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PubMed2003

Comparable measures of cognitive function in human infants and laboratory animals to identify environmental health risks to children.

The importance of including neurodevelopmental end points in environmental studies is clear. A validated measure of cognitive function in human infants that also has a homologous or parallel test in laboratory animal studies will provide a valuable approach for large-scale studies. Such a comparable test will allow researchers to observe the effect of environmental neurotoxicants in animals and relate those findings to humans. In this article, we present the results of a review of post-1990, peer-reviewed literature and current research examining measures of cognitive function that can be applied to both human infants (0-12 months old) and laboratory animals. We begin with a discussion of the definition of cognitive function and important considerations in cross-species research. We then describe identified comparable measures, providing a description of the test in human infants and animal subjects. Available information on test reliability, validity, and population norms, as well as test limitations and constraints, is also presented.

Animals↗
PubMed2005

[Cognitive function among physically independent very old people in an urban community in Japan: the Itabashi Oldest-Old Study II].

This study was conducted to clarify the characteristics of cognitive function among physically independent very old people dwelling in an urban community in Japan. Five hundred and thirteen Old-Old (aged 75-84 years) and 168 Oldest-Old (aged 85-100 years) adults participated. We carried out the Mini-Mental State Examination (MMSE) for measuring cognitive functions in the elderly. Age-related differences in the total score and sub-scale scores of the MMSE were analyzed by sex using ANCOVA, controlling for education, vision and hearing problems. Mean MMSE scores for Old-Old and Oldest-Old males were 27.53 and 25.88, respectively, and those for Old-Old and Oldest-Old females were 27.77 and 24.98, respectively. Age-related differences in the MMSE total score between the Old-Old and Oldest-Old were observed in both sexes, suggesting that overall cognitive functions continue to decline over time in very old age. Age-related differences between the Old-Old and Oldest-Old in items measuring, registration, calculation and delayed recall were observed in both sexes, and in addition, time orientation, place orientation, delayed recognition, writing sentences, and copying figures were observed in females. These findings suggest that the faculties are those most sensitive to normal aging among very old individuals. There were no age group differences in five items: reverse spelling, naming objects, repeating a sentence, listening and obeying, and reading and obeying.

Activities of Daily Living↗
PubMed1993

Cognitive function. Survey of elderly persons living at home in rural Newfoundland.

We tested the cognitive function of elderly, community-dwelling residents in rural Newfoundland using the Canadian Mental Status Questionnaire. The prevalence of moderate and severe cognitive impairment was 9.3%. Physicians in the community had recognized those with severe impairment, but had not recognized any of those with moderate impairment. Cognitive function testing should be part of the periodic health examination of older patients.

Aged↗
PubMed2000

Development of simple cognitive function measures in a community dwelling population of elderly in Spain.

OBJECTIVE: To develop and assess the consistency and validity of simple cognitive function measures for an elderly population with low levels of formal education for use in a longitudinal study of dementia. METHODS: Data were from the population longitudinal study 'Growing old in Leganés' (Spain). In 1993, a random sample of 1540 people over 65 was drawn from the City Roll of Leganés from which 1284 (83%) were successfully interviewed. Measures of memory and orientation were based on the SPMSQ (Short Portable Mental Status Questionnaire), the Barcelona test and the short story from EPESE (Established Populations Epidemiologic Studies of the Elderly). Non-response to a test item was coded as an error. Internal consistency was assessed by factor analysis and Cronbach's alpha. Construct validity was examined with multiple linear regressions of the proposed measurements on variables chosen from the existing literature on cognitive function. RESULTS: Two factors, memory and orientation, emerged from the factor analysis. Internal consistency of the proposed indexes for memory and orientation was acceptable. Memory and orientation scores were summed into one summary index of cognition. Associations between covariates and both cognitive indexes were in the expected direction. Among those highly functional, orientation was influenced by illiteracy due to higher error rates in the time orientation items based on dates; however, memory and summary scores were not significantly different by literacy status. A large proportion of the variance in IADL was explained by the memory and orientation measures. CONCLUSION: The memory and orientation indexes are valid and reliable measurements of cognitive function for use in a population of community dwelling elderly with low levels of formal education and high rates of illiteracy.

Aged↗
PubMed2003

[The effect of cerebrolysin on cognitive functions in childhood autism and in Asperger syndrome].

