I’ve been noticing, recently, that my spatial perception on the left (the side currently affected by Parkinson’s) is different to that on the right. I seem to need more space on the left, and I feel uncertain about where things are on that side – or, rather, where I am in relation to them. I often bump into obstructions such as door jambs or newel posts when passing them on my left (I’ve always been a bit clumsy, but I haven’t noticed the disparity between left and right before).
I feel uncomfortable when somebody is standing close to my left hand side, and I frequently ask people to move away before I feel able to perform an action that involves my left hand side. My children are very obliging in this, but my husband wanted to know why – and I couldn’t really explain. After I caught a mention of faulty spatial awareness in Parkinson’s (I’m not sure where; it may have been an incidental mention on a forum), I realised that there was something going on here, and that it might be worth investigating.
One of the first articles I found was entitled “Freezing in Parkinson’s May Be Linked to Perception of Space“. It reports on a 2009 Canadian study of how people behaved on approaching doorways of varying widths (narrow, normal and wide). Three groups of people were included in the study: people with Parkinson’s who experienced freezing episodes, People with Parkinson’s who did not experience freezing episodes, and a control group of people without Parkinson’s.
Unsurprisingly, the narrow doorway caused the most problems.
“While approaching the door, these patients [Parkinson’s patients experiencing freezing] took shorter steps, had more gait variability, and tended to widen their base of support.
Parkinson’s patients with no freezing episodes were also affected by the narrow doorway and tended to widen their base of support.”
The lead researcher, Quincy Almeida, PhD, (Wilfrid Laurier University in Waterloo, Ontario, Canada) suggested that there might be “a sensory-perceptual mechanism that contributes to — and potentially even causes — the observable freezing episodes identified clinically”.
“Probably the most surprising finding is that even Parkinson’s patients who do not have issues with freezing can be profoundly influenced by the perception of an upcoming narrow doorway,” Dr. Almeida said.
“In other, normal-sized doorways, the typical Parkinson’s patient behaves much more like a healthy older adult with no hint of a change in walking pattern prior to the doorway. Yet in the narrow doorway, there is a shift in behavior and the nonfreezer behaves more like a freezer.”
I find this very interesting. It recalls one or two occasions when I have got temporarily “stuck” in a confined space that I should have been perfectly capable of clambering out of; I started to understand what was meant when people talk about their feet feeling as if they are stuck to the floor.
Another study, this time made by researchers in Reading, England, looked into the perception of space in Parkinson’s patients. Two control groups were included: people with rheumatoid arthritis (who also experience motor difficulties, albeit with a physical cause), and an age-matched group with no motor disorder. The study was performed via a questionnaire, and the findings indicate that those with Parkinson’s:
… do notice significant changes in their perception of the world around them, reporting problems with judging distance and motion in the street and problems reaching for objects and moving through narrow spaces within the home.[…]The results of the study suggest visuospatial deficits in PD which may involve the parietal lobe and have implications for understanding the way in which PD patients interact with their environment.
Abstract, Problems with perception of space in Parkinson’s disease: a questionnaire study by Alison Lee and John Harris, published in Neuro-Ophthalmology Jan 1999, Vol. 22, No. 1, Pages 1-15: 1-15.
So it seems that I’m not imagining the phenomenon, at the very least.
And just in case there are any disappointed Police fans out there, here is a link to the titular song.