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PubMed2006

Nicotine and cognitive efficiency in alcoholics and illicit stimulant abusers: implications of smoking cessation for substance users in treatment.

Cigarette smoking is prevalent among alcoholics and illicit substance abusers. However, the potentially confounding effect of nicotine on studies of cognition in detoxified substance users has rarely been addressed. In the current study of 87 participants, behavioral and electrophysiological indices of cognitive efficiency were measured in tobacco smokers from four groups: alcoholics, illicit stimulant abusers, concurrent abusers, and control subjects. Data were collected from 2001 to 2003. We hypothesized that acute nicotine administration would modify cognitive deficits in alcoholics and illicit stimulant abusing groups. An adaptation of the Rapid Visual Information Processing task was administered after stabilization of nicotine levels via a high- or low-dose transdermal nicotine patch. Across groups, increased nicotine dose was associated with decreased reaction time (p = .03). A group x nicotine dose interaction trend was noted in which increased nicotine was associated with increased correct responding within the alcoholic group (p = .02). No significant differences in electrophysiology were observed. These results suggest that nicotine may modify cognitive efficiency in alcoholics and illicit stimulant abusers, a concept with relevance to both the design of experimental work and the treatment of alcohol and illicit stimulant dependence. Further work is needed to determine whether this effect predominantly reflects facilitation of cognition function or alleviation of nicotine withdrawal.

Administration, Cutaneous↗

PubMed1995

Maternal thyroid peroxidase antibodies during pregnancy: a marker of impaired child development?

Women with antibodies against the enzyme thyroid peroxidase [TPO-Ab; formerly microsomal antibodies (MsAb)] are at particular risk for developing postpartum thyroid dysfunction; the latter is significantly associated with postpartum depression. Although the negative effect of postpartum maternal depression on child development is well documented, the consequences of elevated titers of TPO-Ab during pregnancy and subsequent postpartum thyroid dysfunction on child development are not known. In a prospective study of a cohort of 293 pregnant women, the occurrence of TPO-Ab during gestation, thyroid dysfunction, and depression was investigated. Five years after delivery, child development was assessed in 230 children of the original cohort using the Dutch translation of the McCarthy Scales of Children's Abilities. Children of women with TPO-Ab during late gestation (n = 19, with normal thyroid function) had significantly lower scores (by t test) on the McCarthy Scales of Children's Abilities than antibody-negative women. The difference on the General Cognitive Scale, which reflects IQ scores, was substantial (10.5 points; t = 2.8; P = 0.005). After correction for possibly confounding variables, maternal TPO-Ab during gestation was found to be the most important factor related to the scores on the General Cognitive Scale (odds ratio = 10.5; 95% confidence interval = 3-34; P = 0.003). We conclude that children of pregnant women who had elevated titers of TPO-Ab but normal thyroid function are at risk for impaired development.

Adult↗

PubMed1987

[Physiology and physiopathology of somatic sensations studied in man by the method of evoked potentials].

The physiology of somatic sensation can be investigated noninvasively in man by recording the electric activity of peripheral nerves, spinal cord and brain. Since these responses have a small voltage, it is necessary to use electronic averaging methods for improving the signal-to-noise ratio. These methods are described and discussed, as well as principles of interpretation of somatosensory evoked potentials. It is agreed that the traces thus obtained involve a series of components (extracellular potentials) which reflect distinct neural generators. These generators have been identified and localized at different levels of the subcortical somatosensory pathway and in different cortical areas. Several components reflect generators located under the recording electrodes (nearfield potentials), while other reflect extracellular potentials diffusing at a distance in the volume conductor of the neck and head (farfield potentials). The analysis of these components provides a wealth of new data for the physiology and pathophysiology of the somatic sensory system in man. Besides so-called "obligatory" components that are present irrespective of the attention of the subject, the studies have uncovered "cognitive" components which reflect neural mechanisms involved in the intellectual processus of perception and decision.

Animals↗

PubMed2001

Dementia and neurodevelopmental predisposition: cognitive dysfunction in presymptomatic subjects precedes dementia by decades in frontotemporal dementia.

