Working memory, attention and planning abilities in NKX2.1-related chorea

Background: Although NKX 2.1 related chorea has been considered benign due to the favourable course of motor phenotype during life, the neurological condition is not limited to chorea, including non-motor symptoms in the developmental, cognitive and psychiatric domain. Aim of our study was to test working memory, attention and planning abilities of a cohort of NKX2.1 choreic patients compared to healthy controls. Methods: patients and healthy controls were assessed for working memory (Visual Digit Span test), response inhibition and sustained attention (Cued Go/No-Go test), and spatial problem-solving and planning task (Tower of London test). For experimental protocol, we used a computer based tool for neuropsychological experiments, Inquisit 5.0 software (Millisecond Software®). Non-parametric tests were performed for statistical analysis. Results: six patients and fifteen healthy paediatric controls were recruited. In the Digit Span test, both in forward and backward recall, patients showed statistically significant lower scores than controls. In the Cued Go/No-Go test as well as in the Tower of London, NKX 2.1 patients showed similar scores in the error rate and total score respectively, whereas in both tests they appeared to be slower than controls suggesting a poor performance in the execution of the tests. Conclusions: our findings demonstrate that patients with NKX2.1-related chorea show a selective impairment in working memory with increased latencies in both planning and attention. A developmental alteration of the cholinergic neurotransmission in the basal forebrain and the disruption of striatal networks could explain, at least in part, this neuropsychological profile.