Working memory and information processing speed were examined in children with myelomeningocele and shunted hydrocephalus using the Children's Paced Auditory Serial Addition Test (CHIPASAT). The CHIPASAT was administered to 31 children with myelomeningocele and shunted hydrocephalus and 27 healthy siblings, all between 8 and 15 years of age. They also completed other standardized measures of working memory and processing speed. Children with myelomeningocele made fewer correct responses than siblings, although the magnitude of group differences declined as the rate of stimulus presentation increased. Children with myelomeningocele also made fewer consecutive correct responses and were more likely to provide correct but nonconsecutive responses, suggesting that they responded in a way that circumvents the working memory demands of the task. Standardized measures of processing speed and working memory accounted for significant variance in CHIPASAT performance after controlling for age, group membership, math skill, and general intellectual functioning. The results indicate that children with myelomeningocele and shunted hydrocephalus display deficits in working memory and information processing speed, and suggest that the CHIPASAT may provide a valid measure of these skills. (JINS, 2006, 12, 305–313.)

The title of each session is linked to its abstract in the Table of Contents included at the start of the PDF file. Readers wishing to view a particular abstract can select the appropriate session title in the Table of Contents.

The contribution of neurologic, genetic, and demographic variables to decline in cognition was examined in 70 early- to mid-stage patients with Huntington's disease (HD) using random effects modeling. Study participants were followed prospectively at baseline and at four annual reevaluations. Only modest decline was noted on most neuropsychological variables. Neurologic dysfunction, assessed using the Quantified Neurologic Examination (QNE), proved to be the strongest predictor of cognitive decline. While significantly predictive of more rapid decline in neurologic functioning, CAG repeat length was not generally related to cognitive decline after adjusting for QNE, with the exception of performance on a single test of visual scanning and psychomotor speed (i.e., Trail Making Test, Part A). We propose that CAG repeat length is more closely linked with changes in basal ganglia that predominate in early- to mid-stage HD than with cortical degeneration seen later in disease progression. Such a relationship would explain the predictive value that CAG repeat length plays in changes associated with automatic motor response programs (e.g., QNE and Trail Making Test, Part A) but not in dysfunction on tasks requiring higher-order processing. (JINS, 2006, 12, 445–454.)

Previous fMRI research has found altered brain response after total sleep deprivation (TSD), with TSD effects moderated by task difficulty. Specific models of the impact of sleep deprivation and task difficulty on brain response have yet to be developed. Differences in networks of fMRI measured brain response during verbal encoding in sleep deprived and well-rested individuals were examined with structural equation modeling (SEM). During fMRI scanning, 23 healthy volunteers memorized words either easy or difficult to recall, 12 (well-rested) and 36 hours (sleep deprived) after awaking. A priori models that linked specified regions of interest were evaluated, with the focus on the extent to which two left parietal regions interacted with the left inferior frontal gyrus (Model 1) or with the right inferior frontal gyrus (Model 2). Task difficulty, not TSD, determined which model fit the brain response data; Model 2 fit best for hard words before and after TSD, whereas Model 1 fit best for easy words. TSD altered the patterns of interaction within each of the best fitting models: prefrontal interactions with the left inferior parietal lobe were diminished and intra-parietal interactions increased. Sleep deprivation and item difficulty produce different effects on brain networks involved in verbal learning. (JINS, 2006, 12, 591–597.)

The clock drawing test (CDT) is a widely used cognitive screening test. It is useful in identifying focal lesions and cognitive deficits in dementia groups. Lately, several studies attempted its use to differentiate between dementia subtypes. Although many studies have examined the CDT in dementia populations, research into the use of clock drawing in frontotemporal dementia (FTD) is limited. We examined quantitative (global) and qualitative (specific error type) differences on the CDT between FTD (n = 36) and Alzheimer's disease (AD; n = 25) patients and controls without dementia (n = 25). Results showed significantly lower overall scores in the dementia groups compared to the control group, whereas FTD patients scored significantly higher than the AD group. On qualitative analysis, the FTD group had fewer stimulus bound responses, conceptual deficits, and spatial or planning errors compared to the AD group. In conclusion, both global and error analysis of the CDT helped discriminate the FTD group from controls and AD patients. (JINS, 2006, 12, 159–165.)

