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PubMed2003

Predicting performance from functional imaging data: methods matter.

In the standard approach to functional imaging studies, brain-behavior relationships are studied by contrasting data obtained during different behavioral states. It is generally assumed that relative change yields meaningful data about relevant brain processes, and that the magnitude of the change reflects the extent of a region's involvement in the behavior being studied. The present study takes a different approach by asking the question, Can functional imaging data predict performance? Regional cerebral blood flow was measured using positron emission tomography in a group of 13 right-handed, normal volunteers during speech production and quiet baseline. A number of methodological assumptions were addressed by examining the relationships between different imaging measures derived from the same raw data and performance on the speech task. The results demonstrate that several common assumptions are not necessarily true. First, although measures based on "activated" scans alone had predictive value with respect to speech rate, measures based on contrasts between "baseline" and "activated" states did not. This was true regardless of whether the contrast was based on subtraction or covariance analyses. Second, while many regions demonstrated large signal increases during speech, speech rate could be predicted by a linear combination of data from two regions, neither of which had the highest "activation" peak, and one of which had a negative relationship with performance. The results demonstrate that contrasting experimental conditions do not necessarily isolate or enhance brain activity related to performance, and that the current assumptions about activation in functional imaging need to be reconsidered.

Adult↗

PubMed1997

The continuous performance test, identical pairs version (CPT-IP): III. Brain functioning during performance of numbers and shapes subtasks.

The numbers and shapes subtasks of the CPT-IP are difficulty-matched measures of independent aspects of attentional skill that have been used to differentiate the impairments of schizophrenics and major depressives. Previous studies suggest that they tap into lateralized aspects of attentional performance. To investigate this hypothesis, seven subjects free of psychiatric illness were presented with these CPT-IP subtasks during a SPECT procedure. Subtasks--4-digit number strings and nonsense shapes--were administered on successive weeks, in counterbalanced order, simultaneous with administration of 10 mCi 99mTc HMPAO. Scanning took place after 10 min of test performance. Quantitative data were extracted from each scan via a semi-automated region of interest (ROI) analysis which defined eight cortical and four subcortical ROI on each of five transverse slices. Data for each ROI were normalized and compared between task conditions. Results indicate that the two tasks produce different patterns of functioning within two general areas of the brain. First, during Numbers task performance, left-sided activity was increased on multiple transverse slices in an anterior subcortical region that incorporated the anterior cingulate, frontal white matter, and much of the basal ganglia. Left-sided activity was also increased in a posterior subcortical region including the left side of the thalamus. Lateralization of function, defined as relative activity on the left and right sides, changed within these regions across tasks, but primarily as a result of the contribution of increased or decreased activity on the left side alone. Second, relative perfusion to occipital regions, bilaterally, was more extensive during the Shapes task. These results suggest that subtle alterations in stimulus parameters can affect activation patterns in regions that are critically associated with task performance. They also suggest that the Numbers task may provide more robust activation of anterior attention systems, that may better discriminate the functioning of these systems in normal and psychopathological groups.

Adult↗

PubMed2005

Effects of muscle strength training and testosterone in frail elderly males.

