Influence of age and gender in motor performance in healthy subjects

Lower motor performance is linked with poor sleep quality, depressive symptoms, and grey matter volume alterations

Motor performance (MP) is essential for functional independence and well-being, particularly in later life. However, the relationship between behavioural aspects such as sleep quality and depressive symptoms, which contribute to MP, and the underlying structural brain substrates of their interplay remains unclear. This study used three population-based cohorts of younger and older adults (n=1,950) from the Human Connectome Project-Young Adult (HCP-YA), HCP-Aging (HCP-A), and enhanced Nathan Kline Institute-Rockland sample (eNKI-RS). Several canonical correlation analyses were computed within a machine learning framework to assess the associations between each of the three domains (sleep quality, depressive symptoms, grey matter volume (GMV)) and MP. The HCP-YA analyses showed progressively stronger associations between MP and each domain: depressive symptoms (unexpectedly positive, r=0.13, SD=0.06), sleep quality (r=0.17, SD=0.05), and GMV (r=0.19, SD=0.06). Combining sleep and depressive symptoms significantly improved the canonical correlations (r=0.25, SD=0.05), while the addition of GMV exhibited no further increase (r=0.23, SD=0.06). In young adults, better sleep quality, mild depressive symptoms, and GMV of several brain regions were associated with better MP. This was conceptually replicated in young adults from the eNKI-RS cohort. In HCP-Aging, better sleep quality, fewer depressive symptoms, and increased GMV were associated with MP. Robust multivariate associations were observed between sleep quality, depressive symptoms and GMV with MP, as well as age-related variations in these factors. Future studies should further explore these associations and consider interventions targeting sleep and mental health to test the potential effects on MP across the lifespan.

Reliability and Construct Validity of a Mobile Application for the Finger Tapping Test Evaluation in People with Multiple Sclerosis

The finger tapping test (FTT) is a tool to evaluate the motor performance of the hand and fingers and eye-hand coordination with applicability in people with multiple sclerosis (pwMS). The aim of this study was to evaluate the intra- and inter-rater reliability of the TappingPro® mobile app and the construct validity between this app and validated clinical scales for motor performance in healthy subjects and pwMS. 42 healthy subjects (mean age 25.05) and 13 pwMS (mean age 51.69, EDSS between 3 and 7.5E) participated. FTT was performed with the TappingPro® mobile app. All participants were examined twice, with a one-week interval between the two appointments. For the analysis of construct validity, the Jamar® hydraulic hand dynamometer, Box and Blocks Test (BBT), and Nine Hole Peg Test (NHPT) were used. The intra-rater reliability showed a good correlation (Intraclass Correlation Coefficient, ICC > 0.787) for both upper limbs and both times of FTT for healthy subjects, and an excellent correlation (ICC > 0.956) for upper limbs and both times of FTT for pwMS. The ICC for the inter-rater reliability was good (ICC = 0.869) for the non-dominant upper limb in the FTT 10 s of the healthy subjects, and excellent (ICC > 0.904) for all the other measurements of the healthy subjects and pwMS. However, the Bland-Altman plots showed disagreement between observers and measurements that should be considered in the interpretation of clinical evaluations. The correlation analysis for healthy subjects showed poor associations between all variables, except for the association between hand grip strength and the FTT 60 s in the non-dominant upper limb, which had a moderate coefficient. For pwMS, there were moderate to excellent associations between BBT and the NHPT and FTT for both upper limbs. The correlations between hand grip strength and FFT were poor. This mobile app could be a useful and low-cost assessment tool in pwMS, allowing a simple evaluation and follow-up that has excellent correlation with clinical scales validated in this pathology.

Motor performance and functional connectivity between the posterior cingulate cortex and supplementary motor cortex in bipolar and unipolar depression

Although implicated in unsuccessful treatment, psychomotor deficits and their neurobiological underpinnings in bipolar (BD) and unipolar (UD) depression remain poorly investigated. Here, we hypothesized that motor performance deficits in depressed patients would relate to basal functional coupling of the hand primary motor cortex (M1) and the posterior cingulate cortex (PCC) with the supplementary motor area (SMA). We performed a longitudinal, naturalistic study in BD, UD and matched healthy controls comprising of two resting-state functional MRI measurements five weeks apart and accompanying assessments of motor performance using a finger tapping task (FTT). A subject-specific seed-based analysis describing functional connectivity between PCC-SMA as well as M1-SMA was conducted. The basal relationships with motor performance were investigated using linear regression models and all measures were compared across groups. Performance in FTT was impaired in BD in comparison to HC in both sessions. Behavioral performance across groups correlated significantly with resting state functional coupling of PCC-SMA, but not of M1-SMA regions. This relationship was partially reflected in a reduced PCC-SMA connectivity in BD vs HC in the second session. Exploratory evaluation of large-scale networks coupling (SMN-DMN) exhibited no correlation to motor performance. Our results shed new light on the association between the degree of disruption in the SMA-PCC anticorrelation and the level of motor impairment in BD.

Concurrent training associated with moderate walnut consumption improved isokinetic strength, subjective sleep quality, cognitive performance and postural balance in elderly active men: a randomized controlled trial

AIMS

To investigate the effects of concurrent training (resistance and endurance) associated with moderate walnut consumption on isokinetic strength, subjective sleep quality, cognitive performance and postural balance in physically active elderly men.

METHODS

Twenty healthy elderly men were divided into two matched groups, in a randomized controlled experiment. They have participated in three training sessions per week: concurrent (strength and endurance) training + ad libitum diet with walnuts (15 g/day for 6 weeks, CTW: n = 10) and concurrent training + ad libitum diet (CT: n = 10). Isokinetic strength, Spiegel questionnaire, Montreal cognitive assessment and postural balance parameters were assessed 48 h pre- and post-intervention.

RESULTS

Absolute peak torque of knee extensors and knee flexors significantly increased compared to pre-training in CTW (15.2% ± 6.7; 13.2% ± 2.3, p < 0.05, respectively) and CT (10.6% ± 6.8; 7.4% ± 2.9, p < 0.05, respectively). Subjective sleep quality increased compared to pre-training for CTW and CT (24% ± 14.4; 10.5% ± 9.4, p < 0.05, respectively) with a significantly greater increase in CTW (p < 0.05). Cognitive performance measured by Montreal cognitive assessment (MoCA) increased only in CTW compared to baseline (7.7% ± 2.5, p < 0.05). Postural balance parameters with dual task decreased only in CTW compared to baseline.

CONCLUSIONS

The present study clearly revealed that concurrent training alone or associated with daily walnut (15 g) consumption for 6 weeks significantly increased knee isokinetic strength, support leg standing parameters and sleep quality. Meanwhile, cognitive performance evaluated by MoCA test and postural balance with dual task were improved for CTW group only.

