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PubMed1999

Understanding the neuropsychiatric symptoms of Huntington's disease.

Huntington's disease (HD) is a neurodegenerative process that is manifest as deterioration in a person's motor control, cognition and emotional stability. Emotional instability is reflected through a variety of symptoms such as personality change, anxiety and irritability. These symptoms are complex and often poorly understood. Changes in the caudate are thought to contribute to psychiatric alterations seen in HD patients. An understanding of common psychiatric disorders seen in HD allows nurses to develop appropriate interventions.

Cognition Disorders↗

PubMed2005

Resting SPECT-neuropsychology correlation in very mild Alzheimer's disease.

OBJECTIVE: To investigate the relationships between brain function and some of the most frequently impaired cognitive domains in the first stages of Alzheimer's disease (AD), we searched for correlation between the scores on 3 neuropsychological tests and brain perfusion, assessed by single photon emission computed tomography (SPECT) in patients with very mild AD. METHODS: Twenty-nine consecutive outpatients (mean age 78.2+/-5.5) affected by probable AD in the very mild phase (i.e. with a score > or =20 on the mini-mental state examination, MMSE) underwent brain SPECT with (99m)Tc-ethylcisteinate dimer. For correlative purposes, word list learning (by the selective reminding test, SRT), constructional praxis test (CPT) and visual search test (VST) were chosen a priori out of an extended battery employed to diagnose AD at first patient evaluation. Voxel-based correlation analysis was achieved by statistical parametric mapping (SPM99) with a height threshold of P=0.005. Age, years of education and the MMSE score were inserted in the correlative analysis as confounding variables. RESULTS: The SRT score showed correlation with brain perfusion in 3 clusters of the left hemisphere, including the post-central gyrus, the parietal precuneus, the inferior parietal lobule and the middle temporal gyrus, and in one cluster in the right hemisphere including the middle temporal gyrus and the middle occipital gyrus. The CPT score was significantly correlated with brain perfusion in the parietal precuneus and the posterior cingulate gyrus in the left hemisphere, whereas the VST score gave a significant correlation with brain perfusion in a left cluster including the parietal precuneus and the superior temporal gyrus. CONCLUSIONS: Cognitive impairment in very mild AD is reflected by brain dysfunction in posterior associative areas, with peculiar topographical differences proper of each domain. The parietal precuneus was a common site of correlation of all 3 neuropsychological tests. This region, together with the posterior cingulate and the superficial posterior temporal-parietal cortex, is thought to be affected by disconnection from the mesial temporal lobe, besides being directly affected by increased oxidative stress and by atrophy as well. The impairment of these areas is thought to contribute to cognitive decline in verbal memory, constructional praxis and visual sustained attention which are indeed among the earliest signs of cognitive impairment in AD. SIGNIFICANCE: Assessing the relationships between neuropsychology and brain functional imaging is a key approach to clarify the pathophysiology of cognitive failure in AD; the specificity of these findings in AD remains to be proven through comparison with correlation achieved in matched controls.

Aged↗

PubMed2005

Diabetes and brain aging: epidemiologic evidence.

Increasingly, data from epidemiologic studies suggest diabetes is a risk factor in old age for brain aging, including cognitive impairment and dementia. These associations may reflect a direct effect on the brain of hyperglycemia, or the effects of the diabetes-associated comorbidities of hypertension, dyslipidemia, or hyperinsulinemia. Epidemiologic data on diabetes and brain aging are reviewed. A brief overview is also given of the physiologic mechanisms supporting the epidemiologic data.

Aged↗

PubMed1999

Effectiveness of sensory stimulation on tactile extinction.

