NIRS to Diagnose SAMS

This proposal seeks to determine whether near infrared spectroscopy (NIRS) can differentiate between patients with confirmed SAMS and those with non-specific muscle complaints. NIRS is a non-invasive technique of assessing skeletal muscle tissue oxygenation and mitochondrial function. Mitochondrial dysfunction is a possible cause of SAMS, but NIRS has never been evaluated as a diagnostic tool for SAMS. Investigators will enroll 40 patients with a history of SAMS in an 8 wk randomized, double-blind crossover trial of simvastatin 20 mg/d and placebo separated by a 4 wk washout phase. Tissue oxygenation will be measured using NIRS during a short handgrip exercise protocol before and after each treatment period. Investigators will query patients about muscle complaints weekly during both phases of the study with a validated survey to assess muscle pain. Investigators will classify patients as testing positive for SAMS if they report pain on simvastatin and not placebo. Investigators hypothesize that these patients, vs. patients experiencing pain on both treatments, placebo, or neither treatment, will be distinguished by reduced tissue oxygenation during simvastatin treatment relative to placebo, demonstrating efficacy of NIRS as a clinical tool that can be eventually used for the diagnosis and ultimately treatment of SAMS.