To the Editor A recent Research Letter in JAMA Neurology1 presented results of a functional magnetic resonance imaging study of individuals with rare loss-of-function SCN9A mutations2 that abolish sensory neuron sodium channel Nav1.7 activity, resulting in congenital pain insensitivity. The study compared brain responses to a brief pinprick stimulus between patients (n = 2) and control individuals (n = 4). The authors reported activation of areas that have previously been implicated in pain processing and observed “no significant difference between patients and control individuals…across the entire pain matrix….”1 Although studying patients with loss-of-function SCN9A mutations is important and could potentially be highly informative, the conclusions to be drawn from the current study are limited for several reasons.
Büchel C, Geuter S, Sprenger C. Comparing Painful Stimulation vs Rest in Studies of Pain. JAMA Neurol. 2016;73(10):1258-1259. doi:10.1001/jamaneurol.2016.2989