PURPOSE: Determine the independent and combined effects of progressive resistance muscle strength training (PRMST) and testosterone on strength, muscle mass, and function in hypogonadal elderly male recuperative care patients. METHODS: Between 1999 and 2004, 71 subjects (mean age 78.2 +/- 6.4 yr, 86% white) were enrolled. After baseline one-repetition maximum (1RM) strength testing and then randomization to one of four treatment groups (low-resistance (20% of the 1RM) exercises and weekly injections of either 100 mg of testosterone enanthate or placebo or high-intensity PRMST (> or =80% 1RM) and weekly injections), each subject received training and injections for 12 wk. RESULTS: Ten subjects withdrew from the study before its completion. Based on intent-to-treat analyses, strength improved in all groups, but was greater with high-intensity PRMST compared with low-resistance exercise (e.g., leg press, (mean +/- SE), 28 +/- 4 vs 13 +/- 4%, P = 0.009). Although testosterone led to significantly greater increases in midthigh cross-sectional muscle area compared with placebo (7.9 +/- 1.3 vs 2.4 +/- 1.4%, P = 0.005), it produced only a nonsignificant trend toward greater strength gains (e.g., leg press 25 +/- 4 vs 16 +/- 4%, P = 0.144). Change in aggregate functional performance score (the sum of 4 functional performance test scores) did not differ between the four intervention groups nor with high-intensity PRMST compared with low-resistance exercise (7 +/- 5 vs 15 +/- 5%, P = 0.263). There was not a significant interaction between exercise and testosterone for any outcome. CONCLUSION: High-intensity PRMST is as safe and well tolerated as a similarly structured low-resistance exercise regimen for very frail elderly patients, but produces greater muscle strength improvements. The addition of testosterone leads to greater muscle size and a trend toward greater strength but did not produce a synergistic interaction with exercise. Neither intervention had a significant effect on functional performance.

Aged↗

PubMed2002

Validity of the Wechsler abbreviated scale of intelligence and other very short forms of estimating intellectual functioning.

Performance on the Wechsler Adult Intelligence Scale-III (WAIS-III) was compared to performance on the Wechsler Abbreviated Scale of Intelligence (WASI), as well as short form estimations of intellectual functioning derived from WAIS-III performance, in a mixed clinical sample of 72 participants. The WASI verbal IQ (VIQ) score was significantly higher than the WAIS-III VIQ, whereas performance IQ (PIQ) estimates all differed from actual WAIS-III PIQ and full scale IQ (FSIQ). Correlations of WAIS-III scores with WASI scores were consistently lower than were correlations between the WASI-III and all other short forms. Although maintaining administration times of 15 minutesfor a two-subtest FSIQ and 30 minutes for a four-subtest FSIQ, the WASI did not consistently demonstrate desirable accuracy in predicting scores obtained from the WAIS-III. The results suggest that clinicians should use the WASI cautiously if at all, especially when accurate estimates of individuals' WAIS-III results are needed.

Analysis of Variance↗

PubMed2003

Relation between brain activation and lexical performance.

Functional magnetic resonance imaging (fMRI) was used to determine whether performance on lexical tasks was correlated with cerebral activation patterns. We found that such relationships did exist and that their anatomical distribution reflected the neurocognitive processing routes required by the task. Better performance on intramodal tasks (determining if visual words were spelled the same or if auditory words rhymed) was correlated with more activation in unimodal regions corresponding to the modality of sensory input, namely the fusiform gyrus (BA 37) for written words and the superior temporal gyrus (BA 22) for spoken words. Better performance in tasks requiring cross-modal conversions (determining if auditory words were spelled the same or if visual words rhymed), on the other hand, was correlated with more activation in posterior heteromodal regions, including the supramarginal gyrus (BA 40) and the angular gyrus (BA 39). Better performance in these cross-modal tasks was also correlated with greater activation in unimodal regions corresponding to the target modality of the conversion process (i.e., fusiform gyrus for auditory spelling and superior temporal gyrus for visual rhyming). In contrast, performance on the auditory spelling task was inversely correlated with activation in the superior temporal gyrus possibly reflecting a greater emphasis on the properties of the perceptual input rather than on the relevant transmodal conversions.

Acoustic Stimulation↗

PubMed2005

Conflict's consequences: effects of social motives on postnegotiation creative and convergent group functioning and performance.

Two studies tested the effects of social motives during negotiation on postnegotiation group performance. In both experiments, a prosocial or a proself motivation was induced, and participants negotiated in 3-person groups about a joint market. In Experiment 1, groups subsequently performed an advertisement task. Consistent with the authors' predictions, results showed that proself groups performed worse on the convergent aspects of this task but better on the divergent aspects than prosocial groups. In Experiment 2, the authors manipulated social motive and negotiation (negotiation vs. no negotiation), and groups performed a creativity task (requiring divergent performance) or a planning task (requiring convergent performance). Proself groups showed greater dedication, functioned more effectively, and performed better than prosocial groups on the creativity task, whereas prosocial groups showed greater dedication, functioned more effectively, and performed better than proself groups on the planning task, and these effects only occurred when the task was preceded by group negotiation.

