Behavior Impacts of Parkinson's Symptoms

Most people are aware of the tremors and other motor symptoms associated with Parkinson’s disease (PD), but the cognitive aspects of the condition often receive much less attention.

For those with PD, understanding cognitive symptoms like apathy and impulsivity can be vital to improving their quality of life.

A UK study led by David J. Ahearn, MRCP, of the Department of Elderly Medicine, Wythenshawe Hospital in Manchester, England explored impulsivity and apathy as symptoms of Parkinson’s disease.

The researchers concluded that there were separate clinical profiles for those with PD that experienced apathy and impulsivity with some overlap.

Discuss all Parkinson's disease symptoms with your doctor.

The study included 99 PD patients recruited from clinics in northwest UK. Criteria for inclusion in the study were that the patient experienced decreased cognitive efficiency after the onset of motor symptoms in more than one area, such as attention, planning, spatial relationships, memory and language.

The patients were then evaluated using several scales and tests. The Apathy Evaluation Scale was used to assess cognitive, behavioral and emotional apathy, and the 30 question Barratt Impulsiveness Scale (BIS) was used to measure non-planning impulsiveness, motor impulsiveness (acting without thinking) and cognitive impulsiveness.

The characteristics of each participant’s disease were assessed for age of onset, duration of motor symptoms, motor severity and complexity of symptoms by the Unified Parkinson’s Disease Rating Scale (UPDRS).

Current psychiatric symptoms were assessed using the Hospital Anxiety and Depression Scale (HADS) Neuropsychiatric Inventory (NPI) and South Oaks Gambling Screen (SOGS).

Cognition was assessed using the Mini-Mental State Exam (MMSE) The MMSE was also used to rule out any participants with dementia for inclusion in the study.

Of the 99 participants enrolled in the study, 35 participants were identified as having one or more impulse control disorder (ICDs). ICDs manifest as a reduced ability to control impulses like gambling, sex, spending and eating.

Dr. Ahearn and team found that apathy was significantly associated with age, age of motor symptom onset, disease stage, motor symptom severity and depression. Impulsivity was significantly associated with age of motor symptom onset, gambling and anxiety scores and motor complications.

The age of motor symptom onset had a positive correlation with apathy and a negative correlation with impulsivity. In other words, those who first experienced Parkinson’s disease later in life were more likely to have symptoms of apathy and less likely to have symptoms of impulsivity, and vice versa.

The researchers concluded that there were separate patient profiles for apathy and impulsivity in PD. However, they noted an overlap of apathy and impulsivity in some participants that may suggests difficulty in motivation and reward processes.

There were several limitations to the study. The BIS was a self-rated study that may include bias in responses and any apathy or impulsive behavior stemming from a personality trait rather than the PD could not be accounted for.

The study was published in the April issue of Current Gerontology and Geriatrics Research.

Some funding for the study was provided through grants from Parkinson’s UK. No other conflicts of interest were reported.