or social problem-solving, and thus not found to mediate the studied relation. In conclusion, our study indicates that emotion perception is a mediator between neurocognition and functional outcome as assessed with a social problem-solving task and thus a key factor in understanding functional outcome of schizophrenia. (JINS, 2008, 14, 279–288.)

Neuropsychological test interpretation has relied on pre- and postmorbid comparisons, as exemplified by the use of demographically adjusted normative data. We argue that, when the assessment goal is to predict real-world functioning, this interpretive method should be supplemented by “absolute” scores. Such scores are derived from comparisons with the general healthy adult population (i.e., demographically unadjusted normative data) and reflect examinees’ current ability, that is, the interaction between premorbid and injury/disease-related factors. In support of this view, we found that substantial discrepancies between demographically adjusted and absolute scores were common in a traumatic brain injury sample, especially in participants with certain demographic profiles. Absolute scores predicted selected measures of functional outcome better than demographically adjusted scores and also classified participants’ functional status more accurately, to the extent that these scores diverged. In conclusion, the ecological validity of neuropsychological tests may be improved by the consideration of absolute scores. (JINS, 2009, 15, 94–102.)

The aim of this study was to evaluate attention difficulties in a contemporary geographic cohort of adolescents born extremely preterm (EP, <28 weeks’ gestation) or extremely low birth weight (ELBW, birth weight <1000 g). The EP/ELBW group included 228 adolescents (mean age = 17.0 years) born in Victoria, Australia in 1991 and 1992. The control group were 166 adolescents (mean age = 17.4 years) born of normal birth weight (birth weight >2499 g) who were recruited in the newborn period and matched to the EP/ELBW group on date of birth, gender, language spoken and health insurance status. Participants were assessed on measures of selective, sustained, and executive (shift and divided) attention, and parents and participants completed behavioral reports. The EP/ELBW group performed more poorly across tests of selective and executive attention, had greater rates of clinically significant difficulties compared with the control group, and also had greater behavioral attention problems as reported by parents. Neonatal risk factors were weakly associated with attention outcomes. In conclusion, higher rates of attention impairments are observed in individuals born EP/ELBW well into adolescence and may have consequences for their transition to adulthood. (JINS, 2013, 19, 1–12)

Executive control of learning and memory was examined in children with bilateral spastic cerebral palsy (SCP). We hypothesized that SCP-related brain damage would disrupt executive but not associative aspects of learning and memory. To test this hypothesis, the California Verbal Learning Test–Children's Version was administered to 16 children with bilateral SCP and 19 control children ranging from 6 to 18 years of age. Controlling for general verbal ability, the groups did not differ in initial learning and retention of information over time, suggesting that associative learning and memory processes subserved by medial temporal brain regions were relatively intact in children with SCP. In contrast, impairments in learning over repeated trials, strategic processing, and inhibition in the SCP group pointed to disruptions in prefrontally-mediated executive aspects of learning and memory. The inhibitory deficit was more pronounced in younger children with SCP, suggesting a developmental delay in this ability. (JINS, 2005, 11, 920–924.)

A triplet repeat (CAG) expansion mutation in the huntingtin gene on chromosome 4 is responsible for Huntington's disease (HD). Presymptomatic genetic testing for this mutation has identified clinically normal persons who are virtually certain to develop this dementing illness if they live a normal lifespan. The present study sought to determine whether these “mutation-positive” persons have impairments in cognitive functioning. Seventy-five mutation-positive persons did not differ from 128 mutation-negative persons on tests selected for their sensitivity to early-stage HD. Interestingly, however, those with the mutation viewed themselves as more likely to develop HD than did those without the mutation. Among mutation-positive subjects, having a longer CAG repeat mutation was likewise not associated with cognitive impairment. However, being closer to estimated disease onset (a product of repeat length and parent's age at onset) was associated with selected cognitive impairments. When viewed in light of previous studies showing atrophy of the caudate nucleus and putamen in mutation-carriers who are close to onset but not those far from onset, these results suggest that subtle changes in brain and behavior may be detected shortly before subjects with the HD mutation develop sufficient signs and symptoms for diagnosis. Conceptual and methodological problems associated with the search for presymptomatic cognitive and behavioral indicators of dementing illness are discussed. (JINS, 2002, 8, 918–924.)

Although the development of Attention Deficit Hyperactivity Disorder (ADHD) after traumatic brain injury (TBI) has been described, it is unknown whether children with TBI and ADHD have greater neuropsychological impairments than children with TBI alone. This study examines attention, executive functioning, and memory in children with TBI-only and TBI + ADHD. Caregivers of 82 children with severe TBI completed structured psychiatric interviews at enrollment to diagnose premorbid ADHD and one-year after injury to diagnose post-injury ADHD. Children underwent neuropsychological testing one year after injury. One memory measure significantly differentiated children with TBI-only from children with newly developed ADHD [secondary ADHD (S-ADHD)] and those with premorbid ADHD that persisted after injury [persisting ADHD (P-ADHD)]. Compared with the TBI-only group, children with TBI + ADHD had worse performance on measures of attention, executive functioning, and memory. Results reveal that in children with severe TBI, the behavioral diagnosis of ADHD is associated with more difficulty in attention, executive functioning, and memory. Additionally, results suggest greater deficits in memory skills in the S-ADHD group compared with the P-ADHD group. Although findings provide preliminary support for distinguishing P-ADHD from S-ADHD, further research is needed to investigate neuropsychological differences between these subgroups of children with severe TBI. (JINS, 2005, 11, 645–653.)