Nineteen children with childhood autism and 8 with Asperger's syndrome aged 2-8 year, were treated with cerebrolysin (CL) in inpatient clinic. All the patients received 10 microinjections (intramuscularly and perinervously) of 0.1 ml CL daily during 5 days. Clinical study was combined with device estimation of cognitive functions and communicative skills. CL therapy resulted in improvement of cognitive functions (expressive and receptive speech, fine motoring, playing). Positive effects were revealed in all the patients with Asperger's syndrome and in 89% of the patients with childhood autism. Any negative effects were not found. With regard to cognitive functions development, therapeutic efficacy proved to be more pronounced in the patients with Asperger's syndrome as compared to childhood autistic group (p < 0.005).

Amino Acids↗
PubMed2003

Mesial temporal lobe epilepsy and hippocampal sclerosis: cognitive function assessment in Hispanic patients.

PURPOSE: The goal of this study was to assess the cognitive function status in patients with mesial temporal lobe epilepsy and hippocampal sclerosis (TLE+HS) to determine their cognitive function profile and to correlate material-specific memory deficits with HS laterality diagnosed by MRI. METHODS: Seventy-one patients were assessed with a neuropsychological protocol that includes IQ, attention, handedness, verbal memory, visual memory, language, and the executive function. chi(2) and correlation tests were used. RESULTS: Memory impairment was found in 46 patients (66%): patients without any memory deficit (n=25), patients with verbal memory deficit (n=21), patients with visual memory deficit (n=17), patients with deficit for both types of memory (n=8). Correlation between MRI lesion and memory was 66%. Language was impaired in 33 patients (46%). Eighteen patients (25%) had a deficit of the executive function. CONCLUSIONS: Patients with TLE+HS presented with a deficit in material-specific episodic memory correlating in large proportion with HS lateralization. We also found language and executive function impairments.

Adult↗
PubMed2004

Endogenous glucocorticoids are essential for maintaining prefrontal cortical cognitive function.

Glucocorticoid hormones are important in the maintenance of many brain functions. Although their receptors are distributed abundantly throughout the brain, including the prefrontal cortex (PFC), it is not clear how glucocorticoid functions, particularly with regard to cognitive processing in the PFC. There is evidence of PFC cognitive deficits such as working memory impairment in several stress-related neuropsychiatric disorders, including depression, schizophrenia, and Parkinson's disease. Disruption of the hypothalamo-pituitary-adrenal (HPA) system, which is characterized by attenuated glucocorticoid negative feedback, is also observed. In rats, chronic stress induces working memory impairment as a result of decreased dopaminergic transmission in the PFC. These chronically stressed rats also show HPA disruption; this is caused in part by a reduced glucocorticoid response in the PFC. These findings implicate reduced glucocorticoid actions in working memory impairment. In the present study, we examined the effects of the suppression of endogenous glucocorticoids by adrenalectomy (ADX) on working memory in rats and explored the involvement of PFC dopaminergic activities in memory. The ADX impaired working memory, decreased dopamine release, and upregulated D1 receptors in the PFC. These dysfunctions were prevented by corticosterone replacement that reproduced normal physiological plasma levels, indicating that suppression of glucocorticoids causes these dysfunctions. Moreover, the ADX-induced working memory impairment was ameliorated by intra-PFC infusions of a D1 receptor agonist, SKF 81297. Thus, suppression of glucocorticoids impaired working memory through a D1 receptor-mediated hypodopaminergic mechanism in the PFC. This finding indicates that endogenous glucocorticoids are essential for maintaining PFC cognitive function and suggests that HPA disruption contributes to PFC cognitive deficits.

Adrenalectomy↗
PubMed1999

Lifetime cognitive function and timing of the natural menopause.

BACKGROUND: There is evidence that ovarian steroids influence both reproductive aging and neural development. OBJECTIVE: We investigated the relationship between menopause and lifetime cognitive function in a prospective birth cohort study. METHODS: Participants were 1,572 women enrolled in the Medical Research Council National Survey of Health and Development (the British 1946 birth cohort). By age 50, 245 women were postmenopausal, 724 were pre- or perimenopausal, 288 had had a hysterectomy or bilateral oophorectomy, and 291 women had started taking hormone replacement therapy (HRT) before their menopause. The remaining 24 women, for various reasons, could not be classified into any of these groups. We investigated the association between cognitive function at ages 8, 11, 15, 26, and 43 years and menopause timing using Cox proportional hazard models, censoring for hysterectomy and bilateral oophorectomy, and initially for HRT use. The effect of including HRT use before menopause as an additional outcome was investigated using a competing risks analysis. RESULTS: Higher cognitive scores were associated with later menopause. The effect was strongest in childhood. This finding could not be explained by a variety of potential confounders, including early social background, physical development, education, adult social class, parity, smoking, and alcohol consumption. CONCLUSIONS: Childhood cognitive function is related to timing of the natural menopause. Both may be influenced by ovarian steroids across the life-span.