Dementia is typically thought of as a disease caused by the process of aging. Few studies have addressed the premorbid neuropsychological alterations in subjects at risk for the disease--an issue of great importance for the understanding and treatment of degenerative dementias. We used knowledge of the mutation carrier status in a family with inherited dementia to address this issue more efficiently than is possible in the general population, or in cases of inherited dementia where the mutational basis is unknown. Standard neuropsychological tests were used to detect evidence of dysfunction in frontal executive systems in 10 presymptomatic subjects with known mutation carrier status in the highly penetrant condition, frontotemporal dementia and parkinsonism linked to chromosome 17. Presymptomatic carriers demonstrated cognitive dysfunction that was not present in 6 nonmutation-carrying relatives. Strikingly, frontal-executive dysfunction was apparent in some of the youngest mutation carriers many decades prior to the predicted onset of dementia. Thus, this dysfunction may reflect the native cognitive capacities of affected subjects. These results suggest a potentially important neurodevelopmental component to a dementing condition that has been predominantly considered to be a disease of aging; accordingly, this issue warrants study in other families to assess the applicability of these findings.

Adolescent↗

PubMed1996

Continuing the search for cholinergic factors in cognitive dysfunction.

The objective of the experiments reported here was to explore three hypotheses regarding cholinergic processes underlying the development of progressive degenerative dementia (PDD). One possibility involved the downregulation of muscarinic receptors (mAChR) with aging, thus reducing the capability of the cholinergic system to support normal memory and other cognitive functions. The results of downregulation to 10% of normal produced only a temporary effect, the system having the capability to repair the damage. A second hypothesis predicted that a chronic hypocholinergic state can produce structural changes that are reflected in persisting cognitive dysfunctions. Chronic administration of a false cholinergic transmitter in the diets of weanling rats mimicked such a state which, if maintained for a protracted period, produced many of the features of PDD in humans. When the diet was returned to normal, biochemical and physiological processes recovered fully. However, memory impairment continued. This suggested the possibility that the behavioral losses were mediated by persisting morphological changes in the CNS. The third hypothesis proposes that these changes may be due to cell loss resulting from impaired phospholipid metabolism. Changes in sphingomyelin, one of the two major Ch-containing lipids in cell membranes, could increase amounts of ceramide, an inducer of programmed cell death (apoptosis). Tests of this hypothesis are nearing completion.

Animals↗

PubMed1978

Cognitive mode and asymmetry in cerebral functioning.

Male graduate students from the fields of sculpture, psychology, and law were used to test the assumption that an individual's cognitive mode (verbal-analytic vs. spatial-holistic) is related to actual laterality in cerebral functioning. A measure of asymmetry of cognitive mode for each student, based on relative performance on three verbal-analytic tests compared to three spatial-holistic tests, successfully discriminated occupational groups. Laterality in cerebral functioning was indexed by relative reaction times to discriminate visual stimuli presented unilaterally to the left or right hemisphere. Reaction times to discriminate faces were less for the right hemisphere, while letters were discriminated faster by the left hemisphere. However, measures of cerebral laterality were not related to occupational group membership nor to asymmetry of cognitive mode. Asymmetry in performance on tests of cognitive mode may reflect an individual's general approach to problem solving, but is not closely related to laterality in cerebral functioning.

Adult↗

PubMed1999

P300 event-related potentials in probable dissociative generalized amnesia.

1. To investigate whether abnormalities in objective neurophysiologic measures are observable in patients with probable dissociative generalized amnesia, the P300 and N100 event-related potentials were evaluated in six such patients in both acute stage and after recovery from amnesia. Findings were compared with those in 12 age- and gender-matched healthy subjects. 2. While latencies did not differ from those of control subjects, P300 amplitudes in acute-stage recordings were lower than those in controls. Repeated recordings in the patients showed a significant increase in P300 amplitude after recovery from amnesia. 3. Amplitude and latency of N100 did not differ between the patient and control groups, nor changed significantly after retrieval of memory. 4. These findings suggest that some unknown biological and/or psychologic mechanisms that cause retrograde autobiographic amnesia may impair cognitive function as reflected in an objective neurophysiologic measure such as the P300.

Adolescent↗

PubMed1998

Autism and autistic epileptiform regression with occipital spikes.

