Specific Cognitive Impairments Research Articles

What matters in white matter dementia?

Dementia studies has primarily focused on disorders of the cerebral cortex and subcortical gray matter, what originated the concepts of cortical and subcortical dementias respectively. Dementia related mainly with cerebral white matter have received less attention. We present five different cases, each one illustrative of a dementia subtype that could be assigned under the category of ‘white matter dementia’: CADASIL, progressive subcortical gliosis, progressive multifocal leucoencephalopathy, normopressure hydrocephalus and brain injury. Besides that, recent clinical and scientific literature on white matter dementia was reviewed. The composition of exuberant psychiatric symptoms and personality changes (mainly apathy, but also desinhibition) with neurological signs (pyramidal alone or associated with extrapyramidal signs, ataxia and urinary incontinence) and with specific cognitive impairment (mentioned above), should rise strongly the possibility of a white-matter dementia, instead of a cortical or subcortical form of dementia.

Cognitive impairment patterns in Parkinson’s disease with visual hallucinations

Objectives We investigated the role of stage of disease, motor status and dopaminergic treatment in cognitive impairment of Parkinson’s disease (PD) patients with visual hallucination (VH) and the presence of specific cognitive impairment patterns. Method We compared 33 PD patients with VH (group 1) with 30 PD patients without VH (group 2) with regard to demographic characteristics and neuropsychological test scores. Results The group with VH demonstrated significantly worse Short Test of Mental Status scores; the cognitive impairment pattern presented in the form of frontal dysfunction and memory deterioration. There were significant differences in Stroop duration/error, verbal fluency, Wechsler Memory Scale and Sozel Bellek Surecleri Test (a Turkish verbal learning test) scores. Conclusion In PD patients with VH the main pattern of cognitive impairment is frontal dysfunction and memory deterioration. Because visual perceptive functions were not different between the two groups, such deterioration may not be a primary factor in the development of VH.

The Influence of Neuropsychological Functioning on Neuropsychiatric Problems in Dementia

Although much is known about the relationship between neuropsychiatric problems and the severity of cognitive impairments, relatively little is known about the association with specific cognitive impairments. The aim of this study was to determine whether specific cognitive impairments are predictive of neuropsychiatric problems. One hundred twenty-six patients were evaluated every 6 months for 2 years. In particular, a low level of language expression was related to higher levels of overall neuropsychiatric problems and to psychosis. Impairment of abstract reasoning was related to psychosis and aberrant motor behavior.

Abstracts from CyberTherapy 2006

The main characteristic of virtual reality (VR) dwells in carrying spatial information in an analogical mode preserving most of space-time dimensions and interaction modalities that humans usually have in natural contexts. According to this, the spatial nature of virtual environments revealed an advantageous opportunity for the evaluation of residual perceptual abilities and motor-explorative behaviours in patients with cognitive impairment. In particular, it has been suggested that VR can be effectively used to evaluate how cognitive impaired users, such as patients affected by visuo-spatial neglect, are able to explore and memorize the environment in which they are able to interact. Neglect patients present difficulties in attending to stimuli placed in the contralesional space (typically the left hemispace). Several kinds of task can be used to assess and to modulate neglect behavior. These tasks should address the whole range of cognitive domains in which the disorder could be manifested (perception and mental representation, personal/ extrapersonal space, navigation abilities). Since standard evaluation of neglect syndrome is mainly carried out using paper-based tests within the laboratory, the assessment of patient’s behavior impairments in everyday contexts tends to be overlooked. Drawing on these premises, we introduced a Vrsituated approach for the evaluation of neglect patient’s perceptive, memory, and explorative residual abilities in coping with daily contexts. We designed two virtual environments: a small-scale, closed environment within which neglect patients could position objects and navigate; and a large-scale, open one, which patients explored freely. The main goal of the first virtual environment provided is to evaluate patients’ ability in memorizing, recognizing, and replacing objects within all the field of vision. The main aim of the second one is to evaluate patients’ exploration strategies and to analyze their description of context they are engaged with. We tested the environments in four brain-damaged patients. They were requested to immersively explore the environments in order to memorize, replace, and recognize familiar objects. Patients included in the study were previously evaluated with “paper and pencil” neuropsychological assessment which revealed respectively a neglect syndrome, an overcome neglect, a right brain damage without neglect and frontal brain injury (with slight attentional neglect). Results showed that, compared with standard evaluation (that is mainly grounded on the detection and recognition of motionless target objects) patients’ interaction with virtual environments (in which target objects are situated in a dynamical scene) exhibited peculiar explorative behaviors, such as perseverations and/or right-side navigation tendencies, that could be addressed to their specific cognitive impairments. In addition, from a methodological point of view, the introduction of a VR-based assessment allowed us to deliver the complexity of stimulus challenges of naturalistic settings, as well as to monitor them in order to identify what constitute patients’ main troubles in managing daily activities.

