Sleep Disturbance and Serum Ferritin Levels Associate with High Impulsivity and Impulse Control Disorders in Male Parkinson’s Disease Patients

Abstract

Impulse control disorders (ICDs) occur in a subset of Parkinson's disease (PD) patients on dopaminergic medications however there are currently no reliable markers to identify patients at risk. Sleep disturbances are more common in patients with an ICD. Serum ferritin levels have been associated with PD disease stage and progression, but have not previously been associated with impulsivity levels. The objective of this study was to determine if serum ferritin levels and sleep disturbance are associated with high traits of impulsivity and ICD in a cohort of PD patients attending a movement disorders clinic. This study assessed impulsiveness in 87 PD patients using the Barratt Impulsiveness Scale. Severity of sleep disturbance was determined using the sleep-related items of the MDS-UPDRS. Serum ferritin, iron and transferrin levels were measured in patients, as well as 36 age-matched healthy controls. Serum ferritin levels were significantly elevated in male PD patients in the high impulsivity group compared to patients in the low (p=.022) and normal range groups (p=.024) and showed a linear increase across the three groups. Sleep disturbance also demonstrated a linear trend, which was most severe in the high impulsivity group (p=.030). A subgroup of 11 male PD patients who fulfilled the DSM-5 criteria for an ICD had significantly higher ferritin levels and more severe sleep disturbance when compared with the remaining male PD cohort. Serum ferritin levels and sleep disturbance severity are highlighted as potential markers for abnormal impulsivity and ICD in PD patients.

Demographic and Clinical Predictors of Trait Impulsivity in Parkinson’s Disease Patients

“…Aligning with previous findings regarding PD-ICD subjects, the current study suggests that being of male gender is a significant risk factor for the development of trait impulsivity [ 19 , 20 ]. Male subjects displayed significant associations between disease severity and the BIS-11 second-order attentional and nonplanning subscales.…”

Trait Impulsivity as a Feature of Parkinson’s Disease Treatment and Progression

“…While male sex, no history of smoking, following secondary education, and more severe course of illness have been postulated as possible players, various studies are contradictory and often significance is lacking [ 31 ]. Recent studies are also suggestive of REM sleep behaviour disorders (RBDs) and sleep disturbances presenting an identifying factor for future ICD development [ 46 , 47 ]. Currently, classified as a prodromal stage of alpha-synucleinopathies, RBDs are also proposed to cause a more severe impairment in the mesocorticolimbic pathway, culminating in impairment of reward processing [ 47 ].…”