Reward (BIS/BAS) mechanisms and fatigue in patients on chronic hemodialysis

Recently, it has been demonstrated that chronic inflammation could have a role on fatigue onset in chronic hemodialysis (HD). Research on neuro-immune interactions highlighted that an alteration of basal ganglia functioning, secondary to chronic inflammation, may translate in a reduced motivation and altered reward processes in chronic diseases. This study investigated a possible correlation between fatigue severity and reward mechanisms, that regulate motivational dispositions, in HD patients. Evaluation scales were administered to ninety-four patients on HD (54 Male, 40 Female; Mdage = 67±26.5; Dialytic Mdage in years = 4±6.3. Fatigue was assessed by using Fatigue Severity Scale (FSS). Behavioural Inhibition System (BIS) and Behavioural Activation System (BAS) Scale was administered to investigate approach/avoidance behaviours. Anxiety and depression were measured by State-Trait Anxiety Inventory (STAI-Y) and Beck Depression Inventory (BDI-II). Results show that the distribution of HD patients for FSS score did not show a normal pattern. FSS score was significantly higher in patients with high BIS Z-score than in patients with low and medium BIS Z-score. BDI score and STAI-Y scores were similar among BIS Z-score groups of patients. Findings suggest that in patients on chronic hemodialysis there is a correlation between fatigue severity symptoms and motivational disposition mechanisms that predispose to action inhibition.