Adult↗

PubMed2000

Longitudinal quantitative measures of the natural course of low back pain recovery.

STUDY DESIGN: A prospective study was developed to quantify acute low back pain recovery. OBJECTIVE: To compare traditional self-report measures of low back pain recovery with a quantitative measure of recovery. SUMMARY OF BACKGROUND DATA: The magnitude of low back disorders in society continues to be a problem. To prevent secondary injuries, an understanding of recovery must be gained by comparing the natural course of recovery using several outcome measures. METHODS: For this study, 16 occupational and 16 nonoccupational patients with low back pain were recruited. Recovery was monitored prospectively every 2 weeks for 3 to 6 months, using subjective work status, pain symptoms, activities of daily living, and objective functional performance probability (trunk kinematics). RESULTS: Return to work underestimated the percentage of subjects impaired, as compared with all other outcome measures. Symptoms, activities of daily living, and functional performance probability all showed similar patterns of recovery for 0 to 12 weeks. At 14 weeks, there was a lag in functional performance recovery. Both symptoms and activities of daily living indicated that 80% of the population was recovered, whereas functional performance indicated the figure to be 68%. CONCLUSION: This prospective study demonstrates the natural course of recovery using several outcome measures. The objective kinematic functional performance measure of recovery quantifies a different aspect of impairment not evaluated by traditional subjective measures. Use of several outcome measures may lead to a better understanding of low back pain recovery or residual impairment, which may minimize the risk of recurrent injury.

Activities of Daily Living↗

PubMed1996

Fine motor outcomes in preschool children who receive occupational therapy services.

OBJECTIVE: This study examined preschool children's acquisition of fine motor skills and functional performance when occupational therapy services are included as part of the educational program. It also investigated the relationships among fine motor skills and functional performance in self-care, mobility, and social function. METHOD: Twenty-six preschool children who received weekly occupational therapy were studied. Measurements of their in-hand manipulation, tool use, eye-hand coordination, grasping strength, and functional performance in self-care, mobility, and social function were taken at the beginning and end of the school year. RESULTS: Raw and scaled scores showed significant improvements in all skill areas; standard scores showed slight improvement in eye-hand coordination and mobility function. Correlations of the motor skill tests with the functional performance scales using year-end data revealed significant correlations for in-hand manipulation, eye-hand coordination, and grasping strength with self-care function and mobility. CONCLUSIONS: The results demonstrate the level of change that occurs in fine motor skill and self-care, mobility, and social function during the course of the school year for preschoolers with moderate fine motor delays. The relationships found in the year-end testing imply that performance in underlying fine motor skills as the focus of occupational therapy intervention is associated with self-care and mobility function.

Achievement↗

PubMed1979

Performance intensity functions in cochlear and eighth nerve disorders.

In this report, performance intensity functions for monosyllabic materials (PI-PB) were obtained on two groups of subject: 20 patients with eighth nerve pathology and 15 individuals with Meniere's disease. The subjects with retrocochlear involvement exhibited marked deterioration in word recognition as the speech intensity was increased beyond the level required for a maximum discrimination score. Such a dramatic breakdown, referred to as the "rollover effect," was not seen to occur among the subjects with cochlear disorders. Hence, the PI-PB function appears to be a valuable tool for use in the special test battery.

Adolescent↗

PubMed1996

Impulsivity as a confounding factor in certain animal tests of cognitive function.