Selective alexia and agraphia sparing numbers—a case study

We report a patient (MT) with a highly specific alexia affecting the identification of letters and words but not numbers. He shows a corresponding deficit in writing: his letter writing is impaired while number writing and written calculation is spared. He has no aphasia, no visuo-perceptual or -constructional difficulties, or other cognitive deficits. A similar pattern of performance has to our knowledge only been reported once before [Anderson, S. W., Damasio, A. R., & Damasio, H. (1990). Troubled letters but not numbers. Domain specific cognitive impairments following focal damage in frontal cortex. Brain, 113, 749–766]. This study shows that letter and number reading are dependent on dissociable processes. More interestingly, it points to a common mechanism subserving the perception and production of letters. We suggest that a deficit in a visuo-motor network containing knowledge of the physical shape of letters might explain the pattern of performance displayed by MT.

Neuropsychological Findings in Rolandic Epilepsy and Landau‐Kleffner Syndrome

In an attempt to correlate neuropsychological deficits and various neurophysiological aspects of focal epileptic activity in benign childhood epilepsy, we have reviewed the findings of a longitudinal group study of benign childhood epilepsy with centrotemporal spikes (BCECTS) and several case studies of continuous spike-waves during slow sleep syndrome (CSWS). We first distinguish the temporary neuropsychological impairments often observed in the natural history of BCECTS from the more long-lasting and more specific neuropsychological deficits associated with CSWS, of which the Landau-Kleffner syndrome (LKS) is the most studied clinical form. A series of metabolic findings from (18)FDG-PET studies in BCECTS and CSWS children have shown that specific cognitive impairment is related to increased glucose uptake in cortical areas restricted to the associative cortex coincident with the focus of spike-wave discharges. From recent functional neuroimaging data of three patients recovered from LKS, we address the issue of the pathophysiology of cognitive impairment persisting after complete recovery of epilepsy. Finally, we discuss the reliability of the study of mismatch negativity to address the issue of the early effect of interictal discharges in typical and atypical BCECTS on the auditory cortex and the development of speech processing essential to verbal learning.

Asymmetric Cerebral Embolic Load and Postoperative Cognitive Dysfunction in Cardiac Surgery

Background: The aim of the study was to determine the effects of asymmetric cerebral embolic load on cognitive functions. Methods: Thirty-six open heart surgery (OH) and 26 coronary artery bypass grafting (CABG) patients were evaluated by neuropsychological and transcranial Doppler tests. Results: OH was associated with a significantly larger microembolic load in comparison to CABG. In OH patients, the microembolic load at the left middle cerebral artery correlated with a verbal memory decline, whereas the microembolic load at the right middle cerebral artery correlated with a nonverbal memory deficit. CABG patients also showed a postoperative verbal memory decline which correlated with cardiopulmonary bypass length but not with microembolic load. Conclusion: Massive microembolic load during OH induces specific cognitive impairment in accordance to the brain region to which they are delivered. In atherosclerotic patients, the left temporal region is especially prone to perioperative ischemia.

Hemispheric lateralization of cognitive functions in children with centrotemporal spikes

We assessed the impact of unilateral epileptic foci in benign idiopathic partial epilepsy of childhood with rolandic discharges (BECT) on performance and hemispheric specialization in lateralized cognitive functions. Six children with BECT with a left-sided focus (BECT-L), 6 children with BECT with a right-sided focus (BECT-R), and 12 control children were tested in verbal, visual–spatial, and visual-attention tasks, with visual hemifield presentation. Children with BECT-R were impaired in the visual–spatial task relative to those with BECT-L, and the typical left-hemisphere (LH) advantage was not reported in the verbal task in children with BECT-L. Additionally, the classic global superiority effect was lacking in children with BECT-R, which may be due to impaired performance of the right hemisphere specialized in global (vs local)-level processing. These data argue for the deleterious effect of epileptic discharges per se on cognitive functions in the developing brain, and the decisive role of epileptic focus lateralization in specific cognitive impairments and hemispheric specialization.

