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PubMed2005

Differences in diabetes management of nursing home patients based on functional and cognitive status.

OBJECTIVES: To describe practice patterns regarding diabetes management among nursing home (NH) physicians and to identify variation in this practice based on patient characteristics. DESIGN: Mailed survey. PARTICIPANTS: Nursing home physicians from the American Medical Directors Association (AMDA) Foundation Long-Term Care Research Network (n = 142), as well as other members of AMDA who were Certified Medical Directors (CMD) (n = 68) and members who were not CMD certified (n = 45). Response rates to the survey were 51%, 33%, and 23%, respectively. MEASUREMENTS: Physician and facility characteristics were queried. Responses to 12 items pertaining to diabetes management and 5 items pertaining to use of specific oral diabetes medications were evaluated in the context of 3 different patient profiles that reflected different combinations of functional and cognitive impairment. Responses were based on the physicians' perception of how they manage diabetes under these specified patient profiles. RESULTS: Responses from members of the Research Network indicated highly significant variability (P < .01) between the 3 patient profiles for all of the 12 management items. Ordering a special diet, monitoring lipid panel, and ordering routine ophthalmology was less likely for the patient profile with both functional and cognitive impairment (P < .01). These differences among the patient profiles for these 3 interventions were present in the responses from all 3 categories of physicians (Research Network, CMD, and non-CMD members of AMDA). There was no statistically significant variability among the 3 patient profiles for any of the 3 physician groups regarding the likelihood of using of any of the 5 classes of oral diabetic medications. Non-CMD physicians were more likely to have less NH experience; otherwise, there were no differences among the 3 physician groups. CONCLUSIONS: Nursing home physicians appear to alter the approach to diabetes management based on the functional and/or cognitive status of the patient. This was particularly true for those physicians who were members of the AMDA Foundation Research Network. These findings have implications for initiatives designed to guide clinical practice as well as efforts by regulatory bodies to evaluate appropriate care. Further research is needed to measure the actual impact of different approaches to diabetes management on relevant outcomes in this population.

Activities of Daily Living↗

PubMed1982

Cognition in Parkinson disease: an event-related potential perspective.

Auditory event-related potentials (ERP) elicited in a target detection stimulus paradigm and pattern-shift visual ERPs were studied in 20 male patients with idiopathic Parkinson disease (PD) and 20 age-matched normal controls. Patients showed significantly increased latencies for both the P200 and P300 components of the auditory ERP. Patients and controls showed no significant differences in latency of the visual ERP but patients showed significantly decreased amplitude. Only one of five neuropsychological measures, the Symbol Digit Modalities test (SDMT), showed a significant negative correlation with P300 latency. The significant association between the two measures that showed impairments in the PD patients (P300 latency and SDMT scores) suggested that these measures reflect a common, disrupted aspect of cognitive function in PD.

Aged↗

PubMed1995

Impaired mismatch negativity generation reflects widespread dysfunction of working memory in schizophrenia.

BACKGROUND: Impaired P300 (P3) generation is one of the most robust indices of brain dysfunction in schizophrenia. This study investigates the integrity of cognitive event-related potentials that precede P3 in an "oddball" paradigm to determine the earliest stages at which auditory information processing is impaired in schizophrenia. METHODS: Cognitive event-related potential components including mismatch negativity (MMN), N2, and P3 were recorded from subjects with chronic schizophrenia who were receiving medication (n = 20), from those who were withdrawn from drug treatment (n = 11), and from healthy volunteers (n = 11) during an auditory oddball paradigm. Recordings were made in both passive and active response conditions. The MMN, N2, and P3 amplitudes were compared across groups and the degree of MMN deficit was correlated with the degree of P3 reduction as a function of diagnostic group. RESULTS: Schizophrenic subjects showed severe impairments in the generation of MMN and N2 as well as P3. Across groups, the decrement in MMN amplitude correlated significantly with the decrement in P3 amplitude. There were no significant between-group differences in MMN topography. CONCLUSIONS: The present study demonstrates that the neurophysiological deficits associated with schizophrenia, as reflected in cognitive event-related potential generation, are pervasive, extending even to the level of the sensory cortex. Mismatch negativity indexes the functioning of an automatic alerting mechanism designed to stimulate individuals to explore unexpected environmental events. Dysfunction of this mechanism may contribute to the deficit state associated with schizophrenia.

Adult↗

PubMed2005

fMRI resting state networks define distinct modes of long-distance interactions in the human brain.