Performance in cognitive tasks which require the subject to wait and/or to process a large amount of information can be disrupted by an increase in impulsive-like behaviour. Accordingly, a decrease in impulsive-like behaviour can improve performance in such tasks. Conversely, impulsive-like behaviour may improve performance in cognitive tasks where simple and fast responses and/or only little information processing is required. Thus, impulsivity constitutes a confounding factor in studies of cognitive function. Impulsive-like behaviour may be modified by serotonergic (5-HT) activity, with underactivity in 5-HT neurotransmission increasing impulsivity and vice versa. Drug- or lesion-induced alteration in 5-HT neurotransmission may, therefore, constitute suitable tools to investigate the role of impulsivity in animal tests of cognitive function. Benzodiazepines also increase impulsive-like behaviour, possibly by decreasing 5-HT neurotransmission. Hence, the effects of modulation of 5-HT systems and of the benzodiazepine-binding site on performance in animals tests of cognitive function will be discussed. It is predicted that the effects of manipulations of serotonergic activity or of benzodiazepine administration depend upon the nature of the response required, and that these effects may be mediated through changes in impulse control.

Animals↗

PubMed2001

Exercise and training to optimize functional motor performance in stroke: driving neural reorganization?

Neurorehabilitation is increasingly taking account of scientific findings. Research areas directing stroke rehabilitation are neurophysiology; adaptability to use and activity; biomechanics; skill learning; and exercise science (task, context specificity). Understanding impairments and adaptations enables a reappraisal of interventions-for example, changes in motor control resulting from impairments (decreased descending inputs, reduced motor unit synchronization), secondary soft tissue changes (muscle length and stiffness changes) are adaptations to lesion and disuse. Changes in interventions include increasing emphasis on active exercise and task-specific training, active and passive methods of preserving muscle extensibility. Training has the potential to drive brain reorganization and to optimize functional performance. Research drives the development of training programs, and therapists are relying less on one-to-one, hands-on service delivery, making use of circuit training and group exercise and of technological advances (interactive computerized systems, treadmills) which increase time spent in active practice. Emphasis is on skill training, stressing cognitive engagement and practice, aiming to increase strength, control, skill, endurance, fitness, and social readjustment. Rehabilitation services remain slow to make the changes necessary to upgrade environments, attitudes, and rehabilitation methodologies to those shown to be more scientifically rational and for which there is evidence of effectiveness.

Exercise Therapy↗

PubMed1982

Patterns in the performance-intensity functions for phonetically balanced word lists and synthetic sentences in aged listeners.

The performance intensity-phonetically balanced (PI-PB) and performance intensity-synthetic sentence identification (PI-SSI) functions were determined for 62 elderly patients (100 ears) with presbyacusis. A comparison of these functions was performed to determine whether patients older than 60 years exhibited peripheral or central PI-PB/PI-SSI patterning. Fifty-eight ears of the 100 ears examined showed central patterning. Furthermore, two diagnostically important central patterns were identified. The implications of the current data as well as the clinical application of PI-PB/PI-SSI testing for the evaluation of peripheral and central auditory effects in aged listeners are described.

Aged↗

PubMed2005

Female hip fracture patients had poorer performance-based functioning than community-dwelling peers over 2-year follow-up period.

BACKGROUND AND OBJECTIVES: Compare performance-based functioning over 2 years among elderly women hip fracture patients vs. community-dwelling older women. METHODS AND SETTING: 268 hip fracture patients from eight hospitals in Baltimore, MD, in 1990-1991, and 486 respondents from the Women's Health and Aging Study I (WHAS I) were assessed prospectively at 6-month intervals for 2 years. Usual and rapid walking speeds, and chair rise time, were calculated and standardized to the baseline distribution of the WHAS subsample. RESULTS: At baseline, all respondents were aged 65+ years, White, cognitively intact, and could walk across a room independently. Hip fracture patients had significantly poorer functioning than WHAS respondents at each follow-up interview through 24 months postfracture. The difference was greatest at 6 months: mean walking speed for hip fracture patients was approximately one standard deviation lower than for WHAS respondents for usual pace (adjusted difference = -1.06, 95% confidence interval (CI) = -1.22, -0.89) and rapid pace (adjusted difference = -0.95, 95% CI = -1.13, -0.79). These differences were most pronounced among respondents who were aged 80+ years or had comorbid conditions. CONCLUSION: Elderly women had poorer performance-based functioning over 2 years following hip fracture than would be expected by normal aging in same-aged women.