In humans, the neural circuitry underlying facial expressions differs, depending on whether facial expressions are spontaneously (i.e., limbic, subcortical) or voluntarily initiated (i.e., frontal cortex). Previous investigators have suggested that the “masked face” of Parkinson's disease involves spontaneous, but not intentional, facial expressions. In contrast, we hypothesized that intentional facial expressions may be slowed (bradykinetic) and involve less movement, in much the same way that other intentional movements are affected by Parkinson's disease. To test this hypothesis, we used sophisticated computer imaging techniques to quantify dynamic facial movement. Relative to controls, Parkinson patients had reduced facial movement (entropy) and were significantly slowed in reaching a peak expression (i.e., bradykinesia). These findings are consistent with the view that the basal ganglia play a role in affecting intentional facial movements. This possibly occurs because of diminished efficiency and/or activation of face representation areas in the frontal cortical regions (i.e., motor, premotor, and supplementary motor area) or because of movement-based suppression secondary to dopaminergic reduction in frontostriatal pathways. Taken together, the characterization of Parkinson's disease as a model system for the neuroanatomic dissociation between voluntary and spontaneous expressions may be unjustified. (JINS, 2006, 12, 765–773.)

Response bias reflects the decision rule an individual uses when faced with uncertainty on recognition memory tasks. Recent studies indicate frontal regions may mediate response bias performance. One theory of aging also implicates frontal lobe contributions in age-related cognitive changes. This suggests that frontal lobe changes may mediate response bias in older adults. Consistent with this frontal aging hypothesis, we predicted that response bias would become more liberal with age. Methods: Participants were 181 younger (30–49) and 112 older normal adults (75+) that were part of the California Verbal Learning Test-second edition (CVLT-2) normative sample (total n = 1078). We used parametric measures of discriminability and response bias provided by the CVLT-2 scoring program. Groups were similar in IQ and education. Multi-level regression models were created to examine the effects of moderating variables. The interaction between age and age group significantly predicted response bias. Post hoc analysis indicated that increasing age was associated with more liberal bias in the older but not in the younger group. In the light of reported relationships between frontal regions and both aging and response bias, we hypothesize that frontal changes may be the underlying mechanism explaining the increase in liberal response bias with age. (JINS, 2006, 12, 1–7.)

Learning and performance on a ballistic task were investigated in children with spina bifida meningomyelocele (SBM), with either upper level spinal lesions (n = 21) or lower level spinal lesions (n = 81), and in typically developing controls (n = 35). Participants completed three phases (20 trials each) of an elbow goniometer task that required a ballistic arm movement to move a cursor to one of two target positions on a screen, including (1) an initial learning phase, (2) an adaptation phase with a gain change such that recalibration of the ballistic arm movement was required, and (3) a learning reactivation phase under the original gain condition. Initial error rate, asymptotic error rate, and learning rate did not differ significantly between the SBM and control groups. Relative to controls, the SBM group had reduced volumes in the cerebellar hemispheres and pericallosal gray matter (the region including the basal ganglia), although only the pericallosal gray matter was significantly correlated with motor adaptation. Congenital cerebellar dysmorphology is associated with preserved motor skill learning on voluntary, nonreflexive tasks in children with SBM, in whom the relative roles of the cerebellum and basal ganglia may differ from those in the adult brain. (JINS, 2006, 12, 598–608.)

