Examining the Link Between Cerebral Small-Vessel Diseases and Motor Symptoms in Parkinson Disease

A strong link has been identified between cerebral small vessel diseases (CSVDs) and motor symptoms in patients with Parkinson disease (PD), according to a recent cross-sectional study in Brain and Behavior.

Researchers discovered a significant relationship between axial motor impairments and deep white matter hyperintensities (DWMHs) of the frontal and occipital lobes of the brain. Prevalence of DWMHs in the frontal lobe was determined to be risk factor for the postural instability and gait disability (PIGD) phenotype.

The Unified Parkinson’s Disease Rating Scale evaluated 4 motor symptoms: tremors, rigidity, bradykinesia, and axial impairment. The Montreal Cognitive Assessment, as well as both the Hamilton Anxiety and Depression Scales, were used to evaluate nonmotor symptoms such as cognition, anxiety, and depression. Researchers used brain magnetic resonance imaging to assess subtypes of CSVDs, including lacunes, enlarged perivascular spaces (EPVSs), and white matter hyperintensities (WMHs). Classification of WMHs were split into DWMHs and periventricular hyperintensities. Analysis was performed to examine the effect that CSVDs had on motor symptoms.

Patients were separated into PIDG and non-PIDG groups based on ratios of their symptoms. The PIGD group was found to have higher scores for rates of tremor, bradykinesia, and axial motor impairments than the non-PIGD group.

CSVDs were found in all participants with different rates of occurrence and degrees of severity. Researchers found a strong association between EPVSs in the basal ganglia and the patient’s tremor score. Connections between each CSVD subtype and the 4 motor categories were analyzed by Spearman correlation analysis. It was found that the EPVS score in the basal ganglia region was closely correlated with the tremor score, whereas DWMH scores in the frontal and occipital lobe regions were closely correlated with the axial motor score.

Among all the clinical variables, the tremor and axial motor scores were most closely related to the amount of time passed since the onset of PD. In the multivariable linear analysis adjusting for PD duration, a significant link was found between tremor and EPVS scores in the basal ganglia region and also between the axial motor and DWMH scores in both the frontal and occipital lobe regions. However, bradykinesia and rigidity scores had no relationship with CSVD variables. Regardless of whether patients had lacunes near their basal ganglia or thalamus regions, there were no statistical differences in the 4 motor category scores.

The PIGD group demonstrated more serious cognitive impairment and DWMH in the frontal and occipital lobes than the non-PIGD group. It was found that cognitive impairment and DWMH in the frontal lobe were independent risk factors of the PIGD motor phenotype.

A total of 137 patients with PD were included in the study. Participants had a mean age of 68.1 years and 61.3% were male. The average recorded time since onset of PD was 5.2 years. Hypertension was the most common vascular risk factor, with an occurrence rate of 35%. History of stroke or a transient ischemic attack were the least common, with a prevalence rate of 2.9%. Lacunes were discovered in the basal ganglia in 43.8% of patients and in the thalamus of 20.4%.

Axial motor functions are a series of intricate motor behaviors consisting of locomotion, balance, and the ability to adapt to different environments. These behaviors are dependent on coordination of the entire central nervous system, which include the cortex, basal ganglia, thalamus, and cerebellum. Normal functioning of these components is required for correct posture, gait, and balance.

Reference

Wan Y, Hu W, Gan J, et al. Exploring the association between cerebral small‐vessel diseases and motor symptoms in Parkinson's disease [published online February 27, 2019]. Brain Behav. doi: 10.1002/brb3.1219.