Eleven brain-damaged patients with extinction were asked to report double tactile stimuli before, during, and after optokinetic stimulation and transcutaneous electrical stimulation of the posterior neck region. The goal of the study was to test whether tactile extinction is sensitive to these experimental manipulations in order to better understand the nature of the disorder. Both of these sensory stimulations are known to be effective in modulating only higher-order (cognitive) disorders of spatial coding, such as visual hemineglect, deficit of position sense, hemianesthesia, etc. When applied to the side contralateral to the cerebral lesion, both optokinetic and transcutaneous electrical stimulation significantly affected patients' performances, increasing the amount of detections of contralesional double stimuli. A tendency towards worse performance was observed when sensory stimulation was applied to the ipsilesional side. The reported effectiveness in reducing tactile extinction suggests that the deficit can not be fully ascribed to a peripheral sensory disorder and that it reflects damage to a higher-order cognitive function involved in contralesional space representation or in the deployment of attention to that side of space. The nature of the close relationship between extinction and hemineglect is also discussed from the point of view of extinction as a deficit of space coding.

Aged↗

PubMed2006

EEG and MRI correlates of mild cognitive impairment and Alzheimer's disease.

OBJECTIVE: To investigate whether cognitive function in the spectrum of normal aging to Alzheimer's disease is better reflected in MRI or EEG measures, or a combination of both. METHODS: Cognitive functions were tested in 33 elderly subjects: 10 with probable Alzheimer's disease, 11 with mild cognitive impairment and 12 controls. Structural brain parameters were derived from conventional MRI and a quantitative MR technique called magnetization transfer imaging. The EEG provided measures of brain function. We performed multiple linear regression analyses to relate EEG and MRI parameters to global cognition, memory, language and psychomotor speed. RESULTS: The model showed EEG alpha reactivity during eyes open to be the primary factor associated with global cognition, memory and language skills. Brain atrophy was the primary factor associated with psychomotor speed. Furthermore, EEG alpha reactivity during eyes open explained significant additional variability in psychomotor speed. CONCLUSION: EEG and MRI are each associated with different aspects of cognitive function and complement each other in their relations to psychomotor speed.

Aged↗

PubMed1996

Cognitive and neurobiologic markers of early Alzheimer disease.

Recent studies indicate that impairments in two cognitive domains characterize the cognitive abnormalities that appear earliest in the course of Alzheimer disease (AD). These cognitive domains pertain to memory and executive function ability; in particular, memory test scores reflecting the difference between immediate and delayed recall and tasks that assess cognitive flexibility (e.g., set-shifting). Preliminary data indicate that tasks of this nature, along with specific genetic information (i.e., APOE-4 status), are important in identifying which individuals with recent cognitive changes (considered to have "questionable" disease) will progress to the point where they meet criteria for AD over time. When this cognitive and genetic information is combined with neuroimaging measures targeted at the brain regions demonstrating pathology early in AD, it may serve as specific and accurate prognostic markers of AD.

Alcohol Amnestic Disorder↗

PubMed2002

Stimulus- and event-related evoked potentials: from neuroscience to clinical neuropharmacology.

Synaptic neural (and neural system) functions are peculiarly sensitive to neuroactive compounds. Pharmacological interference/modulation is readily reflected by modifications in the organization of central nervous system (CNS), electrophysiologic signals occurring spontaneously in response to sensory stimulation (stimulus-related or evoked responses) or elicited in conjunction with sensory, motor or cognitive events (event-related potentials). Evoked responses reflect the basic physiology of sensory processes, while event-related potentials combine the time/space resolution of electrophysiologic signals with the specificity of eliciting neuropsychological conditions. The rationale for investigating drug effects on evoked and event-related potentials is manifold. Both are related to sensory and operant behavior and under suitable experimental conditions allow interpretation of drug-related changes in terms of CNS excitability. Some continuity between observations in man and in vivo or in vitro animal data is often possible. Proper handling of the stimulus physical properties or experimental/situational links may allow the responses to be related to sensory input or to neuropsychological manipulation of selectively activated CNS functions or functional subsystems and therefore to control spontaneous variability. This review summarizes today's knowledge of the application of electrophysiology to human neuropharmacology, with due reference to basic pharmacology and experimental evidence.

Evoked Potentials↗

PubMed2004

Prognostic value of evoked responses and event-related brain potentials in coma.