Functional magnetic resonance imaging (fMRI) studies of the human brain have suggested that low-frequency fluctuations in resting fMRI data collected using blood oxygen level dependent (BOLD) contrast correspond to functionally relevant resting state networks (RSNs). Whether the fluctuations of resting fMRI signal in RSNs are a direct consequence of neocortical neuronal activity or are low-frequency artifacts due to other physiological processes (e.g., autonomically driven fluctuations in cerebral blood flow) is uncertain. In order to investigate further these fluctuations, we have characterized their spatial and temporal properties using probabilistic independent component analysis (PICA), a robust approach to RSN identification. Here, we provide evidence that: i. RSNs are not caused by signal artifacts due to low sampling rate (aliasing); ii. they are localized primarily to the cerebral cortex; iii. similar RSNs also can be identified in perfusion fMRI data; and iv. at least 5 distinct RSN patterns are reproducible across different subjects. The RSNs appear to reflect "default" interactions related to functional networks related to those recruited by specific types of cognitive processes. RSNs are a major source of non-modeled signal in BOLD fMRI data, so a full understanding of their dynamics will improve the interpretation of functional brain imaging studies more generally. Because RSNs reflect interactions in cognitively relevant functional networks, they offer a new approach to the characterization of state changes with pathology and the effects of drugs.

Adult↗

PubMed2005

Cholinergic challenge in Alzheimer patients and mild cognitive impairment differentially affects hippocampal activation--a pharmacological fMRI study.

Pharmacological functional MRI (phMRI) examines the impact of pharmacologically induced neurochemical changes on brain function at a system level. The current phMRI study directly compared effects of cholinergic stimulation on brain function between patients with Alzheimer's disease and mild cognitive impairment, a disease stage preceding the development of Alzheimer's disease. Brain function during recognition of (un)familiar information was examined for changes after exposure to galantamine, a cholinesterase inhibitor used for treating memory deficits in Alzheimer's disease. Alzheimer patients [n = 18; age 74.5 years +/- 8.2; Mini-Mental State Examination (MMSE) 22.5 +/- 2.4] and patients with mild cognitive impairment (n = 28; mean age 73.6 +/- 7.5; MMSE 27.0 +/- 1.2) were scanned during face recognition under three different conditions: at baseline, and after acute (single dose) and prolonged exposure (5 days) to galantamine. Functional data were analysed in an event-related fashion. In both groups, acute exposure produced strong increases in brain activation (Z > 3.1). Prolonged exposure produced less strong effects that mainly involved decreases in activation (Z > 3.1). In mild cognitive impairment, acute exposure increased activation in posterior cingulate, left inferior parietal, and anterior temporal lobe. Prolonged exposure decreased activation in similar posterior cingulate areas, and in bilateral prefrontal areas. Effects were stronger for positive ('familiar') than for negative ('unfamiliar') decisions, indicating that the effect was specific to memory retrieval. In Alzheimer patients, acute exposure increased activation bilaterally in hippocampal areas, whereas prolonged exposure decreased activation in these areas. Effects were more pronounced for negative than for positive decisions, suggesting a preferential effect on memory encoding. Unique profiles of signal reactivity were found in a number of areas, including left inferior parietal lobe and left hippocampus proper. The reactivity of posterior cingulate and hippocampal structures to cholinergic challenge suggests a key role of the cholinergic system in the functional processes that lead to Alzheimer's disease. The differential response to cholinergic challenge in mild cognitive impairment and Alzheimer patients may reflect a difference in the functional status of the cholinergic system between both groups, which is in line with recent results showing a differential clinical response to cholinergic treatment.

Aged↗

PubMed1987

Is the matching familiar figures test a measure of cognitive style? A warning for users.

A probabilistic model of reflection-impulsivity as measured by the Matching Familiar Figures Test (MFFT) is presented and tested on 77 fourth graders. In testing the model two groups emerged, a random response group (n = 22) and a cognitive response group (n = 55), who use the evaluation process. Correlations among latencies, total errors, initial errors, school-scores, and IQs were compared for our total sample and the two groups. The correlation of MFFT latencies and errors disappeared for the random-response group and new correlations with errors appeared while the cognitive response group kept a statistically significant correlation of latencies with errors and no other error correlation was shown. This last group was classified by Kagan's median-split procedure showing that most reflective subjects kept their classification. Preliminary results suggest a reinterpretation of reflection-impulsivity literature, especially as related to the impulsive style.

Child↗

PubMed2003

Neural correlates of clinical symptoms and cognitive dysfunctions in obsessive-compulsive disorder.

