Cognitive functioning in children with pantothenate-kinase-associated neurodegeneration undergoing deep brain stimulation

AIM To examine the cognitive functioning of young people with pantothenate-kinase-associated neurodegeneration (PKAN) after pallidal deep brain stimulation (DBS). PKAN is characterized by progressive generalized dystonia and has historically been associated with cognitive decline. With growing evidence that DBS can improve motor function in adults and children with PKAN, there is now the opportunity to study the cognitive profiles of these patients over time. METHOD We present a case series of seven children (mean age 11y 7mo, SD 3y 2mo) undergoing bilateral pallidal DBS for the management of severe PKAN-associated dystonia. We administered standardized measures of intellectual ability and memory where possible, before DBS and 1 to 4 years after DBS. RESULTS No cognitive decline was observed and scores improved in all but one child (whose dystonia could not be adequately controlled owing to multiple medical problems). In line with a stabilization or reduction in their dystonia, all but one child was able to tolerate longer assessment sessions and complete either the same or a greater number of subtests. INTERPRETATION These findings suggest that apparent cognitive impairments may reflect difficulties in accessing cognition owing to severity of dystonia. Intellectual decline previously associated with PKAN may have been overestimated.