The behaviourally unresponsive patient, unable to exhibit the presence of cognition, constitutes a conundrum for health care specialists. Prognostic uncertainty impedes accurate management decisions and the application of ethical principles. An early, reliable prognosis is highly desirable. In this review investigations studying comatose patients with coma of different etiologies were selected. It is concluded that objective prognostication is enhanced by the use of electrophysiological tests. Persistent abnormalities of brainstem auditory evoked potentials and short-latency somatosensory evoked potentials reliably indicate the likelihood of irreversible neurological deficit or death. Meanwhile, the presence of "cognitive" event-related brain potentials (e.g., P300 and mismatch negativity) reflects the functional integrity of higher level information processing and, therefore, the likelihood of capacity for cognition. An approach that combines clinical and electrophysiological values provides optimal prediction of outcome and level of disability.

Acoustic Stimulation↗

PubMed2004

Neural synchronization deficits to auditory stimulation in bipolar disorder.

Patients with bipolar disorder show cognitive deficits and disorganized behavior, which may reflect a disturbance in neural synchronization. We tested whether EEG measures of auditory neural synchronization were abnormal in bipolar disorder. Nineteen symptomatic patients with bipolar disorder and 32 non-psychiatric control subjects were evaluated. Click trains (500 ms duration) presented at 20, 30, 40 and 50 Hz were used to evoke EEG synchronization. Patients with bipolar disorder showed reduced power across the frequencies of stimulation. Phase-locking across trials was also disturbed in bipolar disorder, consistent with poor phase synchronization between the stimulus and EEG. Abnormal high frequency neural synchronization may contribute to cognitive deficits in bipolar disorder.

Acoustic Stimulation↗

PubMed1994

Athletes and pain tolerance.

Athletes' attitudes towards pain, and the cognitive strategies they use while experiencing pain, may be reflected in their pain tolerance levels and their performance and adherence to sport injury rehabilitation. Association and dissociation are 2 of the more popular cognitive strategies, and most research has found that these strategies increase pain tolerance and performance. It has not clearly been established how these results are transferred to athletes overcoming the pain associated with injury rehabilitation. The major limitation of most of these pain induction techniques is that they are inherently safe, and individuals know that the induced pain can be terminated at any time. Not only will the stressor be terminated, but the pain experienced will also decline because the pain is due to the stimulation. Thus, it is possible that pain tolerance and performance levels are higher in experimental settings than would normally be in real-life situations. However, exercise-induced muscle soreness is one pain induction technique which attempts to alleviate this limitation and therefore provide more realistic levels of pain to tolerate. The pain, stiffness, prolonged reduction in muscle strength, and decreased range-of-motion that appear 24 to 48 hours after strenuous eccentric exercise does not fully subside until 8 to 10 days after the initial bout of exercise. Study participants experience long-lasting, real-life pain. Thus, it is worthwhile for those involved in sport injury rehabilitation to be aware of the effectiveness of these cognitive strategies that may assist athletes to overcome the pain associated with exercise-induced muscle soreness, and how this relates to rehabilitation.

Athletic Injuries↗

PubMed2005

What does an intermediate success rate mean? An analysis of a Piagetian liquid conservation task in the great apes.

The study investigates what an intermediate success rate means in bonobos, chimpanzees, and orangutans. Apes participated in liquid conservation experiments where they had to track the larger of two different quantities of juice after various kinds of transformations [Suda, C., & Call, J. (2004). Piagetian liquid conservation in the great apes (Pan paniscus, Pan troglodytes, and Pongo pygmaeus). Journal of Comparative Psychology, 118, 265-279). When making a decision, apes sometimes demonstrated hesitant behavior, concurrently pointing to both alternatives or successively changing their choice. Moderately successful apes showed more hesitation than highly successful or unsuccessful apes. The results are consistent with the cognitive conflict model: The experiments created a higher degree of cognitive conflict on moderately successful apes than on very successful or unsuccessful apes. This indicates that an intermediate performance reflects the joint operation and potential conflict between two different cognitive strategies (identity and appearance) inherent to the Piagetian conservation task.

Analysis of Variance↗

PubMed1977

Effect of perceptual processing strategies on problem solving of reflective and impulsive children.