Abnormal Brain Connectivity in Children After Early Severe Socioemotional Deprivation: A Diffusion Tensor Imaging Study

We previously reported that children who were subjected to early socioemotional deprivation in Romanian orphanages showed glucose hypometabolism in limbic and paralimbic structures, including the orbital frontal gyrus, infralimbic prefrontal cortex, hippocampus/amygdala, lateral temporal cortex, and the brainstem. The present study used diffusion tensor imaging tractography to examine the integrity of white matter tracts that connect these brain regions. Fractional anisotropy and apparent diffusion coefficient for uncinate fasciculus, stria terminalis, fornix, and cingulum were measured in 7 right-handed children (5 girls and 2 boys; mean age: 9.7 +/- 2.6 years) with a history of early severe socioemotional deprivation in Eastern European orphanages and compared with similar measurements in 7 right-handed normal children (4 girls and 3 boys; mean age: 10.7 +/- 2.8 years). Neuropsychological assessment of the orphans verified the relatively mild specific cognitive impairment and impulsivity consistent with previous studies of children who were adopted from Romanian orphanages. Fractional anisotropy values in the left uncinate fasciculus were decreased significantly in the early deprivation group compared with control subjects. Apparent diffusion coefficient values for the early deprivation group tended to be greater than that in control subjects in all of the tracts measured, without reaching statistical significance. Our study demonstrates in children who experienced socioemotional deprivation a structural change in the left uncinate fasciculus that partly may underlie the cognitive, socioemotional, and behavioral difficulties that commonly are observed in these children.

Élaboration d’un questionnaire sur les cognitions alimentaires

Élaboration d’un questionnaire sur les cognitions alimentaires

Correlations between Motor Performance and Cognitive Functions in Children Born < 1250 g at School Age

Very low birth weight born children manifest a higher prevalence of motor and cognitive impairments than term children. Seventy-four prospectively enrolled children born < 1250 g underwent testing of motor (Zurich neuromotor assessment ZNA: timed motor performances and associated movements) and cognitive functions (Kaufman-ABC) at age six years. Children with cerebral palsy or mental retardation were excluded. Adaptive motor tasks (pegboard and dynamic balance) and visuomotor cognitive functions were specifically impaired, and a distinct correlation pattern between motor and cognitive abilities was detected. The adaptive fine motor task (pegboard) correlated with visuomotor functions of the Kaufman-ABC ("triangles", r = 0.35; "matrix analogies", r = 0.39), while pure motor tasks of the ZNA (repetitive, alternating, and sequential movements) did not in spite of impaired motor performance. Timed motor performance below the 10th percentile correlated strongly with cognitive delay (IQ < 85: adaptive fine motor: OR 6.0 [95% CI] 4.7-7.3; adaptive gross motor: OR 7.0 [CI 5.6-8.4]; static balance: OR 9.6 [CI 8.2-11.0]). In conclusion, motor deficits in children born < 1250 g without severe disabilities correlate with specific cognitive impairments, in particular of the visuomotor domain. The correlation pattern may indicate specific dysfunction in visuomotor transformation, the intermediate process between visual-perceptual input and motor output. Early assessment of both motor and cognitive functions using standardized assessment tools is important to determine the extent and combination of specific developmental disturbances and to tailor therapeutic intervention.

ASSOCIATION BETWEEN ERP-WAVEFORMS IN A GAMBLING TASK AND ANTENATAL MATERNAL ANXIETY: ADOLESCENTS OF ANXIOUS MOTHERS SHOW DIFFERENT FRONTAL LOBE FUNCTIONING

Objectives: Negative emotions experienced by the mother during pregnancy are reported to be negatively associated with the development of the child. Associations were found with emotional, behavioral and recently also with cognitive development. The aim of the present study was to psychophysiologically extend previous findings of specific cognitive impairments in adolescents of mothers who experienced high levels of anxiety during their pregnancy.

Specific cognitive deficits and differential domains of social functioning impairment in schizophrenia

There is considerable inconsistency in findings regarding the relationship between specific cognitive deficits and social impairment in patients with schizophrenia. This inconsistency may relate to variability across studies in how social functioning is measured and preliminary evidence suggests that different indices of social functioning (e.g., laboratory test, community assessment) may have different cognitive correlates. The present study examined this issue by evaluating the relationships between cognitive deficits (including social cognitive deficits), role-play test performance, and community social functioning in 28 inpatients with schizophrenia. We expected the two measures of social functioning to have only modest convergence with each other. Moreover, informed by the literature on cognitive functioning in schizophrenia, we identified specific cognitive processes that were hypothesized to be associated with role-play performance (delayed verbal memory and attentional vigilance) and social functioning in the community (delayed verbal memory and executive functioning). As expected, the two measures of social functioning were modestly correlated with each other. Community social functioning was associated with a relatively constrained pattern of cognitive deficits and received a significant contribution (Δ r 2 = 0.24) from specific cognitive processes beyond that of general cognitive functioning and symptom severity. In contrast to our hypotheses, role-play test performance was associated with a wide range of cognitive impairments and received little contribution from the specific cognitive processes beyond the effects of general cognitive functioning. Community social functioning, but not role-play test performance, was significantly associated with social cognition. These findings highlight the importance of conceptualizing social functioning as a multidimensional construct for schizophrenia research.

