Female gender doubles executive dysfunction risk in ALS: a case-control study in 165 patients

Background Cognitive impairment, mainly characterised by executive dysfunction, occurs in about half of cases in amyotrophic lateral sclerosis ( ALS). There is evidence that gender influences some clinical features of the disease, but its influence on the cognitive spectrum is unknown. Our objective was to investigate the impact of gender on cognitive profiles of patients with ALS. Methods A retrospective study based on an exhaustive neuropsychological battery was performed in a group of 165 ( 70 females, 95 males) sporadic, non-demented patients with ALS compared with 134 healthy control participants. This assessment primarily focused on executive, memory and language functions. Results 47 ( 29%) patients revealed impairment in executive function and 30 ( 18%) patients revealed cognitive non-executive impairment. Independent from mood tone and clinical variables, a significantly greater executive impairment was determined in female patients than in male patients and control participants. The relative risk for ALS females having impairment in executive function compared with male patients was 2.6 ( 95% CI 1.6 to 4.4; p=0.0003). ALS females scored lower in Phonemic Fluency, Trial Making, and Wisconsin Card Sorting test. Conclusions Results highlight a significant vulnerability of ALS female patients to develop cognitive dysfunctions peculiar to the disease, independently of bulbar onset. The explicative hypotheses of the data are focused on two interpretative lines not mutually exclusive: the role of gonadal hormones and gender-related brain asymmetry pre-existing to the disease. These findings, never reported before in the literature, can have important implications for models of ALS pathogenesis and for future clinical trial designs.