Adolescent↗
PubMed1992

Cognitive function--victim of disease or hostage to treatment?

In persons suffering from epilepsy, cognitive functioning may be compromised for various reasons, including--first and foremost--the learning and behavioral effects of the conditions causing the epilepsy. In addition, the epilepsy itself may cause changes in the nervous system through the metabolic and excitotoxic effects of the seizures and the neurotransmitter elements involved at the membrane level. The effect of the treatment modality, be it pharmacologic or surgical, may also play havoc with cognitive function. The neurobehavioral effects of antiepileptic drugs, although probably less important with the newer agents than in the past, must be considered, especially in polypharmacy, as recent reports have indicated. With increasing data, the effects of various surgical procedures on the cognitive elements of human behavior are becoming better recognized.

Anticonvulsants↗
PubMed1998

Estrogen therapy in postmenopausal women: effects on cognitive function and dementia.

CONTEXT: Several studies have suggested that estrogen replacement therapy in postmenopausal women improves cognition, prevents development of dementia, and improves the severity of dementia, while other studies have not found a benefit of estrogen use. OBJECTIVE: To determine whether postmenopausal estrogen therapy improves cognition, prevents development of dementia, or improves dementia severity. DATA SOURCES: We performed a literature search of studies published from January 1966 through June 1997, using MEDLINE, manually searched bibliographies of articles identified, and consulted experts. STUDY SELECTION: Studies that evaluated biological mechanisms of estrogen's effect on the central nervous system and studies that addressed the effect of estrogen on cognitive function or on dementia. DATA EXTRACTION: We reviewed studies for methods, sources of bias, and outcomes and performed a meta-analysis of the 10 studies of postmenopausal estrogen use and risk of dementia using standard meta-analytic methods. DATA SYNTHESIS: Biochemical and neurophysiologic studies suggest several mechanisms by which estrogen may affect cognition: promotion of cholinergic and serotonergic activity in specific brain regions, maintenance of neural circuitry, favorable lipoprotein alterations, and prevention of cerebral ischemia. Five observational studies and 8 trials have addressed the effect of estrogen on cognitive function in nondemented postmenopausal women. Cognition seems to improve in perimenopausal women, possibly because menopausal symptoms improve, but there is no clear benefit in asymptomatic women. Ten observational studies have measured the effect of postmenopausal estrogen use on risk of developing dementia. Meta-analysis of these studies suggests a 29% decreased risk of developing dementia among estrogen users, but the findings of the studies are heterogeneous. Four trials of estrogen therapy in women with Alzheimer disease have been conducted and have had primarily positive results, but most have been small, of short duration, non-randomized, and uncontrolled. CONCLUSIONS: There are plausible biological mechanisms by which estrogen might lead to improved cognition, reduced risk for dementia, or improvement in the severity of dementia. Studies conducted in women, however, have substantial methodologic problems and have produced conflicting results. Large placebo-controlled trials are required to address estrogen's role in prevention and treatment of Alzheimer disease and other dementias. Given the known risks of estrogen therapy, we do not recommend estrogen for the prevention or treatment of Alzheimer disease or other dementias until adequate trials have been completed.

Alzheimer Disease↗
PubMed1991

Reversed lateralization of cognitive functions in right handers. Exceptions to classical aphasiology.

Most current and past research on the cerebral organization of cognitive functions has presupposed certain specialized hemisphere operations. At least for right handers, language and praxis are to be organized in the left hemisphere, while affective prosody, configurational spatial capacity, and global attention are lateralized in the right hemisphere. Deviations from these presuppositions, as in crossed aphasics and perhaps left handers, are generally considered to be 'exceptions' and either to disprove the rules or to be irrelevant to the rule. We report 4 very 'exceptional' cases, right handers with almost entirely reversed lateralization of functions. Analysis of the intrahemispheric relationships between functions suggests that there may be a specific neurobiology to the interrelationships between and among cognitive functions, handedness, and the intrahemisphere localization of the function.

