Virtual Reality Feedback Cues for Improvement of Gait in Patients with Parkinson's Disease

Background: Our aim was to study the effects of visual feedback cues, responding dynamically to patient's self‐motion and provided through a portable see‐through virtual reality apparatus, on the walking abilities of patients with Parkinson's disease. Methods: Twenty patients participated. On‐line and residual effects on walking speed and stride length were measured. Results Attaching the visual feedback device to the patient with the display turned off showed a negligible effect of about 2%. With the display turned on, 56% of the patients improved either their walking speed, or their stride length, or both, by over 20%. After device removal, and waiting for 15 minutes, the patients were instructed to walk again: 68% of the patients showed over 20% improvement in either walking speed or stride length or both. One week after participating in the first test, 36% of the patients showed over 20% improvement in baseline performance with respect to the previous test. Some of the patients reported that they still walked on the tiles in their minds. Discussion: Improvements in walking abilities were measured in patients with Parkinson's disease using virtual reality visual feedback cues. Residual effects suggest the examination of this approach in a comprehensive therapy program

Two systems for empathy: a double dissociation between emotional and cognitive empathy in inferior frontal gyrus versus ventromedial prefrontal lesions

Recent evidence suggests that there are two possible systems for empathy: a basic emotional contagion system and a more advanced cognitive perspective-taking system. However, it is not clear whether these two systems are part of a single interacting empathy system or whether they are independent. Additionally, the neuroanatomical bases of these systems are largely unknown. In this study, we tested the hypothesis that emotional empathic abilities (involving the mirror neuron system) are distinct from those related to cognitive empathy and that the two depend on separate anatomical substrates. Subjects with lesions in the ventromedial prefrontal (VM) or inferior frontal gyrus (IFG) cortices and two control groups were assessed with measures of empathy that incorporate both cognitive and affective dimensions. The findings reveal a remarkable behavioural and anatomic double dissociation between deficits in cognitive empathy (VM) and emotional empathy (IFG). Furthermore, precise anatomical mapping of lesions revealed Brodmann area 44 to be critical for emotional empathy while areas 11 and 10 were found necessary for cognitive empathy. These findings are consistent with these cortices being different in terms of synaptic hierarchy and phylogenetic age. The pattern of empathy deficits among patients with VM and IFG lesions represents a first direct evidence of a double dissociation between emotional and cognitive empathy using the lesion method. Keywords: Emotional empathy; cognitive empathy; mirror neurons; inferior frontal gyrus; ventromedial prefrontal cortex Abbreviations: ANOVA = analysis of variance; BA = Brodmann area; EC = empathic concern scale; FS = fantasy scale; HC = healthy control; IFG = inferior frontal gyrus; IRI = Interpersonal Reactivity Index; MNS = mirror neuron system; PC = posterior lesion; PD = personal distress scale; PT = perspective-taking scale; ToM = Theory of Mind; VM = ventromedial prefrontal; WCST = Wisconsin Card Sorting Test

Two systems for empathy: A double dissociation between emotional and cognitive empathy in inferior frontal gyrus versus ventromedial prefrontal lesions

in inferior frontal gyrus versus ventromedial prefrontal lesion

Essential Tremor Prevalence is Low in the Druze Population in Northern Israel

Background: Essential tremor (ET) and Parkinson's disease (PD) are probably the most common movement disorders. As ethnic differences have been reported in ET, we designed the present study to evaluate the prevalence of ET and that of Parkinson's disease (PD) in the Druze villages of northern Israel. Methods: A two-phase, door-to-door survey was undertaken. Residents aged &ge;51 years who agreed to participate and answered &ldquo;yes&rdquo; to tremor or PD-related screening questions and 3% of subjects who screened negative were evaluated. Diagnostic criteria for ET were similar to those used in Sicilian and Spanish studies. PD was diagnosed according to Gelb's criteria. Results: The target population consisted of 9,086, the study cohort of 3,980 residents. Tremor was observed in 36 subjects. In 27, the tremor fully met the criteria for ET. The prevalence of ET (age &ge;65) was 1.49% (95% CI 0.91&ndash;2.07%). PD was diagnosed in 23 subjects. The prevalence of PD (age &ge;65) was 1.13 (95% CI 0.62&ndash;1.64%). Leucine-rich repeat protein kinase 2 (G2019S mutation) was evaluated in subjects diagnosed with tremor PD and those screened for assessment of the validity of the questionnaire. None carried the mutation. Discussion: The prevalence of ET in the Druze population is low and similar to the prevalence of PD.</div

Graph analysis uncovers an opposing impact of methylphenidate on connectivity patterns within default mode network sub-divisions

Abstract Background The Default Mode Network (DMN) is a central neural network, with recent evidence indicating that it is composed of functionally distinct sub-networks. Methylphenidate (MPH) administration has been shown before to modulate impulsive behavior, though it is not yet clear whether these effects relate to MPH-induced changes in DMN connectivity. To address this gap, we assessed the impact of MPH administration on functional connectivity patterns within and between distinct DMN sub-networks and tested putative relations to variability in sub-scales of impulsivity. Methods Fifty-five right-handed healthy adults underwent two resting-state functional MRI (rs-fMRI) scans, following acute administration of either MPH (20 mg) or placebo, via a randomized double-blind placebo-controlled design. Graph modularity analysis was implemented to fractionate the DMN into distinct sub-networks based on the impact of MPH (vs. placebo) on DMN connectivity patterns with other neural networks. Results MPH administration led to an overall decreased DMN connectivity, particularly with the auditory, cinguloopercular, and somatomotor networks, and increased connectivity with the parietomedial network. Graph analysis revealed that the DMN could be fractionated into two distinct sub-networks, with one exhibiting MPH-induced increased connectivity and the other decreased connectivity. Decreased connectivity of the DMN sub-network with the cinguloopercular network following MPH administration was associated with elevated impulsivity and non-planning impulsiveness. Conclusion Current findings highlight the intricate effects of MPH administration on DMN rs-fMRI connectivity, uncovering its opposing impact on distinct DMN sub-divisions. MPH-induced dynamics in DMN connectivity patterns with other neural networks may account for some of the effects of MPH administration on impulsive behavior