Although results from neuropsychological and neuroimaging studies have postulated the involvement of the frontal lobe and the subcortical brain regions in the pathophysiology of obsessive-compulsive disorder (OCD), neuroimaging studies have provided little evidence that cognitive abnormalities in patients with OCD are related to dysfunctions in these areas. This study was designed to determine whether the clinical features and cognitive deficits of OCD might be taken to reflect frontal-subcortical dysfunction. Fourteen patients with OCD and 14 case-matched normal subjects completed clinical and cognitive evaluation, including four sets of neuropsychological tests that assessed the executive functions and visual memory. Cerebral glucose metabolic rates were measured by using positron emission tomography (PET) with 18F-fluorodeoxyglucose. Behavioral and PET data were analyzed using statistical parametric mapping for group differences and behavioral-metabolic correlates. The right orbitofrontal cortex showed increased metabolic activity and the left parieto-occipital junction showed decreased metabolic activity in patients. Metabolism in the right hippocampus, the left putamen and the right parietal region was associated with the severity of obsessive-compulsive symptoms. Correlations between metabolic rates and neuropsychological test scores in the prefrontal cortex and the putamen occurred only in the patient group. These results suggest that patients with OCD have distinct features of brain metabolic activities for performing cognitive tasks as well as presenting obsessive-compulsive symptoms. In particular, the frontal-subcortical circuits might mediate not only symptomatic expression but also cognitive expression in patients with OCD.

Adult↗

PubMed2000

Cognitive decline in women in relation to non-protein-bound oestradiol concentrations.

BACKGROUND: Previous studies have found no association between serum concentrations of total oestradiol and cognitive function, but these measurements may not reflect concentrations of hormone available to the brain. We tested the hypothesis that concentrations of non-protein-bound (free) and loosely bound (bioavailable) sex hormones are associated with cognitive function in older women. METHODS: We measured cognitive performance with a modified mini mental status examination (mMMSE) at baseline (1986-88) and 6 years later in 425 women (65 years or older). Concentrations of non-protein-bound and bioavailable oestradiol and total and non-protein-bound testosterone were measured by RIA in serum samples taken at baseline. FINDINGS: Initial cognitive scores did not differ by tertile of non-protein-bound oestradiol, bioavailable oestradiol, or testosterone. Cognitive impairment (a decrease of 3 points or more in mMMSE score) occurred in five (5%) of 94 women in the high tertile for non-protein-bound oestradiol and in 17 (16%) of 106 in the low tertile (odds ratio 0.3 [95% CI 0.1-0.8]). After adjustment for age, years of education, body-mass index, current oestrogen use, history of surgical menopause, and baseline mMMSE score, the odds ratio was 0.3 (0.1-0.9). The results were similar for bioavailable oestradiol (five [5%] vs 15 [15%]; adjusted odds ratio 0.3 [0.1-1.0]). There was no association between risk of cognitive impairment and serum testosterone. INTERPRETATION: Women with high serum concentrations of non-protein-bound and bioavailable oestradiol, but not testosterone, were less likely to develop cognitive impairment than women with low concentrations. This finding supports the hypothesis that higher concentrations of endogenous oestrogens prevent cognitive decline.

Aged↗

PubMed1983

Rheoencephalographic concomitants of cognitive engagement in nonpatients and schizophrenics. An exploratory study.

Noninvasive cranial impedance plethysmographic, or rheoencephalography (REG), characteristics are reported to be well correlated with cerebral blood flow. This paper reports an exploratory study, in which we recorded REGs from four locations over each hemisphere in 16 nonpatients and 16 medicated schizophrenics under four conditions: eyes closed, eyes open, and following performance of the Seashore Rhythms and Wisconsin Sorting Tests. REG (Jacquy F index) values were greater anteriorly than posteriorly under all conditions. F index differed regionally between card sorting and eyes open conditions. With card sorting, F values of nonpatients increased more in the left than right hemisphere; schizophrenics showed the reverse hemispheric effect. Card sorting performance scores were positively correlated with regional F index changes in nonpatients, but not in schizophrenics. The results suggest that the REG may reflect regional cerebral effects associated with cognition and psychopathology.

Adult↗

PubMed1982

Lateralization, physiognomic perception, and flexibility of cognitive control.

32 left-handed and 34 right-handed college educated women were administered a hemispheric lateralization task and measures of physiognomic perception and cognitive flexibility. Results supported the hypothesis that differing hemispheric lateralization patterns would be reflected in differing degrees of physiognomic perception and flexibility of cognitive control. The demonstrated relationships suggest possible structural parallels between hemispheric lateralization patterns and cognitive style. Results further suggest that ambilateralization, rather than reducing hemispheric efficiency, may be a more advantageous psychological organization for certain cognitive tasks.