Amnestic mild cognitive impairment (MCI) has been defined as a precursor to Alzheimer's disease (AD), although it is sometimes difficult to identify which persons with MCI will eventually convert to AD. We sought to predict MCI conversion to AD over a two-year follow-up period using baseline demographic and neuropsychological test data from 49 MCI patients. Using a stepwise discriminant function analysis with Dementia Rating Scale (DRS) Initiation/Perseveration and Wechsler Memory Scale, third edition (WMS-III) Visual Reproduction Percent Retention scores, we correctly classified 85.7% of the sample as either AD converters or MCI nonconverters, with 76.9% sensitivity and 88.9% specificity. Adding race, the presence of vascular risk factors, or cholinesterase inhibitor use to the analysis did not greatly change the classification rates obtained with neuropsychological test data. Examining neuropsychological test cutoff scores revealed that DRS Initiation/Perseveration scores below 37 and Visual Reproduction Percent Retention scores below 26% correctly identified AD converters with 76.9% sensitivity and 91.7% specificity. These results demonstrate that commonly administered neuropsychological tests identify persons with MCI at baseline who are at risk for conversion to AD within 1–2 years. Such methods could aid in identifying MCI patients who might benefit from early treatment, in providing prognostic information to patients, and identifying potential clinical trial participants. (JINS, 2006, 12, 166–175.)

Trajectories of saccadic eye movements can be modulated by the presence of a competing visual distractor. It is proposed that the superior colliculus (SC) controls the initial deviation through competitive lateral interactions. Given the ramifications of connections between basal ganglia (BG) thalamo-cortical circuitry and the SC, it was anticipated that this modulation would be differentially effected in those with Huntington's disease, which in its early stages is primarily a disorder of the BG. Horizontal deviation was determined for exogenously driven and endogenously driven vertical saccades in the presence of peripheral distractors. For neurologically healthy participants, the initial trajectories of both saccade types curved away from distractor locations, as predicted. However, for HD participants exogenous saccades consistently deviated leftwards, irrespective of distractor location. Endogenous saccades also revealed anomalous horizontal deviation, with significant leftward deviation evident for saccades directed upward and significant rightward deviation for saccades directed downward. Further, both groups generated a comparable proportion of erroneous responses to distractor stimuli, but only neurologically healthy participants demonstrated a response time advantage for compatible target/distractor presentation. These results suggest anomalous regulation of distractor-related activity in HD. (JINS, 2006, 12, 455–464.)

Impaired imitation of skilled gestures is commonly reported in autism. Questions, however, remain as to whether impaired imitation is associated with a more generalized deficit in performance of gestures consistent with a dyspraxia and whether the pattern of errors differs from that observed in typically developing children. To address these questions, praxis in 21 high-functioning children with autism spectrum disorders (ASD) was compared with 24 typically developing controls using a traditional approach in which performance was evaluated through detailed examination of error types. Children with ASD produced significantly fewer correct responses not only during Gesture to Imitation, but also during Gesture to Command and with Tool Use. The pattern of errors in ASD was similar to that of controls with spatial errors being most common in both groups; however, body-part-for-tool errors were more common in children with ASD, suggesting dyspraxia is not entirely attributable to motor deficits. The findings suggest that autism is associated with a generalized praxis deficit, rather than a deficit specific to imitation. In a developmental disorder such as autism, the findings may reflect abnormalities in frontal/parietal–subcortical circuits important for acquisition (i.e., learning) of sensory representations of movement and/or the motor sequence programs necessary to execute them. (JINS, 2006, 12, 314–326.)

The aim of this investigation was to assess deficits in prospective remembering following chronic traumatic brain injuries (TBI), under conditions of high and low distraction. We constructed a virtual shopping precinct from photographs, sounds, and video segments linked together. The street was divided into halves, a low distraction zone and a high distraction zone (with increased visual and auditory noise). Twenty persons with TBI (7 severe, 7 very severe, 6 extremely severe) and 20 matched controls completed ongoing and prospective memory tasks while “walking” along the street. In the ongoing task, participants were given ten errands to complete with a checklist accessible at any time. The prospective component required responding to three targets that appeared repeatedly. As predicted, the TBI group performed both the ongoing and the prospective components of the street task poorly compared with the controls and was more affected by distractions. The results suggest that the real-life deficits in memory skills reported by persons with TBI may become more apparent when remembering engages executive processes and that computer simulations can be used to construct sensitive measures of practical memory abilities. (JINS, 2006, 12, 8–16.)

