Postural asymmetry correlated with lateralization of cerebellar perfusion in persons with chronic stroke: A role of crossed cerebellar diaschisis in left side

Noninvasive cerebellar stimulation and behavioral interventions: A crucial synergy for post-stroke motor rehabilitation

BACKGROUND

Improvement of functional movements after supratentorial stroke occurs through spontaneous biological recovery and training-induced reorganization of remnant neural networks. The cerebellum, through its connectivity with the cortex, brainstem and spinal cord, is actively engaged in both recovery and reorganization processes within the cognitive and sensorimotor systems. Noninvasive cerebellar stimulation (NiCBS) offers a safe, clinically feasible and potentially effective way to modulate the excitability of spared neural networks and promote movement recovery after supratentorial stroke. NiCBS modulates cerebellar connectivity to the cerebral cortex and brainstem, as well as influences the sensorimotor and frontoparietal networks.

OBJECTIVE

Our objective was twofold: (a) to conduct a scoping review of studies that employed NiCBS to influence motor recovery and learning in individuals with stroke, and (b) to present a theory-driven framework to inform the use of NiCBS to target distinct stroke-related deficits.

METHODS

A scoping review of current research up to August 2023 was conducted to determine the effect size of NiCBS effect on movement recovery of upper extremity function, balance, walking and motor learning in humans with stroke.

RESULTS

Calculated effect sizes were moderate to high, offering promise for improving upper extremity, balance and walking outcomes after stroke. We present a conceptual framework that capitalizes on cognitive-motor specialization of the cerebellum to formulate a synergy between NiCBS and behavioral interventions to target specific movement deficits.

CONCLUSION

NiCBS enhances recovery of upper extremity impairments, balance and walking after stroke. Physiologically-informed synergies between NiCBS and behavioral interventions have the potential to enhance recovery. Finally, we propose future directions in neurophysiological, behavioral, and clinical research to move NiCBS through the translational pipeline and augment motor recovery after stroke.

Effects of intravascular photobiomodulation on cognitive impairment and crossed cerebellar diaschisis in patients with traumatic brain injury: a longitudinal study

The association between intravascular photobiomodulation (iPBM) and crossed cerebellar diaschisis (CCD) and cognitive dysfunction in patients with traumatic brain injury (TBI) remains unknown. We postulate that iPBM might enable greater neurologic improvements. The objective of this study was to evaluate the clinical impact of iPBM on the prognosis of patients with TBI. In this longitudinal study, patients who were diagnosed with TBI were recruited. CCD was identified from brain perfusion images when the uptake difference of both cerebella was > 20%. Thus, two groups were identified: CCD( +) and CCD( -). All patients received general traditional physical therapy and three courses of iPBM (helium-neon laser illuminator, 632.8 nm). Treatment assemblies were conducted on weekdays for 2 consecutive weeks as a solitary treatment course. Three courses of iPBM were performed over 2-3 months, with 1-3 weeks of rest between each course. The outcomes were measured using the Rancho Los Amigos Levels of Cognitive Functioning (LCF) tool. The chi-square test was used to compare categorical variables. Generalized estimating equations were used to verify the associations of various effects between the two groups. p < 0.05 indicated a statistically significant difference. Thirty patients were included and classified into the CCD( +) and CCD( -) groups (n = 15, each group). Statistics showed that before iPBM, CCD in the CCD( +) group was 2.74 (exp 1.0081) times higher than that of CCD( -) group (p = 0.1632). After iPBM, the CCD was 0.64 (exp-0.4436) times lower in the CCD( +) group than in the CCD( -) group (p < 0.0001). Cognitive assessment revealed that, before iPBM, the CCD( +) group had a non-significantly 0.1030 lower LCF score than that of CCD( -) group (p = 0.1632). Similarly, the CCD( +) group had a non-significantly 0.0013 higher score than that of CCD( -) after iPBM treatment (p = 0.7041), indicating no significant differences between the CCD( +) or CCD( -) following iPBM and general physical therapy. CCD was less likely to appear in iPBM-treated patients. Additionally, iPBM was not associated with LCF score. Administration of iPBM could be applied in TBI patients to reduce the occurrence of CCD. The study failed to show differences in cognitive function after iPBM, which still serves as an alternative non-pharmacological intervention.