A Case Study of the Validity of Web-based Visuomotor Rotation Experiments

Web-based experiments are gaining momentum in motor learning research because of the desire to increase statistical power, decrease overhead for human participant experiments, and utilize a more demographically inclusive sample population. However, there is a vital need to understand the general feasibility and considerations necessary to shift tightly controlled human participant experiments to an online setting. We developed and deployed an online experimental platform modeled after established in-laboratory visuomotor rotation experiments to serve as a case study examining remotely collected data quality for an 80-min experiment. Current online motor learning experiments have thus far not exceeded 60 min, and current online crowdsourced studies have a median duration of approximately 10 min. Thus, the impact of a longer-duration, web-based experiment is unknown. We used our online platform to evaluate perturbation-driven motor adaptation behavior under three rotation sizes (±10°, ±35°, and ±65°) and two sensory uncertainty conditions. We hypothesized that our results would follow predictions by the relevance estimation hypothesis. Remote execution allowed us to double (n = 49) the typical participant population size from similar studies. Subsequently, we performed an in-depth examination of data quality by analyzing single-trial data quality, participant variability, and potential temporal effects across trials. Results replicated in-laboratory findings and provided insight on the effect of induced sensory uncertainty on the relevance estimation hypothesis. Our experiment also highlighted several specific challenges associated with online data collection including potentially smaller effect sizes, higher data variability, and lower recommended experiment duration thresholds. Overall, online paradigms present both opportunities and challenges for future motor learning research.

Sex-related differences in upper limb motor function in healthy subjects and multiple sclerosis patients: a multiparametric MRI study

BACKGROUND

We investigated sex-related differences in upper limb motor performance tested with the 9-Hole Peg Test (9HPT) in healthy controls (HC) and multiple sclerosis (MS) patients and their MRI substrates.

MATERIALS AND METHODS

We enrolled 94 HC and 133 MS patients, who underwent neurological examination, 9HPT and brain 3T MRI, with sequences for regional grey matter volume (GMV), white matter (WM) fractional anisotropy (FA) and resting state (RS) functional connectivity (FC) analysis. Associations between MRI variables and 9HPT performance were analyzed with general linear models.

RESULTS

9HPT performance was better in HC vs MS patients, and in female vs male HC. Regional GMV analysis showed: associations between better 9HPT performance and higher GMV in motor and cognitive cortical areas in HC, with stronger positive correlations in females vs males. In MS, worse 9HPT performance correlated with lower volume in motor and cognitive areas. Sex-related differences were minimal and mostly found in cerebellar areas. WM FA analysis disclosed neither associations with 9HPT performance in HC, nor sex-related differences in MS. RS FC analysis showed: in the sensorimotor network, stronger associations of RS FC with 9HPT performance in female vs male HC and no sex-related differences in MS; in the cerebellar network, no sex-related differences in HC but stronger negative correlation in left cerebellum in male vs female MS patients.

CONCLUSIONS

Sex influences 9HPT performance in HC, mainly through differences in volume and RS FC of motor and cognitive areas. Sex-related effects on motor performance become secondary but still present in MS.

Neuropsychological Test Norms for the Assessment of HIV-Associated Neurocognitive Impairment Among South African Adults

Reliable and valid neurocognitive (NC) test batteries that assess multiple domains of cognitive functioning are vital tools in the early detection of HIV-associated NC impairment. The HIV Neurobehavioral Research Center's International Neurobehavioral Battery (HNRC Battery) is one such diagnostic tool and has shown cultural validity in several international neuroHIV studies. However, no published norms are currently available for the full HNRC Battery in South Africa. To accurately interpret NC test results, appropriate reference norms are required. In light of this challenge, data were collected from 500 healthy, HIV-uninfected participants to develop demographically corrected South African norms. When demographically corrected United States of America (U.S.) norms were applied to the performance scores of our neurologically intact, HIV-negative sample, an impairment rate of 62.2% was observed compared to a 15.0% impairment rate when the newly generated South African norms were applied. These results reiterate the findings of other low- and middle-income countries, highlighting the need for localized, country-specific norms when interpreting NC performance.

Difficulties in the use of medications by elderly people followed up in a cohort study in Southern Brazil

OBJECTIVE

This study aimed to assess the need for help by elderly people to take their medications, the difficulties related to this activity, the frequency of forgotten doses, and factors associated.

METHODS

Cross-sectional study conducted with a cohort of elderly people (60 years and over - "COMO VAI?" [How do you do?] study), where the need for help to properly take medication and the difficulties faced in using them were evaluated. The Poisson regression model was used to estimate the crude and adjusted prevalence ratios (PR) of the outcomes and respective 95% confidence intervals according to the characteristics of the sample.

RESULTS

In total, 1,161 elderly people were followed up. The prevalence of participants who reported requiring help with medication was 15.5% (95%CI 13.5-17.8), and the oldest subjects, with lower educational levels, in worse economic situations, on four or more medications and in bad self-rated health were the ones who needed help the most. Continuous use of medication was reported by 83.0% (95%CI 80.7-85.1) of the sample and most participants (74.9%; 95%CI 72.0-77.5) never forgot to take their medications.

CONCLUSION

The need for help to use medications was shown to be influenced by social and economic determinants. Studies assessing the difficulties in medication use by the elderly are important to support policies and practices to improve adherence to treatment and the rational use of medications.

Difficulties in the use of medications by elderly people followed up in a cohort study in Southern Brazil

Objective:

This study aimed to assess the need for help by elderly people to take their medications, the difficulties related to this activity, the frequency of forgotten doses, and factors associated.

Methods:

Cross-sectional study conducted with a cohort of elderly people (60 years and over — “COMO VAI?” [How do you do?] study), where the need for help to properly take medication and the difficulties faced in using them were evaluated. The Poisson regression model was used to estimate the crude and adjusted prevalence ratios (PR) of the outcomes and respective 95% confidence intervals according to the characteristics of the sample.

Results:

In total, 1,161 elderly people were followed up. The prevalence of participants who reported requiring help with medication was 15.5% (95%CI 13.5–17.8), and the oldest subjects, with lower educational levels, in worse economic situations, on four or more medications and in bad self-rated health were the ones who needed help the most. Continuous use of medication was reported by 83.0% (95%CI 80.7–85.1) of the sample and most participants (74.9%; 95%CI 72.0–77.5) never forgot to take their medications.

Conclusion:

The need for help to use medications was shown to be influenced by social and economic determinants. Studies assessing the difficulties in medication use by the elderly are important to support policies and practices to improve adherence to treatment and the rational use of medications.

