Structural connectivity in a paediatric case of anarchic hand syndrome.

BACKGROUND: "Anarchic hand" is a rare condition characterised by non-volitional, goal-directed movements of one arm. We report a case with analysis of structural and functional connectivity. CASE PRESENTATION: A 15 year old girl developed intermittent symptoms of intermanual conflict or anarchic hand as a result of traumatic brain injury during which she sustained a callosal bleed. Resting-state fMRI and DTI tractography were performed at a stage when symptoms had largely resolved. CONCLUSION: Structural connectivity between homologous superior frontal areas and functional connectivity between homologous posterior cingulate areas were significantly reduced, which may have contributed to causation. Tractography demonstrated new indirect connections between supplementary motor areas via the cerebellum, which we propose contributed to symptom resolution.

Lewy body compared with Alzheimer dementia is associated with decreased functional connectivity in resting state networks.

Resting state functional magnetic resonance imaging (fMRI) was used to measure whole brain functional connectivity within specific networks hypothesised to be more affected in dementia with Lewy bodies (DLB) (a disease characterised by prominent attentional deficits, spontaneous motor features of parkinsonism and depression) than in Alzheimer׳s disease (AD) and controls. This study involved 68 subjects (15 DLB, 13 AD and 40 controls) who were scanned using resting state BOLD (blood-oxygen-level-dependent) fMRI on a 3T MRI scanner. Functional connectivity was measured using a model-free independent component analysis approach that consisted of temporally concatenating the resting state fMRI data of all study subjects and investigating group differences using a back-reconstruction procedure. Resting state functional connectivity was affected in the default mode, salience, executive and basal ganglia networks in DLB subjects compared with AD and controls. Functional connectivity was lower in DLB compared with AD and controls in these networks, except for the basal ganglia network, where connectivity was greater in DLB. No resting state networks showed less connectivity in AD compared with DLB or controls. Our results suggest that functional connectivity of resting state networks can identify differences between DLB and AD subjects that may help to explain why DLB subjects have more frequent attentional deficits, parkinsonian symptoms, and depression than those with AD.