The electroencephalographic abnormalities seen in Landau-Kleffner syndrome (LKS) (language deterioration) are non-specific, and consist of a variety of epileptiform discharge patterns including continuous slow spike-wave discharges during sleep, focal sharp waves with spikes, and centrotemporal (rolandic) spikes. Similarly, the EEG abnormalities seen in autistic epileptiform regression (language and social/behavioral deterioration) are non-specific and overlap with those seen in LKS. By contrast, distinct epilepsy syndromes in otherwise normal children occur in the EEG-defined benign focal epilepsies of childhood. Occipital spikes or spike-wave present either in the older child with visual symptoms and headache or in the younger child with autonomic symptoms followed by brief or prolonged partial motor seizures. Seven young children (five from a consecutive series of 42) presenting clinically with autism or autistic regression and possible or definite seizures, whose EEGs revealed occipital spikes or spike-wave characteristic of the benign epilepsies, are reported. Although occipital spikes are commonly seen in young children as an age-dependent EEG-defined benign focal epilepsy, their high frequency in this population with cognitive difficulties suggests a possible causal relation. The effects of the epileptiform discharge on cognitive functioning presumably reflect extension into temporal and parietal lobes, rather than occipital disturbances per se.

Autistic Disorder↗

PubMed2006

Reflections of other minds: how primate social cognition can inform the function of mirror neurons.

Mirror neurons, located in the premotor cortex of macaque monkeys, are activated both by the performance and the passive observation of particular goal-directed actions. Although this property would seem to make them the ideal neural substrate for imitation, the puzzling fact is that monkeys simply do not imitate. Indeed, imitation appears to be a uniquely human ability. We are thus left with a fascinating question: if not imitation, what are mirror neurons for? Recent advances in the study of non-human primate social cognition suggest a surprising potential answer.

Animals↗

PubMed1999

Cognitive reserve and mortality in dementia: the role of cognition, functional ability and depression.

OBJECTIVE: This study examined whether dementia patients with greater cognitive reserve had increased mortality rates, and whether this association was different across strata of cognition, functional ability and depression. METHODS: In the community-based Amsterdam Study of the Elderly, 261 non-institutionalized dementia patients, identified using the Geriatric Mental State Schedule (GMS), were followed for an average of 55.5 months after which mortality data were obtained. Cognitive reserve was indicated by years of education and pre-morbid intelligence (measured using the Dutch Adult Reading Test). Cognition, functional ability and depression were indicated by Mini-Mental State scores, ADL and IADL measurements and GMS depressive syndrome, respectively. RESULTS: During the follow-up 146 persons (55.9%) died. Cox regression analyses showed that more highly educated dementia patients had higher mortality rates, only if they had low MMSE scores or if they had a concurrent depression. Pre-morbid intelligence was associated with a higher mortality rate, independent of cognition, but this association was much stronger among patients with depression. The positive association between education or intelligence and mortality was not modified by functional disabilities. CONCLUSIONS: The results suggest that dementia patients with greater cognitive reserve have increased mortality rates, only if the disease has progressed to such an extent that clinical symptoms are more severe. In this respect, the reserve hypothesis needs a modification. Depression in dementia patients with greater cognitive reserve may reflect a subgroup of patients with poor prognosis.

Aged↗

PubMed1986

Structural brain correlates of emotional disorder in multiple sclerosis.

Eighty-seven patients with definite multiple sclerosis (MS) were examined neurologically and administered the Mini-mental State examination (MMS) to assess cognitive disability at the beginning and end of a one-year study. A CT scan was performed in 37. A group of 16 patients with stable spinal cord injuries (SCI) were studied in a similar manner. Of the MS patients, 47% had a mean General Health Questionnaire (GHQ) score in the abnormal range. This was a higher rate than in SCI patients (P = 0.004). Mean depression scores were similar in MS and SCI patients, but MS patients with brain involvement were more depressed than those with cord lesions only (P = 0.05). Depression score was unrelated to functional disability but was correlated with the degree of neurological impairment (P = 0.03). Euphoric patients were more likely to have brain involvement (P = 0.006), to have progressive MS (P less than 0.0001), and to have enlarged ventricles (P = 0.04) and were more impaired cognitively (P = 0.04) than noneuphoric patients. These results suggest that depression in MS patients is partly determined by the presence of brain involvement, but that it is also an emotional reaction to the disorder. Euphoria and cognitive disorder are reflections of brain involvement.

Adult↗

PubMed2006

Cognitive neuroimaging: cognitive science out of the armchair.

