Reversible laminar signal intensity in deep cortical gray matter in T1-weighted images and FLAIR after mild acute hyperammonemic hepatic encephalopathy.

Soporific acute hyperammonemic hepatic encephalopathy (aHE) can induce considerable changes in cerebral white and gray matter. This report describes a patient in the subacute phase of aHE grade I without disturbed consciousness and with reversible fine laminar cortical involvement on magnetic resonance imaging (MRI). The 59-year-old patient had esophageal varices bleeding due to primary biliary cirrhosis (ammonium blood level: 140 mmoL/L) and presented with sensory Jacksonian seizures, dysarthria, and increased drowsiness and fatigue. MRI revealed patchy hyperintense (T2-weighted, T2w) white-matter lesions and bilateral signal intensities in the striatum (T1w). During a rise of ammonium blood level to 220 mmoL/L, the patient had increased drowsiness, persistent dysarthria and mild temporary hemiparesis without loss of consciousness. Two weeks later, the patient was asymptomatic and blood ammonium level had reverted to normal value. MRI at that time revealed bihemispheric fine laminar subcortical hyperintensities on T2w and fluid-attenuated inversion recovery (FLAIR) imaging, and partially on T1w sequences, with no swelling or restricted diffusion; the hyperintensities were fully reversible a month later. Such a distinct cortical signal increase not only on T2w images, but also on T1w, in a patient after a mild form of aHE is a new MR finding.

Arm swing asymmetry in Parkinson's disease measured with ultrasound based motion analysis during treadmill gait.

The reduction of arm swing during gait is a frequent phenomenon in patients with early Parkinson's disease (PD). However, the objective quantification of this clinical sign using treadmill-based gait analysis has not been systematically evaluated so far. We simultaneously measured ultrasound based limb kinematics and spatiotemporal gait parameters during treadmill walking at different speeds in 21 early PD patients in Hoehn and Yahr (HY) stage I, 19 patients with bilateral PD in HY stage II and 25 age-matched controls. Both PD groups showed a highly significant reduction of the arm swing amplitude on the more affected body side (MAS). Decomposing total arm swing resulted in a bilateral decrease of arm retroversion in both PD groups, whereas anteversion was normal on the less affected side of the HY I cohort. Early stage patients exhibited a highly significant, almost threefold increase of the arm swing asymmetry index (I(A)) compared with controls. Reduced retroversion on the MAS and increased arm swing I(A) were the independent variables with the closest association to disease status in a multivariate logistic regression analysis. We conclude that ultrasound based motion analysis during treadmill walking allows reliable investigation of asymmetric arm movements in early PD patients which attenuate with ongoing disease. Impaired active arm retroversion seems to be the earliest sign of upper extremity dysfunction in parkinsonian gait. The measurement of limb kinematics during treadmill gait can broaden our methodological line-up for the analysis of complex motor programs in movement disorders.