High-LET Radiation Induces Inflammation and Persistent Changes in Markers of Hippocampal Neurogenesis

Exposure to heavy-ion radiation is considered a potential health risk in long-term space travel. It may result in the loss of critical cellular components in complex systems like the central nervous system (CNS), which could lead to performance decrements that ultimately could compromise mission goals and long-term quality of life. Specific hippocampal-dependent cognitive impairment occurs after whole-body 56Fe-particle irradiation, and while the pathogenesis of this effect is not yet clear, it may involve damage to neural precursor cells in the hippocampal dentate gyrus. We irradiated mice with 1-3 Gy of 12C or 56Fe ions and 9 months later quantified proliferating cells and immature neurons in the dentate subgranular zone (SGZ). Our results showed that reductions in these cells were dependent on the dose and LET. When compared with data for mice that were studied 3 months after 56Fe-particle irradiation, our current data suggest that these changes are not only persistent but may worsen with time. Loss of precursor cells was also associated with altered neurogenesis and a robust inflammatory response. These results indicate that high-LET radiation has a significant and long-lasting effect on the neurogenic population in the hippocampus that involves cell loss and changes in the microenvironment.

Negative Symptoms and Specific Cognitive Impairments as Combined Targets for Improved Functional Outcome Within Cognitive Remediation Therapy

Negative symptoms and poor cognition are both associated with poor functional outcome in schizophrenia. This poor functional outcome has been attributed to poor cognition rather than any independent contribution from symptoms. Identifying target cognitive processes and mechanisms that predict community function, and possible moderator effects of negative symptoms, will allow the development of cognitive remediation programs that are successful in improving functional outcome. A referred sample of 53 in- and outpatients with schizophrenia with general cognitive impairment (including 28 with severe negative symptoms) and 22 healthy controls, balanced for premorbid IQ, were compared cross sectionally on measures of community shopping skills, executive function, and working memory. Across the groups, there were direct relationships between community functioning and specific executive functions, and there were interactions between group membership and the types of associations found. Working memory was independently associated with accurate community functioning only in people with schizophrenia and negative symptoms. This association was not due to the sole presence of working memory impairment or just to negative symptoms. Poor community function is predicted both by specific cognitive impairments that are prominent in people with negative symptoms and through the moderating effect of negative symptoms on the working memory-community function relationship. This may reflect a synergistic association between symptoms and cognition: negative symptoms arise from cognitive impairment but also impact detrimentally on working memory functioning. Both cognitive processes and negative symptoms should be targeted in cognitive remediation to effect the greatest change in community functions.

Assessing Dysfunction Using Refined Cognitive Methods

Instruments currently being used to assess cognitive dysfunction do not grant us the granularity to pinpoint the specific cognitive impairments associated with various disorders. With the advent of sophisticated neuroimaging methods and lesion data, we are in a better position to understand the component processes of the various psychological functions. Here we describe 2 such functions and elucidate how the same refined cognitive methods that are being used to understand the processes underlying these functions can be applied to exploring dysfunctions associated with various psychological disorders.

Distinguishing Between Clinical and Minimal Hepatic Encephalopathy on the Basis of Specific Cognitive Impairment

It is well-known that liver cirrhosis is frequently accompanied by a wide range of neuropsychiatric abnormalities, including general and specific cognitive impairment. The aim of this study was to investigate which cognitive functions are selectively compromised in Hepatic Encephalopathy (HE) and to clarify the relationship between clinically overt or nonovert HE and the different forms and degrees of decay in cognitive deficits. Twenty-two patients without overt HE and 12 patients who showed overt HE at the first level of severity, along with matched control subjects, were compared in several cognitive domains. The results showed significant differences in some measures of attention between patients with minimal HE (mHE) and patients with overt HE. There were also notable differences in verbal short-term memory between patients with mHE and healthy subjects. Thus, we can hypothesize that there is a linear diminution in short-term memory and attentional performance starting from healthy patients, moving toward patients with mHE, and finally progressing toward patients with the first grade of overt HE. There are two types of diminution that we noted: between patients with mHE and the overt form, the decline in the attentional domain was more evident, while between healthy subjects and mHE patients, short-term memory showed a more evident decline.

