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Trajectories of functional impairment in later life.

Functional impairment trajectories in late adulthood over a decade are characterized using the Longitudinal Retirement History Study (LRHS) data set. Non-linear patterns of age-related increase in impairment are documented with longitudinal data. Subsets of panelists from the initial large, nationally representative probability sample of employed males and unmarried employed females (N = 11,000) also exhibit differential non-linear trajectories of impairment by sex, income, and educational attainment. Concurrent analysis of the relationship over a decade among sex, SES, and functional impairment suggests that in health research, both sex and SES are broad proxy variables whose usefulness for understanding health outcomes and for policy analysis would be enhanced by the specification of components.

Activities of Daily Living↗

Laterality in functional brain imaging studies of schizophrenia.

Brain laterality in schizophrenia has been examined through the application of functional neuroimaging methods. These methods have included the 133Xenon technique for measuring cerebral blood flow (CBF); positron emission tomography for assessing rates of glucose metabolism, CBF, and neuroreceptor functioning; single photon emission computerized tomography for studying CBF and neuroreceptors; and functional magnetic resonance imaging for measuring changes attributable to CBF. This article highlights the application of this technology in schizophrenia research, emphasizing more recent studies that have evaluated hemispheric differences. There is evidence for lateralized abnormalities in some studies that have examined this dimension. In general, the results implicate abnormalities in left hemispheric activity. Recent advances in basic and clinical neuroscience provide an opportunity for focused application of functional imaging in neurobiological studies of schizophrenia.

Brain↗

Pulmonary function measures as predictors and correlates of cognitive functioning in later life.

The relation between pulmonary function and cognitive functioning was investigated in a cohort of 3,036 Japanese-American men living in Hawaii. Pulmonary function, as indicated by forced expiratory volume in 1 second (FEV1), was measured at the baseline examination from 1965 to 1968. Cognitive function was assessed by the Cognitive Abilities Screening Instrument (CASI) test at least 23 years later (1991-1993). Baseline FEV1 was significantly correlated with follow-up CASI score (r = 0.22, p = 0.0001). Although the strength of the association was reduced by controlling for the effects of other factors, stepwise multiple linear regression showed that FEV1 during middle age was a significant predictor of CASI in later life, after taking into account the effects of age, education, stroke, sedentary job activity, nonmanual occupation, height, generation, and Japanese speaking ability. The mean CASI value was significantly greater for men whose FEV1 exceeded 2.8 liter compared with those whose FEV1 levels were in the lowest (<2.5 liters) quartile. Furthermore, the test on the effect of interaction between FEV1 and age was statistically significant (p = 0.0024), with subjects less than 55 years of age at the baseline examination showing a stronger direct association of FEV1 with CASI than the men aged 55 or older. These findings suggest that pulmonary function impairment may be associated with cognitive function impairment in later life.

Aged↗

Relationship between sex-role identity and functional cerebral lateralization.

The present study examined the relationship between sex-role identity (SRI) and functional cerebral lateralization (FCL) in right-handed males. Two tasks (figure task and location task) were used to assess FCL. The figure task required the identification of shape stimuli, while the location task involved identification of the position of stimuli. SRI was assessed by the Bem Sex Role Inventory (BSRI). Males with higher masculine scores in the BSRI indicated greater differences in the reaction time between right and left visual-fields in the location task. This finding suggests that males with higher masculinity in SRI might have greater FCL.

Adult↗

Instability in functional motor laterality of children and adolescents with endogenous psychosis and predominantly motor disturbances.

A group of eight unmediated right-handed children and adolescents with endogenous psychosis and predominantly motor disturbances and two right-handed control groups (6 healthy subjects and 10 patients with different psychiatric diseases) were investigated with the help of a tapping-test series. The most important finding was related to differences in the stability of functional motor laterality between controls and psychotics. Stability of instability in functional motor laterality was identified by referring to the standard deviation (SD) of percentile right-left tapping differences calculated for each subject for the various parts of the tapping-test series. The high SDs in psychotics, in contrast to the low SDs in both control groups, point to increased variations or instabilities in the functional superiority of the preferred hand. Instability in functional motor laterality in this test is considered characteristic of this subgroup of patients, and may be due to a partial relapse to a lower hierarchical stage of handedness.

Adolescent↗

Contrasting infant predictors of later cognitive functioning.

