Certain Nonmotor Symptoms Predict Anxiety In Parkinson’s

Cognitive function, motor impairments not associated with the mood disorder

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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REM sleep behavior disorder and autonomic dysfunction were predictive of anxiety in Parkinson's patients in a three-year study.

REM sleep behavior disorder (RBD) and autonomic dysfunction (dysautonomia), two types of nonmotor Parkinson’s disease symptoms, were significant predictors of anxiety in Parkinson’s patients over a three-year study.

More than half (57%) of patients in in the study met the clinical criteria for anxiety at some point, underscoring its prevalence among people with the neurodegenerative disease.

“Future research should confirm the direction and mechanisms underlying these relationships, including the potential for anxiety symptom reduction through treatment for RBD and dysautonomia,” the researchers wrote.

The study, “Predictors of anxiety in Parkinson’s disease: results from a 3‑year longitudinal cohort study,” was published in Neurological Sciences.

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Anxiety is a common nonmotor symptom of Parkinson’s, occurring in nearly half of patients at some point in their lives. It can lead to worse emotional well-being, impaired daily functioning, and quality of life declines, all of which can contribute to burdens on patients and their caregivers.

While risk factors for developing anxiety have been proposed, only a couple longitudinal analyses have been done and the predictors aren’t well established.

“Understanding predictors of anxiety symptoms in [Parkinson’s] may help us to identify patients at risk for anxiety disorders,” the researchers wrote, noting symptom burden could be reduced by interventions that targeted “modifiable predictors” of anxiety.

Prevalence, predictors of anxiety in Parkinson’s

Researchers at the University of Virginia investigated the prevalence and predictors of anxiety symptoms in Parkinson’s patients over three years.

A total of 105 participants with Parkinson’s, but without a clinical diagnosis of dementia, were recruited from the university’s outpatient movement disorders clinic starting in March 2013, with evaluations lasting until September 2019. The patients (62 men, 43 women; mean age 67.8) had been living with the disease for a median of just under five years.

Patients completed a baseline visit at the study’s start and up to three follow-ups, each about a year apart. At each visit, they completed assessments that covered motor, psychiatric and cognitive symptoms.

Anxiety symptoms, assessed by the Beck Anxiety Inventory (BAI) questionnaire, were the primary outcome of interest. A higher BAI score generally reflects greater anxiety, with a score of 12 or more indicating a clinical anxiety disorder in Parkinson’s.

At baseline, the mean BAI score was 10.8, below the cutoff for anxiety. A total of 40 patients met the criteria for an anxiety disorder at that time. The mean BAI score increased each year, reaching a mean of 13.64 among the 67 patients who completed the three-year follow-up. Overall, 60 (57%) met the criteria for an anxiety disorder at some point.

Indicators of RBD and dysautonomia were significant independent predictors of anxiety over time in final statistical analyses. Both have been linked to anxiety in Parkinson’s previously, the researchers said.

Dysautonomia refers to abnormalities in the autonomic nervous system, which controls involuntary bodily processes such as heart rate and sweating, leading to gastrointestinal problems, sexual dysfunction, and abnormal heartbeat, among other symptoms.

RBD is a type of sleep disorder wherein patients physically act out behaviors during dreaming, something that’s suppressed during healthy sleep.

For every unit increase on the REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ) — reflecting more signs of RBD — a 0.05 point BAI increase was seen.

“In practice, clinicians may consider prioritizing anxiety screening for newly diagnosed [Parkinson’s] patients with RBD,” the researchers wrote, adding that “treatment for RBD may help to reduce anxiety symptoms in people with [Parkinson’s].”

Scores on the Scales for Outcomes in Parkinson’s-Autonomic Dysfunction (SCOPA-AUT) questionnaire were also linked to BAI. For every one unit increase in the SCOPA-AUT — reflecting more autonomic symptoms — BAI scores increased by 0.043.

The BAI and SCOPA-AUT assess for some similar symptoms, such as dizziness and lightheadedness, that can be signs of anxiety as well as autonomic dysfunction, making it difficult to untangle the two. Nonetheless, “treatment for autonomic dysregulation can improve self-reported anxiety symptoms,” the researchers wrote.

Other clinical factors, including cognitive function, motor impairments, and antidepressant use were not significantly associated with anxiety in the final statistical analyses. Cognitive impairment has been previously linked to anxiety, and as a result, this relationship “should be re-examined in future studies,” the researchers wrote.

The researchers noted future studies should seek to replicate their findings with additional diagnostic measures and evaluate the effects of interventions targeting these anxiety-predictors on anxiety symptoms.