Search

Bimanual coordination is impaired in Parkinson's disease affecting patients' ability to perform activities of daily living and to maintain independence. Conveyance of information between cortical and subcortical areas is essential for bimanual coordination and relies on the integrity of cerebral microstructure. As pathological deposition of alpha-synuclein compromises microstructure in Parkinson's disease, we investigated the relationship between microstructural integrity and bimanual coordination using diffusion-weighted MRI in 23 patients with Parkinson's disease (mean age +/- standard deviation: 56.0 +/- 6.45 years; 8 female) and 26 older adults (mean age +/- standard deviation: 58.5 +/- 5.52 years). Whole-brain analysis revealed specific microstructural alterations between patients and healthy controls matched for age, sex, handedness, and cognitive status congruent with the literature and known Parkinson's disease pathology. A general linear model revealed distinct microstructural alterations associated with poor bimanual coordination in Parkinson's disease, corrected for multiple comparisons using a permutation-based approach. Integrating known functional topography, we conclude that distinct changes in microstructure cause an impediment of structures involved in attention, working memory, executive function, motor planning, motor control, and visual processing contributing to impaired bimanual coordination in Parkinson's disease. Loehrer et al. investigate the relationship between microstructural integrity and bimanual coordination in Parkinson's disease and healthy controls employing diffusion-weighted imaging. Whole-brain analysis revealed that alterations in structures involved in attention, working memory, executive function, motor planning, motor control and visual processing predicted impaired bimanual coordination in Parkinson's disease.

Objective: This study was undertaken to identify temporal encephaloceles (TEs) and examine their characteristics in patients with temporal lobe epilepsy (TLE) and ex- tratemporal lobe epilepsy (ETLE), as well as in asymptomatic cases. Methods: Four hundred fifty-eight magnetic resonance imaging scans were exam- ined retrospectively to identify TE in 157 patients with TLE, 150 patients with ETLE, and 151 healthy controls (HCs). Results: At least one TE was identified in 9.6% of the TLE patients (n = 15, 95% confidence interval [CI] = 5.3%–15.3%), in 3.3% of patients with ETLE (n = 5, 95% CI = 1.1%–7.6%), and in 2.0% of the HCs (n = 3, 95% CI = .4%–5.7%), indicating a significantly higher frequency in patients with TLE compared to ETLE and HC sub- jects (p = .027, p = .005). Examining the characteristics of TEs in both asymptomatic and epilepsy patients, we found that TEs with a diameter of less than 6.25 mm were more likely to be asymptomatic, with a sensitivity of 91.7% and a specificity of 73.3% (area under the curve = .867, 95% CI = .723–1.00, p = .001). Significance: Temporal encephaloceles may occur without presenting any clinical symp- toms. Patients with TLE show a higher frequency of TEs compared to the ETLE and HC groups. According to our study, TE size could be used to suggest potential epileptogenicity.

BACKGROUND AND PURPOSE: We evaluated cerebral white and gray matter changes in patients with iRLS in order to shed light on the pathophysiology of this disease. METHODS: Twelve patients with iRLS were compared to 12 age- and sex-matched controls using whole-head diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) techniques. Evaluation of the DTI scans included the voxelwise analysis of the fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). RESULTS: Diffusion tensor imaging revealed areas of altered FA in subcortical white matter bilaterally, mainly in temporal regions as well as in the right internal capsule, the pons, and the right cerebellum. These changes overlapped with changes in RD. Voxel-based morphometry did not reveal any gray matter alterations. CONCLUSIONS: We showed altered diffusion properties in several white matter regions in patients with iRLS. White matter changes could mainly be attributed to changes in RD, a parameter thought to reflect altered myelination. Areas with altered white matter microstructure included areas in the internal capsule which include the corticospinal tract to the lower limbs, thereby supporting studies that suggest changes in sensorimotor pathways associated with RLS.