Novel 3-D action video game mechanics reveal differentiable cognitive constructs in young players, but not in old

Video game research predominantly uses a “one game-one function” approach—researchers deploy a constellation of task-like minigames to span multiple domains or consider a complex video game to essentially represent one cognitive construct. To profile cognitive functioning in a more ecologically valid setting, we developed a novel 3-D action shooter video game explicitly designed to engage multiple cognitive domains. We compared gameplay data with results from a web-based cognitive battery (WebCNP) for 158 participants (aged 18–74). There were significant negative main effects on game performance from age and gender, even when controlling for prior video game exposure. Among younger players, game mechanics displayed significant and unique correlations to cognitive constructs such as aim accuracy with attention and stealth with abstract thinking within the same session. Among older players the relation between game components and cognitive domains was unclear. Findings suggest that while game mechanics within a single game can be deconstructed to correspond to existing cognitive metrics, how game mechanics are understood and utilized likely differs between the young and old. We argue that while complex games can be utilized to measure distinct cognitive functions, the translation scheme of gameplay to cognitive function should not be one-size-fits-all across all demographics.

Age-related decline in cortical inhibitory tone strengthens motor memory

Ageing disrupts the finely tuned excitation/inhibition balance (E:I) across cortex via a natural decline in inhibitory tone (γ-amino butyric acid, GABA), causing functional decrements. However, in young adults, experimentally lowering GABA in sensorimotor cortex enhances a specific domain of sensorimotor function: adaptation memory. Here, we tested the hypothesis that as sensorimotor cortical GABA declines naturally with age, adaptation memory would increase, and the former would explain the latter. Results confirmed this prediction. To probe causality, we used brain stimulation to further lower sensorimotor cortical GABA during adaptation. Across individuals, how stimulation changed memory depended on sensorimotor cortical E:I. In those with low E:I, stimulation increased memory; in those with high E:I stimulation reduced memory. Thus, we identified a form of motor memory that is naturally strengthened by age, depends causally on sensorimotor cortex neurochemistry, and may be a potent target for motor skill preservation strategies in healthy ageing and neurorehabilitation.

Fractional Anisotropy in Selected, Motor-Related White Matter Tracts and Its Cross-Sectional and Longitudinal Associations With Motor Function in Healthy Older Adults

Background

While it is well-known that deficits in motor performance and brain structural connectivity occur in the course of healthy aging, it is still unclear if and how these changes are related to each other. While some cross-sectional studies suggest that white matter (WM) microstructure is positively associated with motor function in healthy older adults, more evidence is needed. Moreover, longitudinal data is required to estimate whether similar associations can be found between trajectories of change in WM microstructure and motor function. The current study addresses this gap by investigating age-associations and longitudinal changes in WM microstructure and motor function, and the cross-sectional (level-level) and longitudinal (level-change, change-change) association between these two domains.

Method

We used multiple-occasion data (covering 4 years) from a large sample (N = 231) of healthy older adults from the Longitudinal Healthy Aging Brain (LHAB) database. To measure WM microstructure, we used diffusion-weighted imaging data to compute mean FA in three selected WM tracts [forceps minor (FMIN); superior longitudinal fasciculus (SLF); corticospinal tract (CST)]. Motor function was measured via two motor speed tests (grooved pegboard, finger tapping) and one motor strength test (grip force test), separately for the left and the right hand. The statistical analysis was conducted with longitudinal growth curve models in the structural equation modeling framework.

Results

The results revealed longitudinal decline and negative cross-sectional age-associations for mean WM FA in the FMIN and SLF, and for motor function in all tests, with a higher vulnerability for left than right hand motor performance. Regarding cross-domain associations, we found a significant positive level-level correlation among mean WM FA in the FMIN with motor speed. Mean FA in SLF and CST was not correlated with motor performance measures, and none of the level-change or change-change associations were significant. Overall, our results (a) provide important insights into aging-related changes of fine motor abilities and FA in selected white matter tracts associated with motor control, (b) support previous cross-sectional work showing that neural control of movement in older adults also involves brain structures outside the core motor system and (c) align with the idea that, in healthy aging, compensatory mechanisms may be in place and longer time delays may be needed to reveal level-change or change-change associations.

Exploring Movement Impairments in Patients With Parkinson's Disease Using the Microsoft Kinect Sensor: A Feasibility Study

Background: Current assessments of motor symptoms in Parkinson's disease are often limited to clinical rating scales. Objectives: To develop a computer application using the Microsoft Kinect sensor to assess performance-related bradykinesia. Methods: The developed application (Motorgame) was tested in patients with Parkinson's disease and healthy controls. Participants were assessed with the Movement Disorder Society Unified Parkinson's disease Rating Scale (MDS-UPDRS) and standardized clinical side effect rating scales, i.e., UKU Side Effect Rating Scale and Simpson-Angus Scale. Additionally, tests of information processing (Symbol Coding Task) and motor speed (Token Motor Task), together with a questionnaire, were applied. Results: Thirty patients with Parkinson's disease and 33 healthy controls were assessed. In the patient group, there was a statistically significant (p < 0.05) association between prolonged time of motor performance in the Motorgame and upper body rigidity and bradykinesia (MDS-UPDRS) with the strongest effects in the right hand (p < 0.001). In the entire group, prolonged time of motor performance was significantly associated with higher Simson-Angus scale rigidity score and higher UKU hypokinesia scores (p < 0.05). A shortened time of motor performance was significantly associated with higher scores on information processing (p < 0.05). Time of motor performance was not significantly associated with Token Motor Task, duration of illness, or hours of daily physical activity. The Motorgame was well-accepted. Conclusions: In the present feasibility study the Motorgame was able to detect common motor symptoms in Parkinson's disease in a statistically significant and clinically meaningful way, making it applicable for further testing in larger samples.

Time allocation to active domains, physical activity, and health indicators in older adults: cross-sectional results from the OUTDOOR ACTIVE study

BACKGROUND

Physical activity (PA) is one of the key determinants of healthy ageing. Research showed that time allocation plays an important role in PA. Therefore, an understanding of the time use of older adults is crucial for developing PA programs. The aim of this study was to examine the associations of time allocation and objectively measured PA, and several health indicators in older adults.

METHODS

In this cross-sectional study all 915 participants of the OUTDOOR ACTIVE study were included. The participants were 65 to 75 years old and resided in a subdistrict of Bremen, Germany (50.9% female). The active domains were derived from the SLOTH model (leisure activities, occupation, active transport, home-based activities). PA was objectively measured with accelerometers over seven consecutive days. Binary logistic regressions were used to test the associations of total PA and time spent in the domains with several health indicators (self-rated health, overweight, obesity, activities of daily living (ADL)).

RESULTS

Participants over the age of 70 years were significantly less physically active than those under 70 years and women were significantly more physically active than men. Regardless of age and sex, most time was spent on home-based activities (women: 118.5 ± 87.8 min/day; men: 80.2 ± 69.4 min/day). Both PA and time spent on leisure activities were associated with a lower risk of bad self-rated health (0.36; 95%-CL: 0.20, 0.65 for PA; 0.93; 95%-CL: 0.87, 0.99 for leisure activities) and less limitations in ADL. PA and active transport seemed to lower the risk of overweight (0.39; 95%-CL: 0.25, 0.62 for PA; 0.80; 95%-CL: 0.69, 0.93 for active transport) and obesity (0.36; 95%-CL: 0.21, 0.60 for PA; 0.77; 95%-CL: 0.64, 0.92 for active transport). Having an occupation was associated with a lower risk of bad self-rated health (0.60; 95%-CL: 0.40, 0.92).

