Visuospatial but Not Verbal Working Memory Deficits in Adult Patients With Neurofibromatosis Type 1

Objective: Cognitive dysfunction is one of the main symptoms of neurofibromatosis type 1 (NF1). As an important advanced cognitive function, working memory (WM) has rarely been systematically analyzed in NF1 by isolating the particular domain of WM, and existing data involving WM in adults with NF1 are insufficient. This study aimed to investigate the characteristics of different subgroups of WM in NF1 from the perspective of the adult population. Method: We comprehensively analyzed WM in both verbal and visuospatial WM domains by using the N-back task (including the verbal N-back task and the visuospatial N-back task) in 31 adults with NF1 and 34 healthy controls (HCs) matched for age, gender, education levels and general cognitive status. The accuracy and reaction times (RTs) in the N-back task were entered into repeated-measure ANOVAs. Results: Compared with HCs, adults with NF1 presented significantly lower mean accuracy (F(1,62) = 4.60, p = 0.036) and longer RTs (F(1,62) = 4.91, p = 0.03) in the visuospatial N-back task, and the gap became more obvious as the difficulty levels increased. However, no significant difference was found in the verbal N-back task (accuracy: F(1,62) = 2.41, p = 0.13; RTs: F(1,62) < 1). Conclusions: Our study found that adults with NF1 had selective deficits in WM (impaired visuospatial but not verbal WM), and visuospatial WM dysfunction became obvious as memory load increased. Our findings supplement and refine the existing data on WM in NF1 disorder and demonstrate functional independence between verbal and visuospatial WM.