We investigated whether (1) cognitive deficits are present among persons who will be diagnosed with vascular dementia (VaD) 3 years later, and (2) the pattern of such deficits is similar to that observed in preclinical Alzheimer's disease (AD). The VaD diagnosis was a diagnosis of post-stroke dementia. Population-based samples of 15 incident VaD cases, 43 incident AD cases, and 149 normal controls were compared on tests of episodic and short-term memory, verbal fluency, and visuospatial skill. Both dementia groups showed preclinical impairment relative controls on tasks assessing episodic memory 3 years before diagnosis, and there were no differences between these groups on any cognitive measure. The existence of a preclinical phase in the present VaD cases suggests that circulatory disturbance may affect cognitive performance before the occurrence of stroke that leads to clinical VaD. These results extend previous findings of similar patterns of cognitive deficits in the early clinical phases of AD and VaD to the preclinical phases of these diseases. (JINS, 2004, 10, 382–391.)

Reliable neuropsychological markers of right temporal integrity have proven elusive. Specifically it is unclear whether figural and spatial aspects of visual memory are differentially affected by right temporal lobe epilepsy (TLE) and subsequent resection. To investigate this we used the modified Rey Complex Figure (RCF) scoring system devised by Brier et al. (1996) to obtain separate indices of figural and spatial memory in TLE surgery candidates. We extended on their study by examining presurgical performance and change following right and left temporal lobectomy (RATL, n = 38, LATL, n = 42) in individuals from a cross-institutional sample with and without hippocampal sclerosis (HS+/HS−). Contrary to expectation neither figural nor spatial RCF recall were differentially sensitive to RTLE, right HS, or subsequent resection. Presurgically, laterality effects on both figural and spatial memory indices were not found although HS− individuals significantly outperformed HS+ individuals on both measures. Following surgery the largest decrements in both figural and spatial recall were observed among LATL HS− participants. We concluded that RCF recall is a poor marker of right temporal lobe function and suggest it may be a “surrogate” measure of left temporal lobe function possibly due to the verbalizability of many of its components. (JINS, 2007, 13, 664–671.)

This study was designed to examine the patterns of apraxic disturbances and the relationships between action knowledge and other measures of semantic knowledge about objects in 10 well-characterized Alzheimer's disease (AD) patients. Five tasks were used to assess components of action knowledge (action–tool relationships, pantomime recognition, and sequential organization of action) and praxis execution (actual use, pantomiming) according to the cognitive model of praxis. Three tasks (verbal comprehension, naming, and a visual semantic matching task) were used to assess verbal–visual semantics. Considering patterns of apraxia first, conceptual apraxia was found in 9 out of the 10 AD patients, suggesting that it is a common feature even in the early stages of AD. Second, we found partly parallel deficits in tests of action-semantic and verbal–visual semantic knowledge in 9 AD patients. Impaired action knowledge was found only in patients with a semantic language deficit. These findings provide no evidence that “action semantics” may be separated from other semantic information. Our results support the view of a unitary semantic system, given that the representations of action-semantic and other semantic knowledge of objects are often simultaneously disrupted in AD. (JINS, 2000, 6, 693–703.)

The objective of this study is to systematically investigate sleep following moderate–severe pediatric traumatic brain injury (TBI). School-aged children with moderate–severe TBI identified via hospital records were invited to participate, along with a school-age sibling. Subjective reports and objective actigraphy correlates of sleep were recorded: Children's Sleep Habits Questionnaire (CSHQ), Sleep Self-Report questionnaire (SSR), and 5-night actigraphy. TBI participants (n = 15) and their siblings (n = 15) participated. Significantly more sleep problems were parent-reported (CSHQ: p = 0.003; d = 1.57), self-reported (SSR: p = 0.003; d = 1.40), and actigraph-recorded in the TBI group (sleep efficiency: p = 0.003; d = 1.23; sleep latency: p = 0.018; d = 0.94). There was no evidence of circadian rhythm disorders, and daytime napping was not prevalent. Moderate–severe pediatric TBI was associated with sleep inefficiency in the form of sleep onset and maintenance problems. This preliminary study indicates that clinicians should be aware of sleep difficulties following pediatric TBI, and their potential associations with cognitive and behavioral problems in a group already at educational and psychosocial risk. (JINS, 2013, 19, 1–6)

On the basis of what is known about the neural circuitry essential or normally involved in eyeblink classical conditioning (EBCC), the pattern of neurodegeneration in Huntington's disease (HD) would not appear to interfere with this type of learning. HD causes severe atrophy of the basal ganglia and thinning and shrinkage of the cerebral cortex. However, the hippocampus and hippocampal cholinergic system remain relatively intact, as does the cerebellum. Because the brain circuitry engaged in EBCC is neither lesioned nor disrupted in HD, it was predicted that HD patients would perform like normal control subjects in the 400-ms delay EBCC paradigm. Performance of seven patients with HD was compared to age-matched normals, with two control subjects matched to each HD patient. There were no differences in production of conditioned responses (CRs) between HD patients and normal control subjects, but the timing of the CR was abnormal in HD. Comparisons of HD patients to patients with other neurodegenerative diseases (probable Alzheimer's disease (PAD) and Down syndrome (DS) over the age of 35 with presumed Alzheimer-like neuropathology) and to patients with cerebellar lesions demonstrated significantly better EBCC performance in HD. Results suggest that the ability to acquire CRs is normal in HD, but the striatum may have some role in optimizing the timing of the CR. (JINS, 1996, 2, 323–334.)