Activities of Daily Living↗

PubMed2000

Self-reported walking ability predicts functional mobility performance in frail older adults.

OBJECTIVE: To determine how self-reported physical function relates to performance in each of three mobility domains: walking, stance maintenance, and rising from chairs. DESIGN: Cross-sectional analysis of older adults. SETTING: University-based laboratory and community-based congregate housing facilities. PARTICIPANTS: Two hundred twenty-one older adults (mean age, 79.9 years; range, 60-102 years) without clinical evidence of dementia (mean Folstein Mini-Mental State score, 28; range, 24-30). INTERVENTION AND MAIN OUTCOME MEASURES: We compared the responses of these older adults on a questionnaire battery used by the Established Populations for the Epidemiologic Study of the Elderly (EPESE) project, to performance on mobility tasks of graded difficulty. Responses to the EPESE battery included: (1) whether assistance was required to perform seven Katz activities of daily living (ADL) items, specifically with walking and transferring; (2) three Rosow-Breslau items, including the ability to walk up stairs and walk a half mile; and (3) five Nagi items, including difficulty stooping, reaching, and lifting objects. The performance measures included the ability to perform, and time taken to perform, tasks in three summary score domains: (1) walking ("Walking," seven tasks, including walking with an assistive device, turning, stair climbing, tandem walking); (2) stance maintenance ("Stance," six tasks, including unipedal, bipedal, tandem, and maximum lean); and (3) chair rise ("Chair Rise," six tasks, including rising from a variety of seat heights with and without the use of hands for assistance). A total score combines scores in each Walking, Stance, and Chair Rise domain. We also analyzed how cognitive/ behavioral factors such as depression and self-efficacy related to the residuals from the self-report and performance-based ANOVA models. RESULTS: Rosow-Breslau items have the strongest relationship with the three performance domains, Walking, Stance, and Chair Rise (eta-squared ranging from 0.21 to 0.44). These three performance domains are as strongly related to one Katz ADL item, walking (eta-squared ranging from 0.15 to 0.33) as all of the Katz ADL items combined (eta-squared ranging from 0.21 to 0.35). Tests of problem solving and psychomotor speed, the Trails A and Trails B tests, are significantly correlated with the residuals from the self-report and performance-based ANOVA models. CONCLUSIONS: Compared with the rest of the EPESE self-report items, self-report items related to walking (such as Katz walking and Rosow-Breslau items) are better predictors of functional mobility performance on tasks involving walking, stance maintenance, and rising from chairs. Compared with other self-report items, self-reported walking ability may be the best predictor of overall functional mobility.

Activities of Daily Living↗

PubMedDate not supplied

Sensory and cognitive factors influencing functional ability in older adults.

BACKGROUND: Age-related sensory and cognitive impairments have been related to functional performance in older adults. With regard to cognitive abilities, processing speed in particular may be strongly related to older adults' abilities to perform everyday tasks. Identifying and comparing cognitive correlates of functional performance is particularly important in order to design interventions to promote independence and prevent functional disability. OBJECTIVE: The present study examined the relative importance of cognitive (specifically, speeded and nonspeeded) and sensory factors in relation to older adults' functional abilities. Functional abilities included measures of mobility and performance of everyday activities. METHODS: A cross-sectional study design was employed. Five hundred and thirty adults between the ages of 62 and 94 completed measures of sensory, cognitive (including processing speed, attention, memory, intelligence) and functional abilities. RESULTS: Overall, functional performance was most strongly associated with cognitive speed performance, but nonspeeded cognitive and sensory abilities also accounted for significant amounts of variance in functional performance. Age explained a small but statistically significant amount of additional variance in some functional abilities, but no additional variance in self-reported mobility measures. CONCLUSION: These findings point to the potential impact of multifaceted training programs, targeting both sensory and cognitive abilities for maintaining functional abilities.

