Availability, accessibility, and affordability of neurodiagnostic tests in 37 countries.

Objective: To determine the availability, accessibility, and affordability of EEG, EMG, CSF analysis, head CT, and brain MRI for neurologic disorders across countries.

Methods: An online, 60-question survey was distributed to neurology practitioners in 2014 to assess the presence, wait time, and cost of each test in private and public health sectors. Data were stratified by World Bank country income group. Affordability was calculated with reference to the World Health Organization's definition of catastrophic health expenditure as health-related out-of-pocket expenditure of >40% of disposable household income, and assessment of providers' perceptions of affordability to the patient.

Results: Availability of EEG and EMG is correlated with higher World Bank income group (correlation coefficient 0.38, test for trend p = 0.046; 0.376, p = 0.043); CSF, CT, and MRI did not show statistically significant associations with income groups. Patients in public systems wait longer for neurodiagnostic tests, especially MRI, EEG, and urgent CT (p < 0.0001). The mean cost per test, across all tests, was lower in the public vs private sector (US $55.25 vs $214.62, p < 0.001). Each drop in World Bank income group is associated with a 29% decrease in the estimated share of the population who can afford a given test (95% confidence interval -33.4, 25.2; p < 0.001). In most low-income countries surveyed, only the top 10% or 20% of the population was able to afford tests below catastrophic levels. In surveyed lower-middle-income countries, >40% of the population, on average, could not afford neurodiagnostic tests.

Conclusions: Neurodiagnostic tests are least affordable in the lowest income settings. Closing this "diagnostic gap" for countries with the lowest incomes is essential.