An engineered glove for investigating the neural correlates of finger movements using functional magnetic resonance imaging

Assessing upper limb function in multiple sclerosis using an engineered glove

BACKGROUND AND PURPOSE

The importance of upper limb function in multiple sclerosis (MS) is increasingly recognized, especially for the evaluation of patients with progressive MS with reduced mobility. Two sensor-engineered gloves, able to measure quantitatively the timing of finger opposition movements, were previously used to assess upper limb disability in MS. The aims of the present study were: (1) to confirm the association between glove-derived variables and standard measures of MS disability in a larger cohort; (2) to assess the correlation with quantitative magnetic resonance imaging (MRI) and quality of life (QoL) measures; and (3) to determine if the glove-derived variables offer advantages over the standard measure for assessing upper limb function in MS, namely, the Nine-Hole Peg Test (9HPT).

METHODS

Sixty-five patients with MS, stable on disease-modifying treatment, were evaluated at baseline using the glove, and through clinical examination (Expanded Disability Status Scale, Symbol Digit Modalities Test, Timed 25-Foot Walk Test and 9HPT), MRI evaluation and QoL questionnaires. Correlations between the glove-derived variables and clinical, MRI and QoL variables were assessed using Spearman's rank correlation coefficient analysis.

RESULTS

Glove-derived variables significantly differed between patients with relapsing-remitting and those with progressive MS, with similar or slightly higher correlations of the 9HPT with clinical variables. We found greater correlations of the QoL physical component with glove-derived variables than with the 9HPT, and a significant correlation of its mental component with the glove-derived variables but not with the 9HPT.

CONCLUSION

The study results, confirming previous findings and showing advantages over the 9HPT, encourage the investigation of sensitivity to change in glove-derived variables in a longitudinal setting.

Neuroplasticity of the sensorimotor neural network associated with walking aid training in people with multiple sclerosis

The objective of this pilot study was to identify neural descriptors and correlates of participation in a multicomponent walking aid program, the Assistive Device Selection, Training and Education Program (ADSTEP), in people with multiple sclerosis, as reflected by resting state functional MRI. Fourteen people with multiple sclerosis who used a walking aid at baseline and reported falling at least once in the prior year were recruited from the multiple sclerosis clinic in a Veterans Affairs and the surrounding community to participate in a trial of ADSTEP, a multicomponent program of walking aid selection, fitting and six weekly progressive task-oriented walking aid training sessions and undergo resting state functional brain MRI. The functional MRI was performed at baseline and at program completion to assess for changes in neural connectivity of the sensorimotor neural network. Compared to baseline, following ADSTEP participation, functional connectivity between the supplementary motor areas and both the primary somatosensory cortices and the putamen was increased; whereas functional connectivity between the supplementary motor areas and the cerebellum was decreased. This study provides preliminary support for supraspinal sensorimotor neuroplasticity in response to rehabilitation interventions such as task-oriented walking aid training, suggests specific neural targets for future mobility interventions, and supports the need for full-scale randomized controlled trials in this area.

Quantitative assessment of finger motor performance: Normative data

Background

Finger opposition movements are the basis of many daily living activities and are essential in general for manipulating objects; an engineered glove quantitatively assessing motor performance during sequences of finger opposition movements has been shown to be useful to provide reliable measures of finger motor impairment, even subtle, in subjects affected by neurological diseases. However, the obtained behavioral parameters lack published reference values.

Objective

To determine mean values for different motor behavioral parameters describing the strategy adopted by healthy people in performing repeated sequences of finger opposition movements, examining associations with gender and age.

Methods

Normative values for finger motor performance parameters were obtained on a sample of 255 healthy volunteers executing sequences of finger-to-thumb opposition movements, stratified by gender and over a wide range of ages. Touch duration, inter-tapping interval, movement rate, correct sequences (%), movements in advance compared with a metronome (%) and inter-hand interval were assessed.

Results

Increasing age resulted in decreased movement speed, advance movements with respect to a cue, correctness of sequences, and bimanual coordination.

No significant performance differences were found between male and female subjects except for the duration of the finger touch, the interval between two successive touches and their ratio.