Visual Occlusion Effects On Bipedal Stance Control In Chinese-Speaking Children With Dyslexia

Visual processing of complex character configurations is especially challenging for Chinese-speaking children with dyslexia (CSCD). The purpose of this study was to compare the effects of visual occlusion on postural control between dyslexic and non-dyslexic Chinese-speaking children by examining their visual-perceptual capacity and movement coordination with scale measures. Sixteen dyslexic children (10 males and, 6 females, 9.46 ± 1.26 yrs) and sixteen non-dyslexic children (10 males and 6 females, 9.91 ± 1.18 yrs) were recruited from the campus in Taiwan. Motor and visual perceptual performance were assessed with the Movement Assessment Battery for Children, 2nd Edition (MABC-2) and the Test of Visual-Perceptual Skills, 4th Edition (TVPS-4). Root mean square (RMS) and sample entropy (SampEn) of center of pressure (COP) were characterized during a bilateral upright stance with eyes open (EO) and eyes closed (EC). The results showed significant group differences in six of the seven TVPS-4 subscales (P < .001-.017) and one category of the MABC-2 (P = .006). In the EO condition, the children with dyslexia showed a greater RMS of COP specifically in the anterior-posterior (AP) direction than did the non-dyslexic children (P = .029). However, SampEn of COP in the two directions were not group dependent (P > .05). In the EC condition, RMS and SampEn of COP did not vary with group (P > .05). RMS of COP in the AP direction was negatively correlated with the sub-score of visual figure-ground in the TVPS-4 (r = - .381, P = .031). In summary, postural control of Chinese-speaking children with dyslexia is more affected with eyes open than with eyes closed, and the effect is related to visual disturbance of the foreground and background.

Voxel-based analysis of the metabolic asymmetrical and network patterns in hypermetabolism-associated crossed cerebellar diaschisis

Crossed cerebellar diaschisis (CCD) has been widely investigated in patients with supratentorial hypometabolism, however, the available evidence about the metabolic feature of CCD in patients with contralateral supratentorial hypermetabolism is lacking. This study aimed to assess the metabolic asymmetrical profile, network pattern and predisposing factors for the hypermetabolism-associated CCD, by using voxel-based asymmetry index (AI) and brain network analyses. Seventy CCD positive (CCD+) and 99 CCD negative (CCD-) patients with unilateral supratentorial hypermetabolism were introduced. Among different brain regions with AI_max or AI_min, striatum & thalamus was accompanied by the highest positive rate of CCD (85.7% or 70.1%, respectively). CCD+ group had significantly greater AI_max (median [IQR], 0.62 [0.44-0.84] vs. 0.47 [0.35-0.61]), supratentorial hypermetabolic volume (1183.5 [399.3-3026.8] vs. 386.0 [152.0-1193.0]) and hypometabolic volume (37796.5 [24741.8-53278.0] vs. 3337.0 [1020.0-17193.0]), and lower AI_min (-0.85 [-1.05--0.73] vs. -0.49 [-0.68--0.35]) compared with CCD- group (all P < 0.001). Logistic regression analysis manifested that patients with AI_min located at striatum & thalamus were 16.4 times more likely to present CCD than those at frontal lobe (OR = 16.393; 95% CI, 4.463-60.207; P < 0.001), and the occurrence of CCD was also associated with AI_max (OR = 49.594; 95% CI, 5.519-445.653; P < 0.001) and AI_min (OR = 3.133 × 10^-4, 95% CI, 1.693 × 10^-5-5.799 × 10^-3, P < 0.001). Brain network analysis indicated that the relative hypermetabolism in the contralateral supplementary motor cortex (SMC) and precuneus gyrus were constant in the CCD related patterns. These results demonstrated that the greater AI_max, lower AI_min and AI_min located at striatum & thalamus should be predisposing factors for CCD in patients with unilateral supratentorial hypermetabolism. Relative increased activities in the contralateral SMC and precuneus gyrus might be attributed to a compensatory mechanism for the abnormal brain network related to CCD.