The predictive power of early visual attention in terms of later cognitive functioning was compared to standard developmental test scores and further early predictors of later development. In a longitudinal study of 226 infants at risk visual attention in a habituation-dishabituation paradigm was assessed at 3 months and cognitive development was measured at 3, 24 and 54 months. The results indicated that response decrement and response recovery measures are related to cognitive outcome in later childhood, but failed to support their superiority over standard developmental test scores or early biological and psychosocial predictors of later IQ. Methodological shortcomings of previous studies and theoretical weaknesses of the habituation concept were discussed as a possible explanation.

Attention↗

Performance of the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) in multicenter clinical trials.

The Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) is a 10-item functional inventory which was devised for use in therapeutic trials in ALS. Each item is rated on a 0-4 scale by the patient and/or caregiver, yielding a maximum score of 40 points. The ALSFRS assesses patients' levels of self-sufficiency in areas of feeding, grooming, ambulation and communication. Rotated factor analysis of the ALSFRS found that the rating items group logically and consistently into four categories. The ALSFRS has been validated both cross-sectionally and longitudinally against muscle strength testing, the Schwab and England ADL rating scale, the Clinical Global Impression of Change (CGIC) scale, and independent assessments of patient's functional status. In this report, we use the data provided by the placebo patients who participated in the ALS CNTF Treatment Study (ACTS) to demonstrate the robustness, test-retest reliability and consistency of the ALSFRS as employed in a large, multicenter clinical trial.

Amyotrophic Lateral Sclerosis↗

Cognitive and psychosocial functioning of pediatric hematopoietic stem cell transplant patients: a prospective longitudinal study.

A prospective longitudinal study of cognitive and psychosocial functioning in pediatric hematopoietic stem cell transplant (HSCT) patients was conducted on three occasions: pre-HSCT, 1 year post-HSCT, and 2 years post-HSCT. In contrast to the previous hypothesis that cognitive declines would occur as a result of HSCT treatment, it was hypothesized that (1) global cognitive functioning (IQ scores), as well as specific areas would remain stable over time; (2) pre-transplant functioning would be predictive of later functioning; and (3) age would be negatively related to cognitive functioning. Based on previous research it was further hypothesized: that (4) while declines in psychosocial functioning might be seen at 1 year, functioning would improve by 2 years. 153 children and adolescents were evaluated pre-HSCT and at 1 year, with 2 year data available for 74 children. Longitudinal analyses of Wechsler IQ data were completed on 100 children (longitudinal exact test) and 52 children (repeated measures analysis of variance. Results of cognitive assessment indicated (1) stability of IQ scores over time; and (2) that the strongest predictor was pre-HSCT cognitive functioning. Psychosocial assessment results indicated: (1) a low prevalence of behavioral and social problems; (2) stability in functioning over time; (3) pre-HSCT functioning strongly predictive of later functioning.

Adolescent↗

Mapping lateralization of click trains in younger and older populations.

The main purpose of this study was to describe and compare lateralization of earphone-presented stimuli in younger and older individuals. Lateralization functions, relating perceived location to either interaural time differences (ITDs) or interaural level differences (ILDs) were determined for 78 subjects, aged 21-88 years, who responded by pressing one of nine keys to indicate the perceived location of the stimulus. All subjects were healthy, without any history of hearing loss or ear surgery and within the normal pure tone audiometric range for their age group. Interaural pure tone and click thresholds did not differ by more than 5 dB across ears. The ILD lateralization functions, ranging from 10 dB favoring the left ear to 10 dB favoring the right ear were linear. In contrast, the ITD lateralization functions were S-shaped with a clear linear component ranging from 750 micros favoring one ear to 750 micros favoring the other ear and with an asymptote from 750 micros to 1 ms. The same general shape of the ITD and ILD lateralization functions was found at all ages, but the linear slope of the ITD lateralization function became shallower with age. The ability to discriminate midline-located click trains (ITD and ILD=0) from ITD-lateralized click trains deteriorated with age, while the comparable ability to discriminate ILD-lateralized click trains did not change significantly with age. The data support two general conclusions. First there seems to be an overall reduction in the range of ITD-based lateralization due to aging. Second, there is a greater reduction in sensitivity due to aging in changes from the perceived midline position (ITD and ILD=0) when ITD is manipulated than when ILD is manipulated.

Acoustic Stimulation↗

[Functional brain lateralization in children: developmental theories and implication for developmental diseases].