Adult↗
PubMed1999

Cognitive functioning in people with epilepsy plus severe learning disabilities: a systematic analysis of predictors of daytime arousal and attention.

In spite of the high prevalence of epilepsy and the importance of preserving cognitive function in people with learning disabilities, this population has received relatively little research attention. This study sets out systematically to investigate possible predictive factors of inter-ictal states of arousal and attention. The daytime function of 28 people with epilepsy and severe learning disabilities was assessed by performance on a two-choice reaction time vigilance task, behavioural analysis of time-sampled video recordings taken in naturalistic settings, and carer ratings on visual analogue scales. This methodology yielded eight discrete functional measures, from which two further index measures were derived after principal components analysis. A range of clinical and psychosocial assessments was completed and subjects had 36 hour ambulatory EEG and sleep EEG monitoring. Regression models identified significant predictors of cognitive function from a range of potential explanatory variables i.e. demographic, clinical, pharmacological, background EEG rhythms and sleep parameters. Results indicated that greater severity of learning disability, longer bedtime periods, poor sleep efficiency, frequent seizures and antiepileptic drug polytherapy were significant predictor variables. Explained variance (adjusted R2) was greater than 50% for six of 10 outcome variables (range up to 85%). Furthermore, significant regression equations (P < 0.05) were obtained for all but one variable. Thus, these results appear reasonably robust. Results support an interactional model of daytime arousal and attention in people with epilepsy plus severe learning disabilities. Inter-ictal cognitive function appears to be mediated by a combination of organic, circadian (sleep wake), clinical and pharmacological factors.

Adolescent↗
PubMed2001

Iron therapy for improving psychomotor development and cognitive function in children under the age of three with iron deficiency anaemia.

BACKGROUND: Iron deficiency and iron deficiency anaemia (IDA) are common in young children. It has been suggested that the lack of iron may have important effects on children's psychomotor development and cognitive function. OBJECTIVES: To determine the effects of iron therapy on psychomotor development and cognitive function in iron deficient children less than 3 years of age. SEARCH STRATEGY: The following databases were searched: COCHRANE LIBRARY (2000 ISSUE 4) MEDLINE (1966-August 2000) EMBASE (1980-August 2000) Latin American Database (LILACS) PsycLIT Journal articles (1974-August 2000) PsycLIT Chapters and Books (1987-August 2000) The references of identified trials and of important review articles were scrutinised. Citation searches on trials from the primary search were performed within the Science Citation Index. Key authors were contacted. SELECTION CRITERIA: Studies were included if children less than 3 years of age with evidence of iron deficiency anaemia were randomly allocated to iron or iron and vitamin C versus a placebo or vitamin C alone and assessment of developmental status or cognitive function was carried out using standardised tests by observers blind to treatment allocation. DATA COLLECTION AND ANALYSIS: Abstracts and titles of studies identified on searches of electronic databases were read to determine whether they might meet the inclusion criteria. Full copies of those possibly meeting these criteria from electronic or other searches were assessed by two independent reviewers. Differences of opinion about suitability for inclusion were resolved by discussion. Data were analysed separately depending on whether participants had iron assessments were performed within one month of beginning iron therapy or later. MAIN RESULTS: Five trials, including 180 children with IDA, examined the effects of iron therapy on measures of psychomotor development between 5 and 11 days of commencement of therapy. Data from four trials could be pooled. The pooled difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups was -3.2 (95%CI -7.24, 0.85) and in Bayley Scale MDI, 0.55 (95% CI -2.84, 1.75). Two studies, including 160 randomised children with IDA, examined the effects of iron therapy on measures of psychomotor development more than 30 days after commencement of therapy. Aukett et al reported the mean number of skills gained after two months of iron therapy, using the Denver test. The intervention group gained 0.8 (95% CI -0.18, 1.78) more skills on average than the control group. Idjrandinata et al reported that the difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups after 4 months was 18.40 (95%CI 10.16, 26.64) and in Bayley Scale MDI, 18.80 (95% CI 10.19, 27.41). REVIEWER'S CONCLUSIONS: There is no convincing evidence that iron treatment of young children with IDA has an effect on psychomotor development discernable within 5-11 days. The effect of longer term treatment remains unclear but the data would be compatible with clinically significant benefit. There is urgent need for further randomised controlled trials with long term follow up.

