The Peripheral View: Neuromuscular Diagnosis, Care and Surveillance in Global Health

Dear Editor,

Before COVID-19 two recent pandemics were notably associated with infectious and para-infectious neuromuscular sequelae, including associations between acute flaccid myelitis (AFM) and West Nile Virus, and Guillain Barré Syndrome (GBS) and Zika virus (ZIKV). Yet, despite origins in sub-Saharan Africa (SSA), there is no evidence that these diseases, or other arboviruses for that matter, cause neurologic morbidity in the sub-continent. In the case of ZIKV, an argument has been made for newly acquired neurovirulence through viral evolution into African and Asian lineages, but weak healthcare systems and poor ability to surveil for outbreaks of GBS and AFM are also plausible explanations in areas with limited neuromuscular disease (NMD) expertise and diagnostic access and high rates of HIV, tuberculosis, malnutrition and other exposures presenting with similar neurologic morbidity.¹

With the exceptions of pediatric poliomyelitis and HIV-associated neuropathies, NMDs are vastly under-characterized in tropical and LMIC settings; ergo, most are entirely omitted from the global burden of neurologic disease studies and from policy and resource allocation decisions to address neurologic care capacity needs.^{2, 3} There have been recent calls for inclusion of ethnically diverse populations in NMD genomics research, but these calls are largely focused on capacity-building for biomedical research infrastructure, development of and collaboration between locally-based biorepositories, and growing local scientific genetic expertise and retention. A parallel investment in developing the clinical expertise to accurately diagnose, phenotype and care for patients with neuromuscular disease is also requisite.

For NMD diagnosis, the clinical examination, imaging and other diagnostic modalities cannot replace NCS/EMG for diagnosis and phenotypic characterizations. Despite its essential role as a neurodiagnostic test, surveys of both LIC and LMIC countries with neurology training programs found self-reported NCS/EMG competency to be lower than competencies in any other essential neurodiagnostic skill (lumbar puncture performance, CSF diagnostics, evaluation of CT/MRI, and EEG).⁴ Nearly half of neurology training program respondents in LIC countries reported no NCS/EMG skills. Operationalizing NMD clinical care and therapeutic access in low resource settings requires re-evaluation of training models requiring extended clinical and subspecialty training for electrodiagnostic skill acquisition. Task-shifting, a process wherein medical services typically provided by a highly-skilled medical professional are delegated to lower-skilled healthcare workers, is often employed to expand access to healthcare services in resource-constrained settings. In the case of NCS/EMG, even in settings of relative resource-wealth maintaining high quality studies independent of subspecialty training in electrodiagnostic (EDX) medicine is often a concern. Because of the dynamic nature of the EDX consultation, incorporating history and exam along with NCS/EMG findings as they are uncovered during testing, task-shifting to non-specialists is more challenging for NCS/EMG than for other neurodiagnostic modalities. For example, magnetic resonance imaging and electroencephalography generally utilize technicians to independently acquire data for review and interpretation by an offsite subspecialist. In areas with shortages of essential healthcare workers, the need for physical presence of an EDX medicine expert for interpretation of NCS and performance of EMG is a non-negligible barrier to NMD research and clinical care.

In Zambia, a pilot program is underway to diversify the EDX workforce to include physiotherapists with advanced training in needle EMG and EDX interpretation to overcome this barrier. Increasing access to teleneurology services may facilitate a task-sharing model with remote EDX specialists available for more complex consultations. We have also successfully trained research personnel to perform screening examinations for distal symmetric polyneuropathies in both rural and urban community settings, suggesting that engagement of non-physician community healthcare workers can facilitate diagnosis and early interventions for more common NMDs, and facilitate referrals for those with ‘red flags’ requiring further diagnostic evaluations or specialist expertise. Such efforts would be greatly aided by development of locally relevant diagnostic algorithms and austere interventions based on neuro-epidemiologic research conducted in these settings.

In areas with a lack of general neurology services, the EDX consultation may seem out of phase with capacity-building needs for general neurology. However, healthcare systems, inherently relying on human resources, do not necessarily need to follow a linear or even stepwise capacity-building approach to have substantial impact. Access to subspecialty care in resource-constrained settings has been associated with decreased “brain-drain,” through improved job satisfaction and decreased burnout among other healthcare workers, as well as enhancing medical education among local trainees, all of which contribute to better patient outcomes and community trust—value added beyond direct patient-subspecialist interactions.⁵

In the present era of pandemics and advancing environmental change, we must recognize the important role of neuromuscular morbidity and mortality in disease surveillance and global and regional health security. Opportunities for scientific discovery may follow and benefit global communities with prior precedents, such as study of the ALS/Parkinsonism-dementia complex in Guam⁶ and GBS in northern China⁷— both of which provided an epidemiologic basis for understanding genetic, immune, and environmental contributions to the pathophysiology of these disorders.

The WHO global polio eradication initiative serves as a successful model as well as a potential operational platform for such work. Given the consequences, building NMD expertise and EDX capacity for NMD in LMIC settings is not a peripheral step for either local or global communities.