The functional specialization of each hemisphere in adults is now well accepted. Neuropsychology of hemispheric functioning in young children is a more debatable issue and must take into account additional factors such as development and maturation, characterized by complex changes in anatomy and organization. The first part of this review describes the theory behind the development of the functional organization of the brain. Second, we discuss data regarding brain lesions in children with brain damage and with normal development. We comment on the concept of plasticity and the critical period. We also discuss the neurobiological processes underlying the functional organization of the brain in the model of developmental disorders in children. We chose three disorders involving the left hemisphere (developmental dysphasia), both hemispheres (benign rolandic epilepsy) or the right hemisphere (congenital hydrocephalus) in order to examine their relationship to a specific hemispheric functional organization. We used classic neuropsychological tests such as the dichotic listening task, the dichaptic palpation and the time-sharing paradigm. The patterns observed in each pathology are discussed in light of data obtained in children with brain lesions.

Child Development↗

Hemispheric differences in temporal resolution.

A review of the relevant clinical and experimental literature gives the conclusion that the cerebral hemispheres differ in temporal resolution of input, with the language-dominant hemisphere showing finer acuity. This conclusion is supported by evidence from performance of patients with unilateral brain damage on tests of temporal resolution, performance of developmental dyslexics on similar tasks, and left-right sensory field differences in temporal acuity in normal human subjects. While it is unlikely that a hemispheric difference in temporal resolution is sufficient to give a complete account of lateralized functions, such attempts to show more primitive physiological differences between the hemispheres are more likely to be fruitful than attempts which differentiate the hemispheres in terms of higher-order psychological functions.

Aphasia↗

Unilateral forced nostril breathing affects dichotic listening for emotional tones.

Unilateral forced nostril breathing (UFNB) through the left nostril is associated with enhanced spatial abilities, whereas UFNB through the right nostril is associated with enhanced verbal abilities. However, the effects of UFNB on standard tasks of laterality (e.g., dichotic listening) are unknown. This study employed dichotic listening for word targets, which typically exhibits a right ear advantage (REA), and dichotic listening for emotional targets, which typically exhibits a left ear advantage (LEA). Participants were asked to breathe either through their dominant nostril (congruent UFNB) or to breathe through their non-dominant nostril (incongruent UFNB) for the entire testing session. There was a significant three-way interaction between the type of dichotic listening task, nostril dominance, and nostril assignment, with the expected REA for word targets and the expected LEA for emotional targets-with one exception. Right nostril dominant participants assigned to the congruent condition exhibited an LEA for emotional targets (p < .05). The other three groups exhibited the expected LEA/right hemisphere advantage for the detection of emotional targets and all groups exhibited the expected REA/left hemisphere advantage for detection of word targets. As such, possible bias induced by tactile stimulation of the contralateral face cannot account for these results. Thus, our data are consistent with a selective enhancement of right hemispheric lateralized functions by right nostril UFNB.

Acoustic Stimulation↗

Cerebral dominance and asynchrony between bimanual two-dimensional movements.

The asynchrony of bimanual movements was investigated. Right- and left-handers traced simple geometrical patterns (ellipses) continuously with both hands. All combinations of the direction of rotation in each hand were executed at different rhythms. Geometrically, performances were largely independent of manual dominance. However, by comparing the passage times at homologous positions, the authors found that the dominant hand led the nondominant one by about 25 ms. The asynchrony was affected by neither movement type nor rhythm. The variability of the asynchrony varied along the trajectory, with well-defined maxima and minima. The variability profiles for movements that engaged homologous muscles differed markedly from those that engaged nonhomologous muscles. The authors discuss the hypothesis that bimanual periodic movements are timed by a lateralized functional module and asynchrony is due to the necessity of transmitting time-keeping information to the other hemisphere.

Adult↗

Determination of cognitive hemispheric lateralization by "functional" transcranial Doppler cross-validated by functional MRI.