Cognition↗

PubMed1994

Brain dynamics and hypnosis: attentional and disattentional processes.

This article reviews recent research findings, expanding an evolving neuropsychophysiological model of hypnosis (Crawford, 1989; Crawford & Gruzelier, 1992), that support the view that highly hypnotizable persons (highs) possess stronger attentional filtering abilities than do low hypnotizable persons, and that these differences are reflected in underlying brain dynamics. Behavioral, cognitive, and neurophysiological evidence is reviewed that suggests that highs can both better focus and sustain their attention as well as better ignore irrelevant stimuli in the environment. It is proposed that hypnosis is a state of enhanced attention that activates an interplay between cortical and subcortical brain dynamics during hypnotic phenomena, such as both attentional and disattentional processes, among others, are important in the experiencing of hypnosis and hypnotic phenomena. Findings from studies of electrocortical activity, event-related potentials, and regional cerebral blood flow during waking and hypnosis are presented to suggest that these attentional differences are reflected in underlying neurophysiological differences in the far fronto-limbic attentional system.

Attention↗

PubMed1998

Age differences in decision making: to take a risk or not?

A controlled laboratory experiment was used to assess the efficacy of the cognitive processes that underlie risk taking decision making in young and elderly people. Thirty-six participants took part in the study: half the subjects were elderly (mean age of 74) and the other half were young adults (mean age of 19). The elderly participants made equivalent decisions to those of the control young adults. Both age-groups of participants systematically and comparably changed their behavior as a function of risk levels. Furthermore, the elderly participants, relative to young adults, did not exhibit any slowing down in the speed of processing the information involved in making risk taking decisions, reflecting that healthy elderly people are cognitively apt to making risk taking decisions. Both age-groups took comparably less time on the easy trials (trials with either low or high levels of risk) and comparably more time on the difficult trials (trials with medium levels of risk).

Adolescent↗

PubMed1994

One-year follow-up of psychotherapy and pharmacotherapy for cocaine dependence. Delayed emergence of psychotherapy effects.

BACKGROUND: Neither the durability of brief ambulatory treatments for cocaine dependence nor the relative ability of psychotherapy vs pharmacotherapy to effect lasting change has been evaluated in well-controlled randomized trials. METHODS: We conducted a 1-year naturalistic follow-up of 121 ambulatory cocaine abusers who underwent psychotherapy (cognitive-behavioral relapse prevention or clinical management) and pharmacotherapy (desipramine hydrochloride or placebo) in a 2 x 2 design. Subjects were interviewed 1, 3, 6, or 12 months after the termination of a 12-week course of outpatient treatment. Eighty percent (n = 97) of the subjects who were randomized to treatment were followed up at least once. RESULTS: First, the effects of study treatments appeared durable over the follow-up; as for the full sample, measures of cocaine use indicated either improvement or no change over posttreatment levels. Second, abstinence during treatment was strongly associated with less cocaine use during follow-up. Third, random effects regression models indicated significant psychotherapy-by-time effects, suggesting a delayed improved response during follow-up for patients who received cognitive-behavioral relapse prevention compared with supportive clinical management. CONCLUSIONS: Our findings suggest a delayed emergence of the effects of cognitive-behavioral relapse prevention, which may reflect the subjects' implementation of the generalizable coping skills conveyed through that treatment. Moreover, these data underline the importance of conducting follow-up studies of substance abusers and other groups because delayed effects may occur after the cessation of short-term treatments.

Adaptation, Psychological↗

PubMed2006

Perceptual grouping in disorganized schizophrenia.

This study evaluated visual perceptual grouping in schizophrenia to test the hypothesis that the disorganization syndrome in schizophrenia is related to a deficit in cognitive coordination. Perceptual grouping was examined with three psychophysically well-controlled tasks in patients with disorganized schizophrenia (n=11), non-disorganized schizophrenia (n=24), psychotic disorders other than schizophrenia (n=31) and non-psychotic psychiatric disorders (n=35). These measures assessed processing of both concurrent and preceding stimulus context. Deficits in perceptual grouping were observed on all three tasks in disorganized schizophrenia patients. Dysfunctional perceptual grouping mechanisms produced both enhanced and impaired task performance suggesting that the pattern of performance observed was the result of a specific deficit in the grouping of stimulus elements. We interpret these data as further support for the hypothesis that the disorganization syndrome in schizophrenia reflects a widespread deficit in the cognitive coordination of contextually related stimuli, leading to dysfunctional grouping of stimulus features in vision, thought and language.