Anemia, Iron-Deficiency↗
PubMed2004

Natural oligomers of the amyloid-beta protein specifically disrupt cognitive function.

A central unresolved problem in research on Alzheimer disease is the nature of the molecular entity causing dementia. Here we provide the first direct experimental evidence that a defined molecular species of the amyloid-beta protein interferes with cognitive function. Soluble oligomeric forms of amyloid-beta, including trimers and dimers, were both necessary and sufficient to disrupt learned behavior in a manner that was rapid, potent and transient; they produced impaired cognitive function without inducing permanent neurological deficits. Although beta-amyloidosis has long been hypothesized to affect cognition, the abnormally folded protein species associated with this or any other neurodegenerative disease has not previously been isolated, defined biochemically and then specifically characterized with regard to its effects on cognitive function. The biochemical isolation of discrete amyloid-beta moieties with pathophysiological properties sets the stage for a new approach to studying the molecular mechanisms of cognitive impairment in Alzheimer disease and related neurodegenerative disorders.

Amyloid beta-Peptides↗
PubMed1995

Stress and cognitive function.

Stress affects cognition in a number of ways, acting rapidly via catecholamines and more slowly via glucocorticoids. Catecholamine actions involve beta adrenergic receptors and also availability of glucose, whereas glucocorticoids biphasically modulate synaptic plasticity over hours and also produce longer-term changes in dendritic structure that last for weeks. Prolonged exposure to stress leads to loss of neurons, particularly in the hippocampus. Recent evidence suggests that the glucocorticoid- and stress-related cognitive impairments involving declarative memory are probably related to the changes they effect in the hippocampus, whereas the stress-induced catecholamine effects on emotionally laden memories are postulated to involve structures such as the amgydala.

Animals↗
PubMed2005

Does cognitive function in older adults with hearing impairment improve by hearing aid use?

In the present study, the effects of hearing aid use by hearing-impaired older individuals on different aspects of cognitive function, such as memory, attention, executive functioning, and processing speed, were investigated. Fifty-six participants (mean age = 72.5) who were fitted with hearing aids were compared with 46 control participants (mean age = 74.5) with an equivalent hearing impairment, but who were not fitted with a hearing aid. After a dual baseline measurement and fitting of the hearing aids, all participants were assessed again with neurocognitive tests after 12 months. While the participants with hearing aids had improved aided hearing thresholds, they did not demonstrate an improved performance on the cognitive tests compared to the controls. Thus improved hearing did not improve cognitive functioning. These findings may suggest that hearing aid use only restores impairments at the level of the sensory organ, but does not affect the central nervous system and, as a consequence, cognitive functioning.

Aged↗
PubMed2005

[Effects of thyroid hormone on cognitive function in rats with chronic cerebral ischemia].

OBJECTIVE: To study the characteristics of cognitive dysfunction in rats with chronic cerebral ischemia and the effects of thyroid hormone on the rats' cognitive function. METHODS: Thirty-one male SD rats were randomly allocated into normal control group (n=12), operation group (with bilateral carotid artery ligation and examined 5 weeks later, n=6), acute phase treatment group (APT, with bilateral carotid artery ligation and intragastric administration of thyroid hormone at 20 mg once daily for 5 weeks starting from the day of operation, n=7) and chronic phase treatment group (CPT, with the operation and thyroid hormone administration in an identical manner started from the sixth week following the operation, n=6). Morris water maze test was performed at the end of experiment. One-way ANOVA was used to estimate the differences in the learning and memory functions of the rats using SPSS10.0 for Windows. RESULTS: The average latent period of the operation group was significantly prolonged in comparison with that of the other groups (P<0.05) in spatial orientation test. The probe time (time spent in the quadrant where the platform was once situated) of normal control was much shorter than those of the operation, APT and CPT groups in spatial probe test (P<0.05), and the operation group had the poorest score. The average latent period of the operation and CPT was longer than that of the other groups (P<0.05) in working-memory task (P<0.05), and the operation group again had the poorest score. CONCLUSION: Spatial cognitive function is totally damaged in rats with chronic cerebral ischemia, and learning can not induce the formation long-term memory because of short-term memory damage. Thyroid hormone may lessen but can not fully repair the damage of the cognitive dysfunction resulting from chronic cerebral ischemia, and early intervention with thyroid hormone may be beneficial for chronic cerebral ischemia.

Animals↗