CONCLUSIONS

The results of this study provide insights in the time allocation to active domains and total PA of older adults, as well as the associations with health indicators. These findings have important implications for the development of PA programs and guidelines. Future research should examine the associations further in longitudinal studies.

Failure to Engage Neural Plasticity through Practice of a High-difficulty Task is Accompanied by Reduced Motor Skill Retention in Older Adults

While the difficulty of a motor task can act as a stimulus for learning in younger adults, it is unknown how task difficulty interacts with age-related reductions in motor performance and altered brain activation. We examined the effects of task difficulty on motor performance and used electroencephalography (EEG) to probe task-related brain activation after acquisition and 24-h retention of a mirror star-tracing skill in healthy older adults (N = 36, 65-86 years). The results showed that the difficulty of the motor skill affected both the magnitude of motor skill learning and the underlying neural mechanisms. Behavioral data revealed that practicing a motor task at a high difficulty level hindered motor skill consolidation. The EEG data indicated that task difficulty modulated changes in brain activation after practice. Specifically, a decrease in task-related alpha power in frontal and parietal electrodes was only present after practice of the skill at the low and medium, but not the high difficulty level. Taken together, our findings show that a failure to engage neural plasticity through practice of a high-difficulty task is accompanied by reduced motor skill retention in older adults. The data help us better understand how older adults learn new motor skills and might have implications for prescribing motor skill practice according to its difficulty in rehabilitation settings.

Temporal and Force Characteristics of Rapid Single-Finger Tapping in Healthy Older Adults

The purpose of this study was to examine finger motor function in terms of temporal and force characteristics during rapid single-finger tapping in older adults. Ten older and 10 young males performed maximum frequency tapping by the index, middle, ring, or little finger. Nontapping fingers were maintained in contact with designated keys during tasks. Key-contact force for each of the fingers was monitored using four force transducers. The older subjects had slower tapping rates of all fingers during single-finger tapping than the young subjects. The average forces exerted by the nontapping fingers were larger for the older subjects than for the young subjects during tapping with the ring and little fingers. The ranges of the nontapping finger forces were larger for the older subjects during tapping by the middle, ring, and little fingers than for the young subjects. Thus, the motor abilities of the fingers evaluated by rapid single-finger tapping decline in older adults compared with young adults in terms of both movement speed and finger independence.

Neuropsychology of aging

All people want to age "successfully," maintaining functional capacity and quality of life as they reach advanced age. Achieving this goal depends on preserving optimal cognitive and brain functioning. Yet, significant individual differences exist in this regard. Some older adults continue to retain most cognitive abilities throughout their lifetime. Others experience declines in cognitive and functional capacity that range from mild decrements in certain cognitive functions over time to severe dementia among those with neurodegenerative diseases. Even among relatively healthy "successful agers," certain cognitive functions are reduced from earlier levels. This is particularly true for cognitive functions that are dependent on cognitive processing speed and efficiency. Working memory and executive and attentional functions tend to be most vulnerable. Learning and memory functions are also usually reduced, although in the absence of neurodegenerative disease learning and retrieval efficiency rather than memory storage are affected. Other functions, such as visual perception, language, semantics, and knowledge, are often well preserved. Structural, functional, and physiologic/metabolic brain changes correspond with age-associated cognitive decline. Physiologic and metabolic mechanisms, such as oxidative stress and neuroinflammation, may contribute to these changes, along with the contribution of comorbidities that secondarily affect the brain of older adults. Cognitive frailty often corresponds with physical frailty, both affected by multiple exogenous and endogenous factors. Neuropsychologic assessment provides a way of measuring the cognitive and functional status of older adults, which is useful for monitoring changes that may be occurring. Neuroimaging is also useful for characterizing age-associated structural, functional, physiologic, and metabolic brain changes, including alterations in cerebral blood flow and metabolite concentrations. Some interventions that may enhance cognitive function, such as cognitive training, neuromodulation, and pharmacologic approaches, exist or are being developed. Yet, preventing, slowing, and reversing the adverse effects of cognitive aging remains a challenge.

Effects of Temporary Functional Deafferentation in Chronic Stroke Patients: Who Profits More?

Temporary functional deafferentation (TFD) by an anesthetic cream on the stroke-affected forearm was shown to improve sensorimotor abilities of stroke patients. The present study investigated different predictors for sensorimotor improvements during TFD and indicated outcome differences between patients grouped in subcortical lesions only and lesions with any cortical involvement. Thirty-four chronic stroke patients were temporarily deafferented on the more affected forearm by an anesthetic cream. Somatosensory performance was assessed using von Frey Hair and grating orientation task; motor performance was assessed by a shape-sorter-drum task. Seven potential predictors were entered into three linear multiple regression models. Furthermore, effects of TFD on outcome variables for the two groups (cortical versus subcortical lesion) were compared. Sex and sensory deficit were significant predictors for changes in motor function while age accounted for changes in grating orienting task. Males, patients with a stronger sensory deficit, and older patients profited more. None of the potential predictors made significant contributions to changes in threshold for touch. Furthermore, there were no differences in sensorimotor improvement between lesion site groups. The effects of TFD together with the low predictability of the investigated parameters suggest that characteristics of patients alone are not suitable to exclude some patients from TFD.

Missense Gamma-Aminobutyric Acid Receptor Polymorphisms Are Associated with Reaction Time, Motor Time, and Ethanol Effects in Vivo

Background: The Gamma-aminobutyric acid type A receptor (GABA-A receptor) is affected by ethanol concentrations equivalent to those reached during social drinking. At these concentrations, ethanol usually causes impairment in reaction and motor times in most, but not all, individuals.

Objectives: To study the effect of GABA-A receptor variability in motor and reaction times, and the effect of low ethanol doses.

Methods: Two hundred and fifty healthy subjects received one single dose of 0.5 g/Kg ethanol per os. Reaction and motor times were determined before ethanol challenge (basal), and when participants reached peak ethanol concentrations. We analyzed all common missense polymorphisms described in the 19 genes coding for the GABA-A receptor subunits by using TaqMan probes.

Results: The GABRA6 rs4454083 T/C polymorphisms were related to motor times, with individuals carrying the C/C genotype having faster motor times, both, at basal and at peak ethanol concentrations. The GABRA4 rs2229940 T/T genotype was associated to faster reaction times and with lower ethanol effects, determined as the difference between basal reaction time and reaction time at peak concentrations. All these associations remained significant after correction for multiple comparisons. No significant associations were observed for the common missense SNPs GABRB3 rs12910925, GABRG2 rs211035, GABRE rs1139916, GABRP rs1063310, GABRQ rs3810651, GABRR1 rs12200969 or rs1186902, GABRR2 rs282129, and GABRR3 rs832032.