BACKGROUND AND PURPOSE: Changes of blood flow velocity in the right and left middle cerebral artery (MCA) induced by cognitive demands are detectable by means of "functional" transcranial Doppler sonography (fTCD). Functional MRI (fMRI) is an alternative method for mapping brain activity. The purpose of this study was to determine whether fTCD can detect hemispheric lateralization and to cross-validate fTCD with fMRI. METHODS: Bilateral continuous MCA monitoring of 14 healthy, right-handed subjects with TCD was performed while the subjects underwent a visuospatial task, and the hemispheric blood flow velocity shift was calculated. Identical stimulus and response patterns were used in fMRI. Blood oxygenation level-dependent fMRI was performed with the use of a gradient-echo echo-planar sequence on a 1.5-T scanner. Statistical maps were computed on a voxel-by-voxel basis, hemispheric ratios for activated pixels were computed, and a group study was performed separately for the male and female subgroups. RESULTS: Statistical analyses (t test) showed a significantly higher mean peak blood flow velocity increase (P<0.05) of the right MCA (111.3+/-7.0%) compared with the left MCA (107.1+/-6.1%). fMRI demonstrated bilateral activation in the superior parietal lobulus (Brodmann area 7) with a right/left ratio of 1.95. Concordant differences between the female and male subgroups could be visualized with both methods. CONCLUSIONS: Both methods succeeded in discriminating a blood flow shift to the right hemisphere induced by a complex cognitive visuospatial task. fMRI cross-validates the findings of fTCD. Our study suggests that fTCD can investigate the close relationship between brain activity and blood flow and lateralize higher cognitive functions reliably.

Adult↗

Cerebral dominance, sex, and callosal size in MRI.

We measured the MRI area of corpus callosum in 104 normal adults, 51 men, 53 women, 52 right- and 52 left-handers. There were no significant sex or handedness differences. Callosal areas did not correlate with brain size nor with measures of lateralization for hand performance, dichotic listening, or visual field preference. The results are contrary to the notion of increased callosal connectivity in left-handers, women, or individuals with less-lateralized function.

Adolescent↗

Hemispheric differences in variability of fissural patterns in parasylvian and cingulate regions of human brains.

We have determined different patterns of fissurization in Broca's area, the gyrus of Heschl, the planum temporale, the inferior parietal lobe, and the cingulate sulcus. Such patterns were asymmetrically distributed, indicating increased folding on the left side in most cases. More folding can sometimes be related to a larger cortical area, resulting in increased processing capacities in the respective brain region. Furthermore, the brain regions associated with the asymmetrical sulci are involved in lateralized functions. Of special interest are the asymmetries observed in regions corresponding to the inferior parietal lobe (the accessory postcentral sulcus and the intraparietal sulcus), which, according to recent studies, is involved in linguistic working memory. We did not detect a tendency of distinct fissurization patterns in a given brain region to be associated with specific patterns in other fissures, indicating that the different fissure types develop independently in each brain region and can therefore be determined by local processes. These descriptions are of relevance to imaging studies that intend to establish correspondences between gross morphology and functional parameters such as behavior and brain activation.

Adult↗

Hemispheric lateralization of functions related to emotion.

We have reviewed the evidence that processes and functions related to perception and expression of emotions are represented asymmetrically in the cerebral hemispheres. The literature describes three possible aspects of emotional lateralization: that emotions are better recognized by the right hemisphere; that control of emotional expression and related behaviors takes place principally in the right hemisphere; and that the right hemisphere is specialized for dealing with negative emotions, while the left is specialized for dealing with positive emotions. Evidence for the three hypotheses derives from methodologically diverse studies in unimpaired, brain-lesioned, and mood-disordered populations. Relatively little of the work has been precisely replicated, and conclusions rest on parallel lines of evidence from diverse sources. The present level of knowledge suggests a model of emotional control based on interactive inhibition between a right negatively biased and left positively biased hemisphere. However, the details of such a model, including the precise conditions under which emotion-related functions are lateralized, and the mechanisms of such lateralization have yet to be elucidated.

Brain↗

Accessory nerve function in lateral selective neck dissection with undissected level IIb.

BACKGROUND: To investigate the accessory nerve function in lateral selective neck dissections (LSND) performed in laryngeal squamous cell carcinoma patients without dissection of level IIB. METHODS: Fifteen LSND were performed in 11 N0 laryngeal carcinoma patients with preservation of level IIB. Distal latencies, compound muscle action potentials (CMAP), and electromyography findings were investigated before surgery, during the 3rd postoperative week, and 3 months thereafter to compare the effects of the procedure on the accessory nerve. RESULTS: Distal latencies and CMAP values were significantly lower in the early and late postoperative periods when compared with preoperative values. In 8 patients, there was no motor unit potential (MUP) in the early postoperative period. However, in the late postoperative period, there was no MUP loss. CONCLUSIONS: Only temporary functional deterioration of the accessory nerve was seen in patients in whom LSND was performed with undissected level IIB.

Accessory Nerve↗