Several studies employing the "20 questions" test reported that reflective children asked proportionally more constraint-seeking (CS) questions than did impulsive children. The finding was interpreted as supporting the generally accepted view that reflective children are more mature and more efficient problem solvers than impulsive children. Inexplicably, the reflectives' higher proportion of CS questions was not associated with fewer questions to solution, that is, with greater efficiency. The present study examined an alternative hypothesis that differences in performance of impulsive and reflective children on the "20 questions" test are due to individual differences in preferred perceptual processing strategy rather than in cognitive maturity of problem-solving strategy. Efficiency of performance of reflective and impulsive children was shown to be related to type of stimuli and experimental conditions employed, supporting a perceptual rather than cognitive-maturational interpretation.

Child↗

PubMed2005

The neural correlates of direct and reflected self-knowledge.

Socrates said that in order to lead a balanced life one must, "know thyself." In two fMRI experiments, the present study examined the mechanisms mediating two ways in which the self can be known: through direct appraisals (i.e., an individual's own self-beliefs) and reflected appraisals (i.e., an individual's perception of how others view him or her). Experiment 1 examined the common and distinct neural bases of direct appraisals of the self, close others, and normative judgments of trait desirability. All three judgment types activated medial prefrontal cortex (MPFC) to a similar degree. Experiment 2 examined the common and distinct neural bases of (1) direct appraisals of self, a close other or a non-close other, and (2) reflected appraisals made from the perspective of a close or a non-close other. Consistent with Experiment 1, all judgment types activated MPFC. Direct appraisals of the self as compared to others more strongly recruited MPFC and right rostrolateral PFC. Direct appraisals as compared to reflected appraisals recruited regions associated with a first-person perspective (posterior cingulate), whereas reflected as compared to direct appraisals recruited regions associated with emotion and memory (insula, orbitofrontal, and temporal cortex). These results support models suggesting that MPFC mediates meta-cognitive processes that may be recruited for direct and reflected self appraisals depending upon the demands of a specific task.

Adult↗

PubMed2004

Parametric study of accuracy and response time in schizophrenic persons making visual or auditory discriminations.

The inability to modulate processing time in conjunction with varying difficulty levels may be a core component of schizophrenia's cognitive deficit. In this study we used a parametric design to demonstrate this group's inability to increase and decrease response times in association with varying levels of task demand during auditory and visual recognition tasks. Unlike participants with schizophrenia, healthy volunteers responded to increasing levels of difficulty and high error by robustly increasing their average response times. In the group with schizophrenia, the greater the correlation between a subject's Response-Time and error rate the better was the subject in his/her overall discrimination accuracy. The higher their correlations the better they performed across all levels of difficulty in both modalities. The schizophrenia group's tendency to process high and low error conditions with similar behavioral resources may reflect a relatively static, non-dynamic cognitive repertoire.

Adult↗

PubMedDate not supplied

Health outcomes and cognitive aspects of recalled negative life events.

OBJECTIVE: Integrative complexity reflects the level of intellectual resources allocated to coping with a particular situation or problem. This study explored whether the recall of very unpleasant memories would occur at a different level of complexity from that of neutral memories, and whether differences in complexity would be related to health outcomes. METHODS: A series of essays, some dealing with negative life experiences and others with trivial events, had been written by undergraduates for a previous study. Complexity scores of these two types of essays were compared, and were correlated with a composite measure of well-being (immunological assays, visits to the Student Health Center, and self-reported distress and substance abuse). RESULTS: Essays about negative experiences were significantly higher in complexity, implying the allocation of more cognitive effort to the narrative. Subjects who wrote about negative events showed a significant relationship between complexity and improvement in wellness: Complexity scores closer to the median were associated with the most improvement (p < 0.05). CONCLUSIONS: Recalling negative life experiences engages increased cognitive effort, just as coping with negative experiences does. However, both low and high cognitive involvement are associated with lower levels of well-being than is a moderate level. The findings have implications for the relation between cognitive and emotional processes and between cognitive processes and health, as well as for the specific issue of how emotionally negative events are reconstructed in memory.