Cognitive scientists were not quick to embrace the functional neuroimaging technologies that emerged during the late 20th century. In this new century, cognitive scientists continue to question, not unreasonably, the relevance of functional neuroimaging investigations that fail to address questions of interest to cognitive science. However, some ultra-cognitive scientists assert that these experiments can never be of relevance to the study of cognition. Their reasoning reflects an adherence to a functionalist philosophy that arbitrarily and purposefully distinguishes mental information-processing systems from brain or brain-like operations. This article addresses whether data from properly conducted functional neuroimaging studies can inform and subsequently constrain the assumptions of theoretical cognitive models. The article commences with a focus upon the functionalist philosophy espoused by the ultra-cognitive scientists, contrasting it with the materialist philosophy that motivates both cognitive neuroimaging investigations and connectionist modelling of cognitive systems. Connectionism and cognitive neuroimaging share many features, including an emphasis on unified cognitive and neural models of systems that combine localist and distributed representations. The utility of designing cognitive neuroimaging studies to test (primarily) connectionist models of cognitive phenomena is illustrated using data from functional magnetic resonance imaging (fMRI) investigations of language production and episodic memory.

Brain Mapping↗

PubMed1998

Lateralized frontal blood flow increases during fluency tasks: influence of cognitive strategy.

Difficulties with verbal fluency tasks (VFIT) have been shown mainly to be associated with left frontal lobe pathology in lesion studies. The design fluency test (DFT) is a non-verbal analogue of word fluency tasks and has, in patients with right frontal lobe pathology, been coupled to an inability to perform well. Regional cerebral blood flow measurements (rCBF) were made in normals to elucidate the involvement of frontal and frontotemporal brain regions during the performance of VFT and DFT. In addition, the subjects' reports were used for obtaining information about the cognitive strategy used when solving the tasks. The results confirm previous CBF findings showing a mainly left-sided frontal activation during the VFT. During the DFT significant flow augmentations were seen in both frontal lobes compared to baseline. Furthermore, the use of different strategies was reflected in different patterns of brain activation. Our results support the proposal that the left frontal cortical area is engaged in the generation of internally driven responses. Furthermore, we argue that the cortical areas engaged during the execution of these tasks may reflect differences in cognitive strategy.

Adult↗

PubMed2001

Performance on the Mattis Dementia Rating Scale in patients with vascular dementia: relationships to neuroimaging findings.

Impairment on screening measures such as the Mattis Dementia Rating Scale (MDRS) provides evidence of dementia in patients with cerebrovascular disease. However, the relationships between neuroimaging findings and performance on the MDRS in vascular dementia (VD) have not been determined. In the present study, we examined the relationships between subcortical hyperintensity (SH) volume and whole brain volume (WBV) on the subscales and total score of the MDRS. Results revealed that SH accounted for a significant amount of variance on the Initiation/Perseveration and Construction subscales, whereas WBV accounted for a significant amount of variance on the Memory subscale. The total score on the MDRS was found to be significantly related to WBV but not SH. These results suggest that subcortical damage and brain volume account for different aspects of cognitive decline in VD and that overall cognitive impairment may reflect cortical and subcortical involvement.

Aged↗

PubMed2003

Spatial disorientation in Alzheimer's disease: the remembrance of things passed.

BACKGROUND: Patients with Alzheimer's disease (AD) and many older adults become lost even in familiar surroundings. This is commonly attributed to memory impairment, but it may reflect impaired spatial cognition. METHODS: The authors examined the role of memory, perceptual, and cognitive mechanisms in spatial disorientation by comparing the performance of normal young (YN), middle-aged (MA), older adult (OA), and AD subjects on neuropsychological and spatial orientation tests. RESULTS: The tendency to become lost is shared by almost all patients with AD (93%) and some OA subjects (38%). This impairment is not related to memory impairment. Instead, it reflects an inability to link recognized scenes with locations in the environment. CONCLUSIONS: Spatial disorientation reflects the impaired linking of landmarks and routes that should be assessed in conjunction with routine memory testing in elderly patients.

Adult↗

PubMed2005

Genetic covariation between event-related potential (ERP) and behavioral non-ERP measures of working-memory, processing speed, and IQ.