Conclusions

We report age- and gender-specific normal mean values and ranges for different parameters objectively describing the performance of finger opposition movement sequences, which may serve as useful references for clinicians to identify possible deficits in subjects affected by diseases altering fine hand motor skills.

How people with multiple sclerosis cope with a sustained finger motor task: A behavioural and fMRI study

Motor and non-motor basal ganglia (BG) circuits can help healthy subjects cope with task-induced central fatigue and re-establish motor performance after deterioration. This work aimed to assess whether patients with multiple sclerosis (MS) were able to recover motor performance after deterioration due to a demanding task and whether BG activity played a role in performance recovery in this population. Fourteen patients with MS performed a finger-tapping sequence with their right hand during three fMRI sessions: at baseline, after a demanding finger motor task (5-min sequence repetition) and after a short rest period. We observed deterioration of spatial and temporal accuracy with task repetition, as expected; after rest, temporal but not spatial accuracy recovered. Further, higher subjective fatigue was associated with increased motor performance deterioration and reduced temporal accuracy recovery. The amplitude of the BOLD signal change in the left caudate, putamen, globus pallidus, thalamus and amygdala was high at baseline and significantly reduced after the demanding task. Following rest, activity achieved values similar to the baseline in all these regions except for the amygdala. These findings suggest that patients were in a fatigue-like state since task beginning, as they showed enhanced BOLD signal change in the subcortical structures known to be recruited in healthy subjects only when coping with fatigue to recover motor performance. Abnormalities in motor and non-motor BG functions can contribute to fatigue in MS.

Prefrontal activity decline in women under a single dose of diazepam during rule-guided responses: an fMRI study

Daily life events confront us with new situations demanding responses to usual and unusual rules. Diazepam (DZ), a clinically important drug, facilitates the inhibitory activity of the GABAergic system. Prefrontal cortex, rich in DZ receptors, coordinates necessary resources to direct actions according to rules. The balance between excitatory and inhibitory activity is critical to achieve optimal function of brain systems leading to complex functions. Major sex differences in the physiological mechanisms of the GABAergic system have been reported. However, the differential influence of DZ on men and women in neural activity during behavior directed by frontal lobes remains unexplored. The ability of healthy volunteers to select responses following usual/congruent and novel/incongruent rules, and brain correlates were measured with fMRI under the administration of DZ and a placebo. 10 mg of DZ was enough to decrease the performance in a different manner between men and women. While reaction times increased in both men and women, women committed more errors selecting responses than men under DZ. Men demonstrated increased activity, while women demonstrated decreased activity in frontal regions involved in response selection of rules. These findings could have important consequences in understanding the differential influences of DZ between the sexes in complex daily life situations. More importantly, this study emphasizes the importance of understanding the differential effects on men and women of drugs widely employed by society, thereby achieves better therapeutic results and avoids side effects that the present study revealed to be different between sexes.

Frontoparietal cortex and cerebellum contribution to the update of actual and mental motor performance during the day

Actual and imagined movement speed increases from early morning until mid-afternoon. Here, we investigated the neural correlates of these daily changes. Fifteen subjects performed actual and imagined right finger opposition movement sequences at 8 am and 2 pm. Both actual and imagined movements were significantly faster at 2 pm than 8 am. In the morning, actual movements significantly activated the left primary somatosensory and motor areas, and bilaterally the cerebellum; in the afternoon activations were similar but reduced. Contrast analysis revealed greater activity in the cerebellum, the left primary sensorimotor cortex and parietal lobe in the morning than in the afternoon. Imagined movements in the morning significantly activated the parietal association cortices bilaterally, the left supplementary and premotor areas, and the right orbitofrontal cortex and cerebellum. In the afternoon, the frontal lobe was significantly activated with the right cerebellum. Contrast analysis revealed increased activity in the left parietal lobe in the morning than in the afternoon. For both tasks, speed in the morning was significantly related to the BOLD signal in the brain areas resulted more active. These findings suggest that motor performance is continuously updated on a daily basis with a predominant role of the frontoparietal cortex and cerebellum.