Cognitive Dysfunction, Hippocampal Atrophy and Glucocorticoid Feedback in Alzheimer’s Disease

The hippocampal formation is damaged early in Alzheimer's disease (AD). An association between temporal lobe volume and cognitive function has been shown in several studies. Increased limbic-hypothalamic-pituitary-adrenal (LHPA) axis function has been suggested to be related to hippocampal atrophy and cognitive impairment. Our hypothesis was that there is a clear link between hippocampal volume -- notably of the CA1 region -- memory (episodic and visuospatial) and decreased feedback sensitivity in the LHPA axis in AD. Sixteen medication-free outpatients with mild to moderate AD were included. Hippocampal volume was measured with magnetic resonance imaging. Dexamethasone suppression tests were performed using .5 mg and .25 mg dexamethasone. Three different components in the neuropsychological battery -- Rey 15 item memory test, Alzheimer's Disease Assessment Scale (ADAS) word recall and spatial span from Wechsler Adult Intelligence Scale - Revised neuropsychological instrument (WAIS-R NI) -- were found to represent episodic and visuospatial memory. Low hippocampal CA1 volume and high post-dexamethasone cortisol levels in combination were significantly associated with Rey 15 item memory and spatial span test outcomes. No association was found between LHPA feedback and hippocampal volume. Low hippocampal volume and a disturbed negative feedback in the LHPA axis link to specific cognitive impairments in Alzheimer's disease.

Prefrontal cognitive functions in stabilized first-episode patients with schizophrenia spectrum disorders: A dissociation between dorsolateral and orbitofrontal functioning

Specific prefrontal cognitive impairments have been reported in first-episode and chronic schizophrenia. We sought to investigate potential impairments in specific prefrontal cortical cognitive functions among stabilized patients with a first-episode of schizophrenia. A sample of 80 individuals with a first-episode of schizophrenia spectrum disorders and 22 healthy volunteers underwent a neurocognitive battery assessing orbitofrontal (OFC) [The Iowa Gambling Task (GT)], and dorsolateral prefrontal (DLPFC) functions (WAIS III Backward digits, verbal fluency test (FAS), and Trail Making Test). Cognitive data were obtained following stabilization of acute psychotic symptoms. Clinical symptoms after six weeks of treatment were assessed by using the SAPS and SANS scales. While there were no significant group differences in overall scores and in the profile of progress of performance along periods on the GT, patient group showed a significant impairment when performing DLPFC tasks. Only FAS score was correlated to the severity of negative symptomatology. The OFC functions are unimpaired at the early phases of psychosis and in contrast there is a significant deficit in DLPFC functions in first-episode of schizophrenia.

Frontal-Striatal Dysfunction During Planning in Obsessive-Compulsive Disorder

Dysfunction of frontal-striatal, particularly orbitofrontal-striatal, circuitry has been implicated in the pathophysiology of obsessive-compulsive disorder (OCD), characterized by obsessions, ritualistic behavior, anxiety, and specific cognitive impairments. In addition, neuropsychological studies in OCD have reported impairments in visuospatial tasks and executive functions, such as planning. To determine whether dorsal prefrontal-striatal dysfunction mediates planning impairment in patients with OCD. A parametric self-paced pseudorandomized event-related functional magnetic resonance imaging version of the Tower of London task was used in 22 medication-free patients with OCD and 22 healthy control subjects. This paradigm, allowing flexible responding and post hoc classification of correct responses, was developed to compare groups likely to differ in performance. Behavioral results showed significant planning impairments in OCD patients compared with control subjects. During planning, decreased frontal-striatal responsiveness was found in OCD patients, mainly in dorsolateral prefrontal cortex and caudate nucleus. In addition, OCD patients showed increased, presumably compensatory, involvement of brain areas known to play a role in performance monitoring and short-term memory processing, such as anterior cingulate, ventrolateral prefrontal, and parahippocampal cortices. These findings support the hypothesis that decreased dorsal prefrontal-striatal responsiveness is associated with impaired planning capacity in OCD patients. Because the described frontal-striatal dysfunction in OCD is independent of state anxiety and disease symptom severity, we conclude that executive impairment is a core feature in OCD.