Fatigue, Daytime Sleepiness, and Apathy Predict Fatigue Severity in PD

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In early Parkinson Disease, fatigue, excessive daytime sleepiness, and emotional apathy are predictive of increasing fatigue severity.

Higher base levels of fatigue, excessive daytime sleepiness, and emotional apathy early in the course of Parkinson disease (PD) are predictive of increasing fatigue severity over 1 year, according to study results published in Parkinsonism & Related Disorders.

In this study, researchers from Italy sought to investigate the course of fatigue over a 1-year period in 55 consecutive de novo patients with PD (age, 64.71±7.74 years). Participants had a disease duration of <2 years (mean disease duration, 14.56±8.43 months). Patients in this prospective longitudinal study were admitted as outpatients to a neurology department in Naples, Italy between March 2016 and October 2019.

Fatigue is one of the most common and disabling nonmotor symptoms associated with PD. Study researchers used the Italian version of the Parkinson Fatigue Scale (PFS) to assess this symptom at baseline and 1-year follow up. A PFS cut-off score of ≥3.09 defined clinically significant fatigue. Additionally, patients underwent examination including the Epworth Sleepiness Scale, Parkinson’s Disease Sleep Scale, Beck Depression Inventory, Parkinson’s Anxiety Scale, Apathy Evaluation Scale, and an extensive neuropsychological evaluation at baseline and 1 year.

Approximately 22% (n=12) of patients presented with fatigue at baseline, whereas 38% (n=21) of patients reported this symptom at 1-year follow up. The majority of patients with baseline fatigue (91%) had persistent fatigue. From baseline to 1 year, patients also reported an increase in prevalence for excessive daytime sleepiness (n=6-7, respectively) and emotional apathy (n=11-12). There was a decrease in the number of patients who reported depressive-anxious symptoms (from 21 to 17 patients) and sleep disorders (from 9 to 3 patients).

According to a multivariate regression analysis, baseline variables significantly predictive of fatigue severity at 1 year included fatigue (P <.01), daytime sleepiness (P <.01), and emotional apathy (P <.01).

Limitations of the study include its small sample size, single-center design, and the inclusion of a low number of patients with clinically significant fatigue.

The study investigators concluded that, ultimately, these research findings “could contribute to identify patients at risk for progression of fatigue, and suggest that treating emotional apathy and excessive daytime sleepiness might help to reduce worsening of fatigue.”


Siciliano M, Trojano L, De Micco R, et al. Predictors of fatigue severity in early, de novo Parkinson disease patients: A 1-year longitudinal study. Parkinsonism Relat Disord. Published online August 15, 2020. doi:10.1016/j.parkreldis.2020.08.019