Conclusions: This study provides novel information supporting a role of missense GABA-A receptor polymorphisms in reaction time, motor time and effects of low ethanol doses in vivo.

Age Effects in Postural Control Analyzed via a Principal Component Analysis of Kinematic Data and Interpreted in Relation to Predictions of the Optimal Feedback Control Theory

Optimal feedback control theory suggests that control of movement is focused on movement dimensions that are important for the task's success. The current study tested the hypotheses that age effects would emerge in the control of only specific movement components and that these components would be linked to the task relevance. Fifty healthy volunteers, 25 young and 25 older adults, performed a 80s-tandem stance while their postural movements were recorded using a standard motion capture system. The postural movements were decomposed by a principal component analysis into one-dimensional movement components, PM_k, whose control was assessed through two variables, N_k and σ_k, which characterized the tightness and the regularity of the neuro-muscular control, respectively. The older volunteers showed less tight and more irregular control in PM₂ (N₂: -9.2%, p = 0.007; σ₂: +14.3.0%, p = 0.017) but tighter control in PM₈ and PM₉ (N₈: +4.7%, p = 0.020; N₉: +2.5%, p = 0.043; σ₉: -8.8%, p = 0.025). These results suggest that aging effects alter the postural control system not as a whole, but emerge in specific, task relevant components. The findings of the current study thus support the hypothesis that the minimal intervention principle, as described in the context of optimal feedback control (OFC), may be relevant when assessing aging effects on postural control.

Kinematics and muscle activation patterns during a maximal voluntary rate activity in healthy elderly and young adults

BACKGROUND

Maximal voluntary rate (MVR) performance tasks can provide important age-related information to the limiting factors associated with movement and the development of fatigue.

AIM

To determine whether kinematic and muscle activation patterns during an MVR task differ between young and older adults.

METHODS

We continuously measured frequency, amplitude, peak velocity, index of co-contraction and median frequencies of the index finger flexors and extensors during a 20-s MVR task in 10 young and 10 older subjects.

RESULTS

Index finger amplitude and peak velocity in flexion and extension were significantly lower in the older group. During the MVR, amplitude was maintained in the old (1-4 s, 53.2° ± 2.8° vs. 15-19 s, 48.6° ± 3.2°, ns) but not in the younger group (1-4 s, 64.9° ± 4.9° vs. 15-19 s, 59.4° ± 3.3°; p = 0.001). Frequency declined in the young (1-4 s, 5.2 ± 0.24 Hz vs. 15-19 s, 4.4 ± 0.25 Hz; p = 0.001) and old (1-4 s, 4.6 ± 0.17 Hz vs. 15-19 s, 4.0 ± 0.15 Hz; p = 0.01). Similarly, peak flexion velocity of the young (1-4 s, 1.77 ± 0.07 × 10³ °/s vs. 15-19 s, 1.01 ± 0.07 × 10³ °/s, p = 0.01) and older groups (1-4 s, 1.04 ± 0.07 × 10³ °/s vs. 15-19 s, 0.78 ± 0.06 × 10³ °/s; p = 0.016) as well as peak extension velocity of the young (1-4 s, 1.01 ± 0.053 × 10³ °/s vs. 15-19 s, 0.78 ± 0.06 × 10³ °/s, p = 0.01) and older groups (1-4 s, 0.72 ± 0.04 × 10³ °/s vs. 15-19 s, 0.58 ± 0.05 × 10³ °/s, p = 0.012) significantly decreased throughout the MVR. Median frequency of the flexors and extensors were maintained and were not different between groups. Only the older group experienced an increase in the index of co-contraction.

CONCLUSION

The changes in kinematics over time are not a result of a decrease in pre-post test force or velocity, but rather central factors affecting movement coordination.

The aging brain: Movement speed and spatial control

BACKGROUND/OBJECTIVES

With aging, people commonly develop motor slowing (bradykinesia). Although this slowness with aging may be entirely related to degradation of the cerebral networks important in motor programing, it is possible that, at least in part, it may be a learned procedure for enhancing the accuracy and/or precision of movements. The goal of this study is to test these contradictory hypotheses.

METHODS

Twenty-four healthy adults, 12 younger than age 26 and 12 older than age 65 were asked to make alternative marks with a pen between a card centered in front of them and a series of circles distributed across a page. Performance was timed, and participants were instructed to complete the task as quickly as possible while not sacrificing accuracy for speed. The circle sizes and hand used varied by trial.

RESULTS

The older adults performed the task more slowly for all target circle diameters. As the circles decreased in size, the younger adults performed the task more rapidly than did the older participants, but the younger participants also had a greater decline in accuracy.

CONCLUSIONS

During this aiming task, healthy older adults were less likely than younger adults to sacrifice accuracy for speed. Thus, at least in part, their slowing may be a learned adaptive strategy.

Effects of Age and Task Load on Drivers' Response Accuracy and Reaction Time When Responding to Traffic Lights

Due to population aging, elderly drivers represent an increasing proportion of car drivers. Yet, how aging alters sensorimotor functions and impacts driving safety remains poorly understood. This paper aimed at assessing to which extent elderly drivers are sensitive to various task loads and how this affects the reaction time (RT) in a driving context. Old and middle-aged people completed RT tasks which reproduced cognitive demands encountered while driving. Participants had to detect and respond to traffic lights or traffic light arrows as quickly as possible, under three experimental conditions of incremental difficulty. In both groups, we hypothesized that decision-making would be impacted by the number of cues to be processed. The first test was a simple measure of RT. The second and third tests were choice RT tasks requiring the processing of 3 and 5 cues, respectively. Responses were collected within a 2 s time-window. Otherwise, the trial was considered a no-response. In both groups, the data revealed that RT, error rate (incorrect answers), and no-response rate increased along with task difficulty. However, the middle-aged group outperformed the elderly group. The RT difference between the two groups increased drastically along with task difficulty. In the third test, the rate of no-response suggested that elderly drivers needed more than 2 s to process complex information and respond accurately. Both prolonged RT and increased no-response rate, especially for difficult tasks, might attest an impairment of cognitive abilities in relation to aging. Accordingly, casual driving conditions for young drivers may be particularly complex and stressful for elderly people who should thus be informed about the effects of normal aging upon driving.

The Effects of Age, Gender, and Hand on Force Control Capabilities of Healthy Adults

OBJECTIVE

The present study examined the effects of age (20s to 70s), gender (male and female), and hand (dominant and nondominant) on force control capabilities (FCCs) in four force control phases (initiation, development, maintenance, and termination).

BACKGROUND

Normative data of FCCs by force control phase are needed for various populations in age and gender to identify a type of motor performance reduction and its severity.

METHOD

FCCs of 360 participants (30 for each combination of age group and gender) were measured using a finger dynamometer and quantified in terms of initiation time (IT), development time (DT), maintenance error (ME), and termination time (TT).