Studies of patients with brain damage, as well as studies with normal subjects have revealed that the right hemisphere is important for recognizing emotions expressed by faces and prosody. It is unclear, however, if the knowledge needed to perform recognition of emotional stimuli is organized by modality or by the type of emotion. Thus, the purpose of this study is to assess these alternative a priori hypotheses. The participants of this study were 30 stroke patients with right hemisphere damage (RHD) and 31 normal controls (NC). Subjects were assessed with the Polish adaptation of the Right Hemisphere Language Battery of Bryan and the Facial Affect Recognition Test based on work of Ekman and Friesen. RHD participants were significantly impaired on both emotional tasks. Whereas on the visual-faces task the RHD subjects recognized happiness better than anger or sadness, the reverse dissociation was found in the auditory-prosody test. These results confirm prior studies demonstrating the role of the right hemisphere in understanding facial and prosodic emotional expressions. These results also suggest that the representations needed to recognize these emotional stimuli are organized by modality (prosodic-echoic and facial-eidetic) and that some modality specific features are more impaired than others. (JINS, 2006, 12, 774–781.)

The title of each session is linked to its abstract in the Table of Contents included at the start of the PDF file. Readers wishing to view a particular abstract can select the appropriate session title in the Table of Contents.

This study directly compared how well Korsakoff patients can process spatial and temporal order information in memory under conditions that included presentation of only a single feature (i.e., temporal or spatial information), combined spatiotemporal presentation, and combined spatiotemporal order recall. Korsakoff patients were found to suffer comparable spatial and temporal order recall deficits. Of interest, recall of a single feature was the same when only spatial or temporal information was presented compared to conditions that included combined spatiotemporal presentation and recall. In contrast, control participants performed worse when they have to recall both spatial and temporal order compared to when they have to recall only one of these features. These findings together indicate that spatial and temporal information are not automatically integrated. Korsakoff patients have profound problems in coding the feature at hand. Moreover, their lower recall of both features at the same time suggests that Korsakoff patients are impaired in binding different contextual attributes together in memory. (JINS, 2006, 12, 327–336.)

To elucidate the role of visual and nonvisual attribute knowledge on visual object identification, we present data from three patients, each with visual object identification impairments as a result of different etiologies. Patients were shown novel computer-generated shapes paired with different labels referencing known entities. On test trials they were shown the novel shapes alone and had to identify them by generating the label with which they were formerly paired. In all conditions the same triad of computer-generated shapes were used. In one condition, the labels (banjo, guitar, violin) referenced entities that were both visually similar and similar in terms of their nonvisual attributes within semantics. In separate conditions we used labels (e.g., spike, straw, pencil or snorkel, cane, crowbar) that referenced entities that were similar in terms of their visual attributes but were dissimilar in terms of their nonvisual attributes. The results revealed that nonvisual attribute information profoundly influenced visual object identification. Our patients performed significantly better when attempting to identify shape triads whose labels referenced objects with distinct nonvisual attributes versus shape triads whose labels referenced objects with similar nonvisual attributes. We conclude that the nonvisual aspects of meaning must be taken into consideration when assessing visual object identification impairments. (JINS, 2006, 12, 176–183.)

This study assessed whether verbal memory performance indexed by the California Verbal Learning Test (CVLT) can organize and reduce the heterogeneity of schizophrenia. The temporal stability, cognitive and clinical validity of: (a) a putatively cortical-subcortical-normative typology derived from dementia patients' scores on the CVLT and (b) a memory performance dichotomy based on a psychometric criterion and 1 CVLT summary score were evaluated. These memory subtypes were examined in 102 schizophrenia patients, 55 of whom were assessed again 3 years later. The results indicate that both methods yield potentially valuable illness distinctions on a cross-sectional basis, but fail to show truly trait-like properties. Furthermore, the evidence favors the validity of a parsimonious dichotomy over a more complex dementia-based typology. (JINS, 2006, 12, 782–791.)

The title of each session is linked to its abstract in the Table of Contents included at the start of the PDF file. Readers wishing to view a particular abstract can select the appropriate session title in the Table of Contents.