Adult↗

PubMed1975

Cognitive and personality factors associated with the double trapezium illusion.

76 pairs of 9- to 11-yr.-old twins (41 female, 35 male) who were discordant on the magnitude of error for the double trapezium illusion were given the Children's Personality Questionnaire and the Wechsler Intelligence Scale for Children (WISC). The Wilcoxon matched-pair signed-ranks test was used to determine whether the twins with relatively smaller magnitudes of error than their co-twins also manifested systematic differences on the personality factor scores and the WISC subtest scores. Among the female pairs, twins with smaller magnitudes of the illusion were relatively more stable (Factor C), more shrewd (Factor N), obtained higher scores on Similarities and Digit Span, and had longer reaction times before responding to the figures. Among the male pairs, similar trends were found but the differences were not as pronounced. The results are discussed in terms of Piaget's theory concerning children's deployment of attention and Kagan's reflective-impulsive dimension in children's cognitive judgments.

Child↗

PubMed2002

Material-specific deficits in "remembering" in patients with unilateral temporal lobe epilepsy and excisions.

A growing body of research suggests that "remembering" and "knowing" may be dissociable aspects of recognition memory. Cognitive theorists have argued that the former reflects conceptual processing and is based on distinctive memory traces whereas the latter is associated with perceptual analysis and reflects fluency of processing. Here, we investigate whether this framework can account for memory deficits observed following right or left temporal lobe damage, as suggested by Blaxton and Theodore [Brain and Cognition 35 (1997) 5]. Recognition memory for faces and words was examined in patients with unilateral temporal lobe epilepsy or excisions (TLE) and controls using the "remember-know" recognition paradigm. Participants studied items under conditions designed to enhance either conceptual processing or focus their attention on superficial aspects of the items. For controls, there was an increase in "remember" responses following conceptually-based encoding for both words and faces. This enhancement was eliminated in patients with left TLE for words and those with right TLE showed a diminished effect for faces. This pattern indicates an impairment in the ability to benefit from conceptual encoding that is specific to material preferentially processed by the damaged hemisphere. Furthermore, this effect was only observed for "remember" responses, which are based on the participants' ability to recollect specific contextual aspects of the original study experience. These data can be interpreted in relation to current theories of hippocampal function, which emphasize the critical role played by the hippocampus in relational memory formation and retrieval. We offer this as a novel interpretation of the "remember-know" literature.

Adult↗

PubMed2003

Perinatal asphyxia in the guinea pig leads to morphologic but not neurologic, cognitive, or behavioral changes.

BACKGROUND: In a recent publication, we described neurodegeneration along with neurotransmitter deficits and impaired differentiation in the guinea pig 3 months following severe perinatal asphyxia (PA). We were therefore interested in the clinical features in terms of neurology, cognitive functions, and behavior. METHODS: We tested the long-term effects of PA in an animal model, which in the rat are well documented and resemble the clinical situation. Examinations consisted of an observational battery for motor and reflex functions and the acoustic startle response setting. We tested cognitive functions in the multiple T-maze and evaluated behavior using the elevated plus maze and open field studies. RESULTS: No neurologic deficits were observed in the observational battery, including the acoustic startle response. Cognitive functions of memory and learning were not impaired in the multiple T-maze. In the open field and in the elevated plus maze, the system to test anxiety-related behavior, guinea pigs performed well. CONCLUSION: Our findings of patent neurology, cognitive functions, and behavior do not reflect the prominent morphologic findings of neurodegeneration. This is in agreement with corresponding studies on PA in the rat at the identical time point. We learned from this study that both test systems, although representing the standard in neuroscience, are either not sensitive enough or central nervous system lesions are clinically fully compensated.

Animals↗

PubMed1991

WAIS-R intrasubtest scatter in a chronic schizophrenic population: is it an attentional problem?

This study investigated the hypothesis that intrasubtest scatter on the WAIS-R is a measure of fluctuations in attention/concentration. Thirty-two chronic schizophrenic inpatients were administered the WAIS-R, the Mini-Mental State Examination, an attention task battery, and the Psychotic Inpatient Profile. Intrasubtest scatter correlated significantly with some attention measures. However, scatter was correlated more highly with cognitive aspects of mental status, Freedom from Distractibility, and observed psychotic behavior. Thus, intrasubtest scatter in this population appears to reflect a broader measure of the integrity of "cognitive state" and not merely a clinical indication of attention/concentration problems.

Adult↗