RESULTS

Although gradual increases (1%~28%) by age were shown in IT, DT, and TT, a dramatic increase in ME was observed among participants in their 50s (26%), 60s (68%), and 70s (160%) compared to those in their 20s~40s. The most distinctive interaction effect of age and gender was found in ME out of the four FCC measures. Lastly, hand and its related interactions were not found significant.

CONCLUSION

Normative FCC data were established for four age groups (20s~40s, 50s, 60s, and 70s) and gender.

APPLICATION

The normative FCC data can be used for evaluating an individual's motor performance, screening patients with brain disorders, and designing input devices triggered and/or operated by the finger.

Construct Validity of Functional Capacity Evaluation in Patients with Whiplash-Associated Disorders

PURPOSE

The construct validity of functional capacity evaluations (FCE) in whiplash-associated disorders (WAD) is unknown. The aim of this study was to analyse the validity of FCE in patients with WAD with cultural differences within a workers' compensation setting.

METHODS

314 participants (42% females, mean age 36.7 years) with WAD (grade I and II) were referred for an interdisciplinary assessment that included FCE tests. Four FCE tests (hand grip strength, lifting waist to overhead, overhead working, and repetitive reaching) and a number of concurrent variables such as self-reported pain, capacity, disability, and psychological distress were measured. To test construct validity, 29 a priori formulated hypotheses were tested, 4 related to gender differences, 20 related associations with other constructs, 5 related to cultural differences.

RESULTS

Men had significantly more hand grip strength (+17.5 kg) and lifted more weight (+3.7 kg): two out of four gender-related hypotheses were confirmed. Correlation between FCE and pain ranged from -0.39 to 0.31; FCE and self-reported capacity from -0.42 to 0.61; FCE and disability from -0.45 to 0.34; FCE and anxiety from -0.36 to 0.27; and FCE and depression from -0.41 to 0.34: 16 of 20 hypotheses regarding FCE and other constructs were confirmed. FCE test results between the cultural groups differed significantly (4 hypotheses confirmed) and effect size (ES) between correlations were small (1 hypothesis confirmed). In total 23 out of 29 hypotheses were confirmed (79%).

CONCLUSIONS

The construct validity for testing functional capacity was confirmed for the majority of FCE tests in patients with WAD with cultural differences and in a workers' compensation setting. Additional validation studies in other settings are needed for verification.

Fine motor skills of the hands in Polish and Czech female senior citizens from different backgrounds

The aim of the present study was an in-depth analysis of fine motor skills of the hands in elderly women from different socio-cultural backgrounds. The research also included analysis of the associations of age with the variables assessing right- and left-hand motor skills and its effect on hand performance asymmetry. The study examined 486 women over the age of 60. The study measured dominant and non-dominant hand performance using the motor performance series test battery (aiming, line tracking, inserting pins, tapping) from the Vienna test system. The best results in the tests assessing coordinated hand movements were achieved by the group of elderly women attending a University of the Third Age in Poland. This may be the result of a larger variety of physical activity programs offered at this type of institution. However, due to the cross-sectional design of the study, additional research of a longitudinal nature needs to be performed using the same sample of individuals to draw any definitive conclusions. Additionally, a decrease in the differences between dominant and non-dominant hand function with age was observed.

Movement sequencing in normal aging: speech, oro-facial, and finger movements

The manner and extent to which normal aging affects the ability to speak are not fully understood. While age-related changes in voice fundamental frequency and intensity have been documented, changes affecting the planning and articulation of speech are less well understood. In the present study, 76 healthy, cognitively normal participants aged between 18 and 93 years old were asked to produce auditorily and visually triggered sequences of finely controlled movements (speech, oro-facial, and manual movement). These sequences of movements were either (1) simple, in which at least two of the three movements were the same, or (2) complex, in which three different movements were produced. For each of the resulting experimental condition, accuracy was calculated. The results show that, for speech and oro-facial movements, accuracy declined as a function of age and complexity. For these movements, the negative effect of complexity on performance accuracy increased with age. No aging or complexity effects were found for the manual movements on accuracy, but a significant slowing of movement was found, particularly for the complex sequences. These results demonstrate that there is a significant deterioration of fine motor control in normal aging across different response modalities.

Influence of spatial accuracy constraints on reaction time and maximum speed of performance of unilateral movements

The goal was to study reaction time and maximal velocity of upper limbs of healthy young adults of both sexes during transition from a simple to a more involved task. Performance of dominant and non-dominant arms was recorded. Participants were 43 healthy, right-handed, untrained men (n=22) and women (n=21), 18-22 years old. The simple task required a single jerk-like movement. The involved task required both speed and accuracy where necessity for high speed of performance was emphasized. The effectiveness of transition between tasks was calculated for both reaction time and maximal velocity. No lateral differences were found. Men usually had a shorter reaction time on both tasks and a higher maximal velocity in the simple task. Women were more effective at modifying velocity.

Forward-backward postural protective stepping responses in young and elderly adults

OBJECTIVES

Protective steps are essential for fall avoidance. Most studies only examined forwards stepping despite considerable bio-mechanical and visual differences between the forwards and backwards directions. We assess forward-backward differences in protective steps in a young and elderly group.

METHODS

Protective stepping responses were elicited by a platform moving unpredictably either forwards or backwards. For control purposes, voluntary steps, in response to vibration cues on the forehead or occiput were also recorded. Reaction time (RT), length and angular velocity of the steps were measured in 13 young (age 19-35years) and 13 elderly (age 58-86years) healthy volunteers.

RESULTS

(i) Protective vs voluntary steps: protective steps were earlier, faster and longer than voluntary steps. (ii) Forwards-backwards differences: RT was quicker for backwards than forwards protective steps, in contrast to voluntary steps where RTs were similar in the two directions. (iii) Age difference: the elderly had universally slower steps and they generated shorter backwards than forwards protective steps.

CONCLUSIONS

Protective steps appear more robust than voluntary steps - they are earlier (shorter RT), longer and faster than voluntary steps, indicating an automatic rather than a volitional reaction. Backwards protective steps occur earlier than forwards; such promptness may have evolved out of bio-mechanical features which make falling backwards easier. Since our elderly subjects had an average age <70years, their slower and shorter protective backwards steps may represent the first abnormality in this rescue postural response. The findings in the elderly may partly depend on dysfunction in fronto-basal ganglia postural loops.

Interlimb practice and aging: coding a simple movement sequence

BACKGROUND/STUDY CONTEXT: The purpose was to determine if aging interacts with the coding of a simple spatial-temporal movement sequence.

METHODS

An interlimb practice paradigm (24 participants; 12 young adults [age: 23-29]; 12 old adults [age: 65-78]) was designed to determine the coordinate system (visual-spatial/motor) that is used to code the movement sequence. Practice was scheduled over 2 days involving either the same visual-spatial or the same motor coordinates. On Day 3, two retention tests (Day 1/Day 2) were conducted.

