Impaired dual-task gait in Parkinson's disease is associated with brain morphology changes

In Parkinson's disease (PD), impaired gait and cognition affect daily activities, particularly in the more advanced stages of the disease. This study investigated the relationship between gait parameters, cognitive performance, and brain morphology in patients with early untreated PD. 64 drug-naive PD patients and 47 healthy controls (HC) participated in the study. Single- and dual-task gait (counting task) were examined using an expanded Timed Up & Go Test measured on a GaitRite walkway. Measurements included gait speed, stride length, and cadence. A brain morphometry analysis was performed on T1-weighted magnetic resonance (MR) images. In PD patients compared to HC, gait analysis revealed reduced speed (p < 0.001) and stride length (p < 0.001) in single-task gait, as well as greater dual-task cost (DTC) for speed (p = 0.007), stride length (p = 0.014) and cadence (p = 0.029). Based on the DTC measures in HC, PD patients were further divided into two subgroups with normal DTC (PD-nDTC) and abnormally increased DTC (PD-iDTC). For PD-nDTC, voxel-based morphometric correlation analysis revealed a positive correlation between a cluster in the left primary motor cortex and stride-length DTC (r = 0.57, p = 0.027). For PD-iDTC, a negative correlation was found between a cluster in the right lingual gyrus and the DTC for gait cadence (r=-0.35, pFWE = 0.018). No significant correlations were found in HC. The associations found between brain morphometry and gait performance with a concurrent cognitive task may represent the substrate for gait and cognitive impairment occurring since the early stages of PD.

Cortical and subcortical morphometric changes and their relation to cognitive impairment in isolated REM sleep behavior disorder

OBJECTIVE

To date, very few studies have focused on structural changes and their association with cognitive performance in isolated REM sleep behaviour disorder (iRBD). Moreover, the results of these studies are inconclusive. This study aims to evaluate differences in the associations between brain morphology and cognitive tests in iRBD and healthy controls.

METHODS

Sixty-three patients with iRBD and thirty-six controls underwent MRI with a 3 T scanner. The cognitive performance was assessed by a comprehensive neuropsychological battery. Based on performance, the iRBD group was divided into two subgroups with (iRBD-MCI) and without mild cognitive impairment (iRBD-NC). The high-resolution T1-weighted images were analysed using an automated atlas segmentation tool, voxel-based (VBM) and deformation-based (DBM) morphometry to identify between-group differences and correlations with cognitive performance.

RESULTS

VBM, DBM and the comparison of ROI volumes yielded no significant differences between iRBD and controls. In the iRBD group, significant correlations in VBM were found between several cortical and subcortical structures primarily located in the temporal, parietal, occipital lobe, cerebellum, and basal ganglia and three cognitive tests assessing psychomotor speed and one memory test. Between-group analysis of cognition revealed a significant difference between iRBD-MCI and iRBD-NC in tests including a processing speed component.

CONCLUSIONS

iRBD shows deficits in several cognitive tests that correlate with morphological changes, the most prominent of which is in psychomotor speed and visual attention as measured by the TMT-A and associated with the volume of striatum, insula, cerebellum, temporal lobe, pallidum and amygdala.

Profile of cognitive deficits in schizophrenia and factor structure of the Czech MATRICS Consensus Cognitive Battery

We aimed to validate the Czech version of the MATRICS Consensus Cognitive Battery (MCCB). The MCCB is a test battery designed to assess cognitive treatment effects in clinical trials of patients with schizophrenia. The valid, reliable and replicable measurement of cognition in schizophrenia is of substantial importance for such clinical trial studies. We performed a psychometric analysis of the MCCB composite and domain scores based on ROC analysis of 67 schizophrenia patients and 67 age- and education-matched healthy controls from a total sample of 220 controls. Also, we correlated MCCB variables with scales measuring psychosocial functioning (Personal and Social Performance scale; PSP). The internal consistency of all 10 tests in the MCCB battery was good (Cronbach's α = 0.85 (95% CI [0.83, 0.88])). The discriminative validity for the detection of neurocognitive dysfunction in schizophrenia based on the area under the curve of MCCB composite T-score was ≥90% (95% CI [0.85, 0.96]) and all MCCB domains showed ps < .001. The MCCB global composite and the Speed of Processing domain score significantly predicted the PSP ratings. A confirmatory factor analysis on the whole control sample (N = 220) showed an optimal fit for a 6-factor in comparison to 1-factor solution. In conclusion, we found high discriminative validity for the Czech MCCB version, similar to the differentiation of schizophrenia versus healthy control groups in the original MCCB studies. We also established the factorial validity of the MCCB and showed that the overall composite of the MCCB predicts psychosocial functioning in the patient group.