Premorbid personality in frontotemporal dementia: Amyotrophic lateral sclerosis spectrum

Abstract

AbstractBackgroundFrontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are considered two clinical expressions of the same neurodegenerative continuum (FTD‐ALS spectrum) with common underlying pathology and genetics. Patients can present with pure behavioral/cognitive (FTD), pure motor (ALS) or mixed (FTD‐ALS) forms. The factors determining the development of one rather than the other phenotype are unknown. However, it is common observation that patients’ personality traits differ between the phenotypes: ALS patients tend to display a prosocial behavior characterized by kindness and agreeableness. On the opposite, FTD patients frequently present with disinhibition, anti‐social behaviors and lack of empathy. These traits are often described by patients’ relatives as having always characterized the patients’ personality. We therefore aimed at testing if FTD and ALS patients have different premorbid personalities, under the hypothesis that they reflect different vulnerabilities in the brain circuits related to social behavior and motor function, respectively.MethodWe prospectively recruited the patients presenting to our Memory and Motor Neuron Disease Clinics between December 2018‐December 2020. Patients’ personality was assessed through the NEO Personality Inventory 3 (NEO‐PI‐3), which analyses the five main personality factors (Neuroticism, Extraversion, Openness, Agreeableness, Conscientiousness). NEO‐PI‐3 was administered to patients’ caregivers with reference to the patient’s personality at two timepoints: at diagnosis and 15 years prior to symptoms onset. Differences in personality factors between groups at each timepoint were tested with ANOVA.Result46 consecutive patients (30 FTD, 13 ALS, and 3 FTD‐ALS assigned to the FTD or ALS group, based on their first symptom) were recruited. A significant difference in premorbid personality emerged in the Openness domain, showing that ALS patients (mean value 153±15) had been more open to new experience, ideas and emotions than FTD patients (132±21 ‐ p=0.049), even many years before symptoms onset. Such difference in Openness was decreased at the current moment but persisted (147±16 vs 123±24, p= 0.06).Conclusionwe found that premorbid personality profile differed in FTD and ALS patients in at least one personality domain (Openness), supporting the hypothesis that premorbid personality may represent a vulnerability marker to the development of behavioral or motor disturbances. Our finding needs to be further explored with imaging.