RESULTS

Keeping the motor coordinates the same during acquisition resulted in superior retention only for younger adults.

CONCLUSION

The data provide strong evidence that the motor code plays a dominant role in acquiring simple movement sequences for younger adults, but not for older adults.

Representational pseudoneglect: a review

Pseudoneglect, the tendency to be biased towards the left-hand side of space, is a robust and consistent behavioural observation best demonstrated on the task of visuospatial line bisection, where participants are asked to centrally bisect visually presented horizontal lines at the perceived centre. A number of studies have revealed that a representational form of pseudoneglect exists, occurring when participants are asked to either mentally represent a stimulus or explore a stimulus using touch in the complete absence of direct visuospatial processing. Despite the growing number of studies that have demonstrated representational pseudoneglect there exists no current and comprehensive review of these findings and no discussion of a theoretical framework into which these findings may fall. An important gap in the current representational pseudoneglect literature is a discussion of the developmental trajectory of the bias. The focus of the current review is to outline studies that have observed representational pseudoneglect in healthy participants, consider a theoretical framework for these observations, and address the impact of lifespan factors such as cognitive ageing on the phenomenon.

Self-Management of Wellness and Illness in an Aging Population

In this chapter, we review the last 10 years of literature on self-management of illnesses (acute/episodic and chronic) and wellness (e.g., health promotion). We focus on health self-management in the context of an aging population, wherein middle-aged adults are more likely to be managing wellness activities and older adults are often managing both maintenance of health and chronic illnesses. The critical issues related to self-management of health are discussed, including those imposed by health care demands and those stemming from individual differences in general abilities (e.g., motor, perception, cognition) and socioemotional characteristics. The dynamic relationship between theory and practice is highlighted. Health care demands reflect the nature of the illness or wellness activity and include managing comorbidities, symptoms, and medications; engaging in health promotion activities (e.g., exercise, diet); the required use of health technologies; the need for health-related information; and coordination of the care network. Individual differences in motor, perceptual, and cognitive abilities, as well as in the severity and complexity of the illness and the consequent demands, also impact how a person self-manages health. Cognitive abilities, such as decision making, knowledge, literacy (i.e., general, health, and e-health literacy), and numeracy are particularly implicated in the process of managing one’s own health and are especially important in the context of an aging population; therefore we give these cognitive abilities special attention in this chapter. Socioemotional characteristics, and attitudes and beliefs about one’s health, impact an individual’s self-management of health as well, impacting his or her motivation and goal-setting behaviors. Moreover, we discuss literature on interventions that have been used to improve self-management of health, and we examine the potential for technology. We conclude with guidelines for technology design and instruction, and discuss emerging themes.

Measures of fine motor skills in people with tremor disorders: appraisal and interpretation

People with Parkinson's disease, essential tremor, or other movement disorders involving tremor have changes in fine motor skills that are among the hallmarks of these diseases. Numerous measurement tools have been created and other methods devised to measure such changes in fine motor skills. Measurement tools may focus on specific features - e.g., motor skills or dexterity, slowness in movement execution associated with parkinsonian bradykinesia, or magnitude of tremor. Less obviously, some tools may be better suited than others for specific goals such as detecting subtle dysfunction early in disease, revealing aspects of brain function affected by disease, or tracking changes expected from treatment or disease progression. The purpose of this review is to describe and appraise selected measurement tools of fine motor skills appropriate for people with tremor disorders. In this context, we consider the tools' content - i.e., what movement features they focus on. In addition, we consider how measurement tools of fine motor skills relate to measures of a person's disease state or a person's function. These considerations affect how one should select and interpret the results of these tools in laboratory and clinical contexts.

Age effects on sensory-processing abilities and their impact on handwriting

Background.

Sensory-processing abilities are known to deteriorate in the elderly. As a result, daily activities such as handwriting may be impaired. Yet, knowledge about sensory-processing involvement in handwriting characteristics among older persons is limited.

Purpose

To examine how age influences sensory-processing abilities and the impact on handwriting as a daily performance.

Method.

The study participants were 118 healthy, independently functioning adults divided into four age groups: 31–45, 46–60, 61–75 and 76+ years. All participants completed the Adolescent/Adult Sensory Profile (AASP). Handwriting process was documented using the Computerized Handwriting Penmanship Evaluation Tool (ComPET).

Findings.

Age significantly affects sensory processing and handwriting pressure as well as temporal and spatial measures. Both handwriting time and spatial organization of the written product were predicted by sensory seeking. When examining age contribution to the prediction of handwriting by sensory processing, sensory seeking showed a tendency for predicting handwriting pressure (p = .06), while sensory sensitivity significantly predicted handwriting velocity.

Implications.

Age appears to influence sensory-processing abilities and affect daily performance tasks, such as handwriting, for which sensitivity and seeking for sensations are essential. Awareness of clinicians to sensory-processing deficits among older adults and examining their impact on broader daily activities are essential to improve daily performance and quality of life.

The relationship between Parkinson's disease and essential tremor: review of clinical, epidemiologic, genetic, neuroimaging and neuropathological data, and data on the presence of cardinal signs of parkinsonism in essential tremor

BACKGROUND

The possible relationship between essential tremor (ET) and Parkinson's disease (PD) has been controversial since the first description of PD. However, there is increasing evidence suggesting an overlap between these two disorders. The aim of this review is to examine the relationship between PD and ET, focusing on clinical, epidemiologic, genetic, neuroimaging, and neuropathological data, and the presence of cardinal parkinsonism symptoms in ET.

METHODS

We conducted a PubMed search for articles published between 1966 and November 2011 regarding the relationship between ET and PD and the presence of postural tremor in PD patients; the presence of rest tremor, rigidity, and slowed movements in ET patients is reviewed.

RESULTS

Clinical series, follow-up studies of ET patients, and case-control and genetic epidemiological studies indicate that ET is associated with increased risk for PD. Some neuroimaging studies and neuropathological reports suggest an association between the two diseases. ET patients show high prevalence of rest tremor, and at least seven studies described slowed movements (possibly related to cerebellar dysfunction and/or bradykinesia) in patients with ET.

DISCUSSION

There is reasonable epidemiological and clinical evidence to support a link between ET and PD, although it is not clear what factors predict ET patient risk for developing PD or, more rarely, of PD patients developing ET. Future multicentric and multidisciplinary studies including epidemiological, clinical, neuroimaging, genetic, and neuropathological assessments are required to understand these associations.

