Botulinum toxin (BTX) is widely used to treat muscle spasticity by acting on motor neurons. Recently, studies of the effects of BTX on sensory nerves have been reported and several studies have been conducted to evaluate its effects on peripheral and central neuropathic pain. Central neuropathic pain includes spinal cord injury-related neuropathic pain, post-stroke shoulder pain, multiple sclerosis-related pain, and complex regional pain syndrome. This article reviews the mechanism of central neuropathic pain and assesses the effect of BTX on central neuropathic pain.

Kim DY, et al. Brain Neurorehabil. 2023 Jul;16(2):e18. https://doi.org/10.12786/bn.2023.16.e18

Objective To compare the accuracy of ultrasound-guided and non-guided botulinum toxin injections into the neck muscles involved in cervical dystonia.Methods Two physicians examined six muscles (sternocleidomastoid, upper trapezius, levator scapulae, splenius capitis, scalenus anterior, and scalenus medius) from six fresh cadavers. Each physician injected ultrasound-guided and non-guided injections to each side of the cadaver’s neck muscles, respectively. Each physician then dissected the other physician’s injected muscle to identify the injection results. For each injection technique, different colored dyes were used. Dissection was performed to identify the results of the injections. The muscles were divided into two groups based on the difficulty of access: sternocleidomastoid and upper trapezius muscles (group A) and the levator scapulae, splenius capitis, scalenus anterior, and scalenus medius muscles (group B).Results The ultrasound-guided and non-guided injection accuracies of the group B muscles were 95.8% and 54.2%, respectively (p<0.001), while the ultrasound-guided and non-guided injection accuracies of the group A muscles were 100% and 79.2%, respectively (p<0.05).Conclusion Ultrasound-guided botulinum toxin injections into inaccessible neck muscles provide a higher degree of accuracy than non-guided injections. It may also be desirable to consider performing ultrasound-guided injections into accessible neck muscles.

Background: Multigene panel sequencing (MGPS) is the first‐line option in diagnostic testing for genetically heterogeneous but clinically similar conditions, such as neuromuscular disorders (NMDs). In this study, we aimed to assess the utility of comprehensive NMD MGPS and the need for updated panels.Methods: All patients were analyzed by either of two versions of the NMD MGPS and by chromosomal microarray and karyotype testing. Four patients with negative NMD MGPS results underwent whole exome sequencing.Results: In total, 91 patients were enrolled, and a genetic diagnosis was made in 36 (39.6%); of these, 33 were diagnosed by the comprehensive NMD MGPS, two were confirmed by chromosomal microarray, and one was diagnosed by whole exome sequencing. For MGPS, the diagnostic yield of Version 2 (19/52; 36.5%) was a little higher than that of Version 1 (14/39; 35.9%), and one gene identified in Version 2 was not included in Version 1. A total of 36 definitive and nine possible causative variants were identified, of which 17 were novel.Conclusion: A more comprehensive panel for NMD MGPS can improve the diagnostic efficiency in genetic testing. The rapid discovery of new disease‐causing genes over recent years necessitates updates to existing gene panels.

Recently, temporal muscle thickness (TMT) has been investigated as a novel surrogate marker for muscle mass and function in neurologic patients. This study aimed to assess the correlation of TMT with grip strength to establish a new parameter for predicting pre-stroke sarcopenia. A total of 358 patients who were newly diagnosed with acute ischemic stroke at our institution between November 2021 and August 2022 were enrolled. Eighty-four patients met the eligibility criteria. The mean TMT was measured within initial brain MRI using previously described methods. Pearson's correlation analyses assessed the relationship between grip strength and TMT. Multiple logistic regression analyses were performed to identify associations between TMT and other associated factors including grip strength, sarcopenia risk, body mass index, age, Charlson Comorbidity Index and Geriatric nutrition risk index. Mean TMT values indicated a strong correlation with the grip strength of the non-hemiplegic hand in both male and female patients. Multiple logistic regression analyses showed that TMT was associated with grip strength and sarcopenia risk in hemiplegic patients. Measuring TMT using cranial MR images during the initial stages of stroke could help predict a patient's pre-stroke muscle strength status. Further studies are required to apply TMT in pre-stroke sarcopenia diagnosis.

Objective This study introduces a novel home-based dual-task platform incorporating augmented reality (AR), COGNIMO, aimed at simultaneously enhancing cognition and physical abilities. The purpose of this study was to assess the effectiveness of this intervention in enhancing cognitive and physical abilities in elderly individuals with subjective cognitive decline, mild cognitive impairment (MCI), and mild Alzheimer’s dementia.Methods A 12-week observational study enrolled 57 participants aged 60–85 years. Primary outcomes included changes in cognitive scores (Korean Mini-Mental State Examination, 2nd edition [K-MMSE-2] and Korean-Montreal Cognitive Assessment [K-MoCA]), while secondary outcomes measured physical parameters and depression scores between baseline and week 12 in the active and the control groups.Results Of 57 participants, 49 completed the study. The active group (≥12 sessions) exhibited significant improvement in K-MoCA compared to the control group (<12 sessions) (p=0.004), while K-MMSE-2 score changes showed no significant difference (p=0.579). Positive correlations between training sessions and K-MoCA changes were observed (r=0.31, p=0.038), emphasizing a dose-response relationship. Subgroup analyses revealed a distinction in cognitive changes, particularly in the MCI group.Conclusion The COGNIMO platform showed positive effects on cognitive function in MCI patients, suggesting potential benefits for this population. The study highlights the potential of AR-integrated home-based interventions for cognitive enhancement in elderly individuals, underlining the need for further trials in the future.