Activities of Daily Living↗

PubMed2006

The effect of Ginkgo biloba on functional measures in multiple sclerosis: a pilot randomized controlled trial.

BACKGROUND: Multiple sclerosis (MS) is a chronic demyelinating neurological disease afflicting young and middle-aged adults, resulting in problems with coordination, strength, cognition, affect, and sensation. OBJECTIVE: The objective of this study was to determine whether a ginkgo extract (EGb 761) improved functional performance in individuals with MS. DESIGN: This study used a double-blind, placebo-controlled, parallel group design. The end point was change between baseline (ie, preintervention) and follow-up evaluation following a regimen of four tablets per day at 60 mg per tablet for four weeks. SETTING: The study was conducted in academic and clinical-based settings. PATIENTS/PARTICIPANTS: Twenty-two individuals with MS were randomly assigned to either the treatment or control condition. Groups did not differ with respect to age, IQ, and education. INTERVENTION: Half of the subjects received 240 mg per day of ginkgo special extract (EGb 761), and the other half received placebo. MAIN OUTCOME MEASURE: The main outcome measures assessed depression (Center for Epidemiologic Studies of Depression Scale [CES-D]), anxiety (State-Trait Anxiety Inventory [STAI]), fatigue (Modified Fatigue Impact Scale [MFIS]); symptom severity (Symptom Inventory [SI]) and functional performance (Functional Assessment of Multiple Sclerosis [FAMS]). RESULTS: The ginkgo group had significantly more individuals showing improvement on four or more measures with improvements associated with significantly larger effect sizes on measures of fatigue, symptom severity, and functionality. The ginkgo group also exhibited less fatigue at follow-up compared with the placebo group. CONCLUSIONS: This exploratory pilot study showed that no adverse events or side effects were reported and that ginkgo exerted modest beneficial effects on select functional measures (eg, fatigue) among some individuals with MS.

Activities of Daily Living↗

PubMed2005

A multicenter study of two magnetic resonance spectroscopy techniques in individuals with HIV dementia.

PURPOSE: To evaluate single-voxel proton magnetic resonance spectroscopy (SV-MRS) and magnetic resonance spectroscopic imaging (MRSI) metabolite results in individuals with HIV dementia. MATERIALS AND METHODS: Twenty HIV-positive (HIV+) individuals underwent SV-MRS (TE 35 msec) and MRSI (TE 280 msec). Results were stratified according to serostatus, dementia severity, psychomotor speed performance, and functional impairment. RESULTS: HIV+ individuals with psychomotor slowing had an increased myoinositol/creatine (mI/Cr) ratio (0.63 vs. 0.45) in the frontal white matter using SV-MRS and an increased choline (Cho)/Cr ratio (1.88 vs. 1.41) in the mesial frontal gray matter using MRSI compared to HIV+ individuals without psychomotor slowing. Using MRSI, subjects with HIV dementia also had a decreased N-acetyl aspartate (NAA)/Cho ratio (1.55 vs. 2.53) compared to HIV+ individuals without cognitive impairment in the mesial frontal gray matter. Both techniques detected metabolite ratio abnormalities associated with abnormal functional performance. CONCLUSION: SV-MRS and MRSI offer complementary roles in evaluating individuals with HIV dementia. Short TE SV-MRS measures mI, which may be elevated in early HIV dementia, whereas MRSI provides wider spatial coverage to examine specific regional changes.

AIDS Dementia Complex↗

PubMed2003

Somatomotor functional MRI in a large congenital arachnoid cyst.

The immature human brain, when damaged, is able to reorganise functionally. We performed functional MRI during eight different movements in a patient found incidentally to have an extensive, frontal, congenital arachnoid cyst, looking at which neural substrates contribute to motor control. Significant changes from the normal pattern of activation were seen in cortical and cerebellar areas which could not be accounted for by the space-occupying effect of the cyst alone. These findings in this asymptomatic patient with a congenital anomaly demonstrate an alternative organisation of the central motor system, with a preservation of neurological function.

Adult↗