Movement disorders: perivascular space and Parkinson's disease are closely related

The perivascular space (PVS) is the fluid-filled space around the blood vessels of the brain and is an important channel
for the brain's fluid and lymphatic waste removal system.
In patients with neurodegenerative diseases and in mouse models studying amyloid clearance, there is clinical and preclinical evidence that PVS visible on magnetic resonance imaging (MRI) is a hallmark
of cerebral small vessel disease and dysfunction of sugar clearance.

Figure 1: Paper cover image

In addition to PVS visible on MRI, other well-established neuroimaging-based markers of cerebral small vessel disease include periventricular and deep leukoplasia (WMHs).

In Parkinson's disease (PD), PVS burden (BG-PVS) in the basal ganglia region has been recognized as a potential indicator
of the progression of movement disorders and cognitive decline.
However, results on cognition have been mixed, with some studies reporting no clear correlation
with PVS visual burden scores.
Unfortunately, many of these studies assessed BG-PVS using qualitative visual rating scales, which were more susceptible to rater bias and upper and lower bound effects
.

Interestingly, two large population-based studies showed a pathophysiological difference between large (>3 mm in diameter) and small (≤3 mm in diameter) PVS, although not specifically demonstrated
in PD.
The results of the North Manhattan study showed that the high burden of small PVS was associated with an increased risk of future vascular events, while the AGES-Reykjavik study showed that large PVS was associated with
reduced information processing speed and an increased risk of dementia.

In this way, Joel Ramirez et al.
of the University of Toronto explored the association
between quantitative measures, global cognition, and motor/non-motor features of large and small BG-PVS in a multicenter cohort of PD patients.

They looked at the association
between large and small BG-PVS in 133 Parkinson's disease patients enrolled in the Ontario Neurodegenerative Disease Research Program with the Association of Movement Disorders' Uniform Parkinson's Disease Rating Scale (MDS-UPDRS) Parts I-IV and cognition (Montreal Cognitive Assessment).

Figure 2: Graph of paper results

They found that PD patients with small BG-PVS were associated with MDS-UPDRS Part I (P = 0.
008) and Part II (both P = 0.
02), while patients with large BG-PVS were associated
with MDS-UPDRS Part III (P < 0.
0001) and Part IV (P < 0.
001).

BG-PVS is not associated with
cognitive ability.

The significance of the study lies in the fact that small BG-PVS is associated with motor and non-motor experiences in daily life, while large BG-PVS is associated with
motor symptoms and motor complications.

Credit:
Ramirez J, Berberian SA, Breen DP, et al.
Small and Large Magnetic Resonance Imaging–Visible Perivascular Spaces in the Basal Ganglia of Parkinson’s Disease Patients .
_Movement Disorders_.
Published online April 11, 2022:mds.
29010.
doi:[10.
1002/mds.
29010](https://doi.
org/10.
1002/mds.
29010)