The aim of this study was to identify genetic covariants for fundamental measures of brain function (event-related potentials (ERPs): P300 latency and slow wave amplitude recorded in a working-memory task) and more complex cognitive measures (behavioral non-ERP measures: working-memory performance, information processing speed, IQ). Data were collected from 252 monozygotic and 297 dizygotic twin pairs aged 16. Multivariate modeling identified two independent genetic factors associated with processing speed that also influenced working-memory performance (one reflected the duration of neural activity required to evaluate target information, the other reflected more general cognitive and speed-related abilities). However, the allocation of neural resources, as assessed by ERP slow wave amplitude measures, was not associated with the other cognitive measures investigated. Thus, of the ERP measures examined, P300 latency, but not slow wave amplitude, may be an informative measure to include (i.e., with working-memory performance) in future multivariate linkage and association analyses of cognitive function.

Cognition↗

PubMed1996

Quality of life in brain tumor patients.

With the aim of evaluating the quality of life (QL) of 101 brain tumor patients, a multidimensional approach was adopted, using the Functional Living Index-Cancer (FLIC) as a global measure of well-being, the Karnofsky Performance Scale (KPS) and the Index of Independence in Activity of Daily Living (ADL) as indices of physical and functional dimensions, the State-Trait Anxiety Inventory (STAI) and the Self-Rating Depression Scale (SRDS) for psychological assessment, and neuropsychological tests for abstract reasoning, attention, memory and frontal lobe functions. The patients were grouped on the grounds of disease stage and treatment. The FLIC and KPS ratings increased from the patients who had just undergone surgery to patients who were disease-free after completing chemotherapy and radiotherapy, thus showing that the QL may improve during the disease despite aggressive treatments, providing there is no tumor recurrence. However, only the FLIC consistently discriminated the patients' stratification. The ADL revealed no between-group differences, whereas the STAI and SRDS revealed the presence of emotional troubles at the beginning and at the end of treatment. Cognitive impairment was more serious after radiotherapy and chemotherapy, as well as in patients with tumor recurrence. The FLIC significantly correlated with all of the other scales used, showing that it is useful in summarizing both the physical and psychosocial impairment of brain tumor patients. Of the pathological variables, a tumor location in the anterior right hemisphere or diencephalon was associated with high FLIC ratings, may be due to the minor cognitive impairment observed in patients with these tumor sites. Of the demographic variables, the level of education was associated with high FLIC ratings, thus highlighting the role of psychosocial environment in improving the QL. The use of a multidimensional approach or a global index of well-being that also reflects psychosocial and cognitive aspects proved to be more appropriate than traditional functional instruments (such as the KPS) in assessing the QL of brain tumor patients and in detecting the extent of the disease.

Adult↗

PubMed1983

Enhanced visual memory during hypnosis as mediated by hypnotic responsiveness and cognitive strategies.

To investigate the hypothesis that hypnosis has an enhancing effect on imagery processing, as mediated by hypnotic responsiveness and cognitive strategies, four experiments compared performance of low and high, or low, medium, and high, hypnotically responsive subjects in waking and hypnosis conditions on a successive visual memory discrimination task that required detecting differences between successively presented picture pairs in which one member of the pair was slightly altered. Consistently, hypnotically responsive individuals showed enhanced performance during hypnosis, whereas nonresponsive ones did not. Hypnotic responsiveness correlated .52 (p less than .001) with enhanced performance during hypnosis, but it was uncorrelated with waking performance (Experiment 3). Reaction time was not affected by hypnosis, although high hypnotizables were faster than lows in their responses (Experiments 1 and 2). Subjects reported enhanced imagery vividness on the self-report Vividness of Visual Imagery Questionnaire during hypnosis. The differential effect between lows and highs was in the anticipated direction but not significant (Experiments 1 and 2). As anticipated, hypnosis had no significant effect on a discrimination task that required determining whether there were differences between pairs of simultaneously presented pictures. Two cognitive strategies that appeared to mediate visual memory performance were reported: (a) detail strategy, which involved the memorization and rehearsal of individual details for memory, and (b) holistic strategy, which involved looking at and remembering the whole picture with accompanying imagery. Both lows and highs reported similar predominantly detail-oriented strategies during waking; only highs shifted to a significantly more holistic strategy during hypnosis. These findings suggest that high hypnotizables have a greater capacity for cognitive flexibility (Batting, 1979) than do lows. Results are discussed in terms of several theoretical approaches: Paivio's (1971) dual-coding theory and Craik and Tulving's (1975) depth of processing theory. Additional discussion is given to the question of whether hypnosis involves a shift in cerebral dominance, as reflected by the cognitive strategy changes and enhanced imagery processing.

Adult↗