Adaptation, Psychological↗

PubMed2006

Decreased theta event-related synchronization during working memory activation is associated with progressive mild cognitive impairment.

BACKGROUND: Among the different quantitative electroencephalographic markers, theta activity is known to reflect neural resources involved in memory processes and directed attention. Previous studies suggested that synchronization likelihood analysis in theta-band frequency might be a sensitive method to identify early alterations of neuronal networks in mild cognitive impairment (MCI). METHODS: We report here a longitudinal study of 24 MCI patients with theta event-related synchronization (ERS) analysis during the n-back working memory task and neuropsychological follow-up after 1 year. Statistical analysis included analysis of variance and logistic regression to assess the relationship between cognitive decline and theta ERS. RESULTS: Upon follow-up, 13 MCI patients showed progressive MCI and 11 remained stable. In both groups, the phasic increase in theta amplitude after stimulus presentation did not depend on working memory load and electrode sites. Progressive MCI cases displayed significantly lower theta ERS power over all electrode sites compared to stable MCI cases. Theta ERS was significantly related to the cognitive outcome explaining 15.5% of its variability. In terms of MCI classification, the best combination of sensitivity and specificity was 0.87 and 0.60, respectively, with an area under the corresponding receiver operating characteristic curve reaching 76%. CONCLUSIONS: The present data indicate that a decrease in the early phasic theta ERS power during working memory activation may predict cognitive decline in MCI. This phenomenon is not related to working memory load but may reflect the presence of early deficits in directed attention-related neural circuits in MCI.

Aged↗

PubMed1999

Fear of cognitive dyscontrol in relation to depression symptoms: comparisons between original and alternative measures of anxiety sensitivity.

Previous research has found that a facet of anxiety sensitivity (AS), referred to as fear of cognitive dyscontrol or fear of mental incapacitation, is associated with severity of depressed mood. Other research has extended the "fear of fear" concept to include fear of losing control over emotion in general (including depression). Because anxiety and depression share the common feature of general distress (Clark & Watson, 1991. Journal of Abnormal Psychology, 93, 19-30), the present study took a conservative approach and statistically controlled for the effect of trait anxiety and negative affectivity before contributions of AS to depression were examined. In a large college student sample (N = 348), facets of the original and alternative measures of AS were evaluated in attempts to predict severity of depression symptoms. Fear of cognitive dyscontrol facets from both measures of AS were significant predictors in the regression analyses. A new set of items reflective of control over emotions was also significant and both cognitive and emotional control added to the prediction of depression symptoms in a complementary fashion. Implications of these findings for identifying a proposed "depression sensitivity" are discussed.

Adolescent↗

PubMed2004

Personality predicts brain responses to cognitive demands.

Eysenck (1981) proposed that the personality dimension of introversion- extraversion (E) reflects individual differences in a cortical arousal system modulated by reticulothalamic- cortical pathways: it is chronically more active in introverts relative to extraverts and influences cognitive performance in interaction with task parameters. A circuit with connections to this system, including the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate (AC) cortex, has been identified in studies applying functional magnetic resonance imaging (fMRI) to a broad range of cognitive tasks. We examined the influence of E, assessed with the Eysenck Personality Questionnaire-Revised (Eysenck and Eysenck, 1991), in fMRI activity during an "n-back" task involving four memory loads (0-, 1-, 2-, and 3-back) and a rest condition in healthy men. To confirm the specificity of E effects, we also examined the effects of neuroticism and psychoticism (P) scores. We observed that, as predicted by Eysenck's model, the higher the E score, the greater the change in fMRI signal from rest to the 3-back condition in the DLPFC and AC. In addition, E scores were negatively associated with resting fMRI signals in the thalamus and Broca's area extending to Wernicke's area, supporting the hypothesized (negative) relationship between E and resting arousal. P scores negatively correlated with resting fMRI signal in the globus pallidus-putamen, extending previous findings of a negative relationship of schizotypy to striatal activity seen with older neuroimaging modalities to fMRI. These observations suggest that individual differences affect brain responses during cognitive activity and at rest and provide evidence for the hypothesized neurobiological basis of personality.

Adult↗