Human short-term exposure to electromagnetic fields emitted by mobile phones decreases computer-assisted visual reaction time

The worldwide dramatic increase in mobile phone use has generated great concerns about the detrimental effects of microwave radiations emitted by these communication devices. Reaction time plays a critical role in performing tasks necessary to avoid hazards. As far as we know, this study is the first survey that reports decreased reaction time after exposure to electromagnetic fields generated by a high specific absorption rate mobile phone. It is also the first study in which previous history of mobile phone use is taken into account. The aim of this study was to assess both the acute and chronic effects of electromagnetic fields emitted by mobile phones on reaction time in university students. Visual reaction time (VRT) of young university students was recorded with a simple blind computer-assisted-VRT test, before and after a 10 min real/sham exposure to electromagnetic fields of mobile phones. Participants were 160 right-handed university students aged 18-31. To assess the effect of chronic exposures, the reaction time in sham-exposed phases were compared among low level, moderate and frequent users of mobile phones. The mean ± SD reaction time after real exposure and sham exposure were 286.78 ± 31.35 ms and 295.86 ± 32.17 ms (P < 0.001), respectively. The age of students did not significantly alter the reaction time either in talk or in standby mode. The reaction time either in talk or in standby mode was shorter in male students. The students' VRT was significantly affected by exposure to electromagnetic fields emitted by a mobile phone. It can be concluded that these exposures cause decreased reaction time, which may lead to a better response to different hazards. In this light, this phenomenon might decrease the chances of human errors and fatal accidents.

More than just tapping: index finger-tapping measures procedural learning in schizophrenia

BACKGROUND

Finger-tapping has been widely studied using behavioral and neuroimaging paradigms. Evidence supports the use of finger-tapping as an endophenotype in schizophrenia, but its relationship with motor procedural learning remains unexplored. To our knowledge, this study presents the first use of index finger-tapping to study procedural learning in individuals with schizophrenia or schizoaffective disorder (SCZ/SZA) as compared to healthy controls.

METHODS

A computerized index finger-tapping test was administered to 1169 SCZ/SZA patients (62% male, 88% right-handed), and 689 healthy controls (40% male, 93% right-handed). Number of taps per trial and learning slopes across trials for the dominant and non-dominant hands were examined for motor speed and procedural learning, respectively.

RESULTS

Both healthy controls and SCZ/SZA patients demonstrated procedural learning for their dominant hand but not for their non-dominant hand. In addition, patients showed a greater capacity for procedural learning even though they demonstrated more variability in procedural learning compared to healthy controls. Left-handers of both groups performed better than right-handers and had less variability in mean number of taps between non-dominant and dominant hands. Males also had less variability in mean tap count between dominant and non-dominant hands than females. As expected, patients had a lower mean number of taps than healthy controls, males outperformed females and dominant-hand trials had more mean taps than non-dominant hand trials in both groups.

CONCLUSIONS

The index finger-tapping test can measure both motor speed and procedural learning, and motor procedural learning may be intact in SCZ/SZA patients.

Measuring motor speed through typing: a surrogate for the finger tapping test

Motor speed is an important indicator and predictor of both cognitive and physical function. One common assessment of motor speed is the finger-tapping test (FTT), which is typically administered as part of a neurological or neuropsychological assessment. However, the FTT suffers from several limitations, including infrequent in-person administration, the need for a trained assessor and dedicated equipment, and potential short-term sensory-motor fatigue. In this article, we propose an alternative method of measuring motor speed, with face validity to the FTT, that addresses these limitations by measuring the interkeystroke intervals (IKI) of familiar and repeated login data collected in the home during a subject's regular computer use. We show significant correlations between the mean tapping speeds from the FTT and the median IKIs of the nondominant (r = .77) and dominant (r = .70) hands, respectively, in an elderly cohort of subjects living independently. Finally, we discuss how the proposed method for measuring motor speed fits well into the framework of unobtrusive and continuous in-home assessment.

Assessment of Parkinson disease: what do we need to show neuroprotection?

To date, no pharmacological agent has convincingly demonstrated the ability to slow the progression of Parkinson disease (PD). The development of treatments that slow down the progressive degeneration of the nigrostriatal dopaminergic system (true neuroprotection), which is ultimately responsible for the patients' functional decline, has become one of the basic goals of PD research. In this review, we have attempted to analyze the role of different methods that measure PD severity (basically, clinical scales, timed tests, and neuroimaging techniques) in the evaluation of the "neuroprotection" provided by different types of treatment for the disease, on the basis of clinical evidence.

Effects of strength, endurance and combined training on muscle strength, walking speed and dynamic balance in aging men

The aim of this study was to examine effects of 21-week twice weekly strength (ST), endurance (ET) and combined (ST + ET 2 + 2 times a week) (SET) training on neuromuscular, endurance and walking performances as well as balance. 108 healthy men (56.3 ± 9.9 years) were divided into three training (ST; n = 30, ET; n = 26, SET; n = 31) groups and controls (C n = 21). Dynamic 1RM and explosive leg presses (1RMleg, 50%1RMleg), peak oxygen uptake using a bicycle ergometer (VO(2peak)), 10 m loaded walking time (10WALK) and dynamic balance distance (DYND) were measured. Significant increases were observed in maximal 1RMleg of 21% in ST (p < 0.001) and 22% in SET (p < 0.001) and in explosive 50%1RMleg of 7.5% in ST (p = 0.005) and 10.2% in SET (p < 0.001). VO(2peak) increased by 12.5% in ET (p = 0.001) and 9.8% in SET (p < 0.001). Significant decreases occurred in 10WALK in ST (p < 0.001) and SET (p = 0.003) and also in DYND of -10.3% in ST (p = 0.002) and -8% in SET (p = 0.028). The changes in C remained minor in all variables. In conclusion, ST and SET training produced significant improvements in maximal and explosive strength, walking speed and balance without any interference effect in SET. Significant but moderate relationships were observed between strength and dynamic balance and walking speed, while no corresponding correlations were found in the ET group.

Physical performance characteristics related to disability in older persons: a systematic review

BACKGROUND

Progressive disability develops with older age in association with underlying disease, comorbidity and frailty. Physical performance characteristics are important to improve the physical condition of older persons and therefore may be able to prevent or delay the onset of (progressive) disability. However lack of understanding of the physiology and etiology of functional decline leading to disability causes a problem in the development of effective preventive interventions. The aim of the present review is to determine which physical performance characteristics are determinants of disability in the older general population.

METHODS

We searched systematically the electronic databases of PubMed (MEDLINE), CINAHL, Cochrane Library, Psychlit and Embase for cohort studies and randomized controlled trials assessing disability in the older general population. Outcomes of interest were handgrip strength, upper and lower extremity function, balance gait and physical activity. The searching strategy resulted in 22 studies included in the present systematic review.

RESULTS

Although heterogeneity was present in the measurements of disability, consistent findings were shown for physical performance characteristics and disability. In general, a lower score of the physical performance characteristics was associated with a higher probability of (the development of) disability. The association for other aspects of gait (e.g. gait-step continuity, gait-step symmetry, path deviation and turning) and disability seems to be present, though the number of studies is limited.

CONCLUSION

In the present systematic review, associations were found for hand grip strength, upper and lower body strength, gait speed, physical activity and the probability of disability.