Background: What is the number and size of motor units, and axonal excitability profile in the early stages of muscle weakness in ALS compared to controls? Methods: We enrolled ALS patients with APB manual strength testing rated four or four-minus (ALS:4-arm) and four-plus (ALS:4+ arm) and control participants >35 years-old from the University of Toronto, University of Alberta and Universidade Federal de Sao Paulo. Mean±SD, one-way ANOVA and ANCOVA of ALSFRS-R, PUMN Score, MUNIX, MUSIX, and nerve-excitability testing using QTRAC TROND protocol were reported. Results: Twenty-five ALS patients and 63 controls were included. Mean MUNIX was significantly lower (p<0.0001) and MUSIX was significantly higher (p<0.001) in both ALS groups compared to controls. Mean strength-duration time constant in the ALS:4- arm (0.50ms±0.11; p<0.05) and superexcitability in both ALS groups (ALS:4- -29.05%±9.24, ALS:4+ -27.67%±8.03; p<0.05) were relatively increased, supporting axonal hyperexcitability. Conclusions: Significant motor unit loss measured by MUNIX is already present at the earliest detection of muscle weakness in ALS. Increased MUSIX and altered axonal physiology are associated with axonal sprouting and geometry change(1), along with ion channel dysfunction(2). Future trials targeting muscle weakness in ALS should consider the altered neuronal physiology during early disease stages and utilize neurophysiological biomarkers only in normal-to-mildly weak muscles.

Background: Walking aids such as crutches, canes and walkers are used by 2 million Canadians. Repetitive weight-bearing with walking aids may cause upper limb peripheral nerve injury. The objectives of this review were to: 1) identify types of nerve injuries reported with walking aids; 2) report electrodiagnostic findings; 3) identify typical treatment strategies; and 4) determine expected recovery time for such injuries. Methods: MEDLINE, EMBASE, CINAHL and Cochrane Library were searched for primary data in English published between 1950-2022. Abstracts were reviewed independently by 2 authors. Full-text reviews were independently conducted by 2 authors. Results: The search identified 3746 abstracts, 43 of which underwent full-text review. 31 studies were included. There were 144 cases of peripheral nerve injury. Crutches caused the most injuries (n=21 studies). The ulnar nerve was most commonly injured (n=27 cases). Improper walking aid fit was identified as a risk factor in 74% of cases. Stopping walking aid use was the most common treatment strategy (n=10 studies). Follow-up reports (n=20) indicated 65% of patients experienced recovery at 6 months. Conclusions: Improper walking aid fit and use were identified as major injury risk factors. A national program to teach patients and clinicians how to use walking aids may reduce injury risk.

Background: The burden and outcome of stroke in indigenous populations is less well understood. This review evaluates ischemic stroke outcomes in indigenous populations as compared to the general population in the context of recent advances in ischemic stroke therapy. Methods: The OVID Medline and EMBASE databases were searched for this review. Clinical outcome was measured using standardized outcome scale (eg. mRS) at 90 days following stroke intervention in indigenous as compared to non-indigenous adult populations. Results: 897 studies were identified, with 4 studies included in the final analysis. A total of (n=68895) patients were included who underwent thrombolysis. Study populations from Australia, New Zealand, United States and Canada comprised of (n=2012) indigenous patients. Mortality was significantly higher in indigenous populations as compared to non-indigenous (Odds Ratio-1.28, 95% CI-1.12; 1.46). The odds ratios of atrial fibrillation (1.26, 95% CI-1.12;– 1.41), diabetes (1.43, 95% CI- 1.27; 1.62), hypertension (1.33, 95% CI- 1.17; 1.51) and IHD (0.71, 95% CI- 0.62; 0.81) in indigenous patients was significantly higher than in non-indigenous patients. Conclusions: Indigenous populations undergoing stroke therapy are at a significantly increased risk of mortality as compared to non-indigenous populations. Comorbidities including diabetes, atrial fibrillation and hypertension are more prevalent in indigenous populations.