Which Side of Your Body was First Hit with Parkinson Symptoms? It Makes a Difference.

On which side of your body did Parkinson symptoms first appear?  Apparently, it makes a difference, although different studies discovered different differences.

One recent study (“Side‐of‐onset of Parkinson’s disease in relation to neuropsychological measures“) gave a battery of tests to Parkies who experienced either Left-Onset Parkinson’s Disease (LOPD) or Right-Onset Parkinson’s Disease (ROPD).  Here’s what the researchers found for each group:

Left-Onset Parkinson’s Disease (LOPD)

• People with LOPD displayed significantly more anxiety than people with ROPD.
• On a test called “Digit Span Backwards” (where you listen to a string of single numbers – e.g., 7-4-9-2-1, and you have to repeat it in reverse order:  1-2-9-4-7), the LOPD crowd performed significantly worse than the ROPD group.

And what about Right Onset PD?

Right-Onset Parkinson’s Disease (ROPD)

•  The ROPD group showed a greater tendency towards “magical ideation.”

Discussion:

1.  What is the purpose of “Digit Span Backwards”?  Well, it’s part of a larger cognitive test that includes “Digit Span Forwards,” where you repeat numbers back in the same order you hear them (e.g., the tester says 7-4-9-2-1, and you say back 7-4-9-2-1).  According to the article, Digit Span Forward “is primarily a measure of short-term attention.”  However, Digit Span Backwards “expands on this to include working memory.”  So in this experiment, the authors are suggesting that people with LOPD are losing some of their executive function.   (Note:  I read elsewhere that if you want to score well on both these tests, it helps to visualize the numbers in your mind as the tester says them.)
2. What is “magical ideation”?  It sounds benign, doesn’t it?  Like, very Walt Disney.  Apparently, though, it’s part of a family of conditions that fall under the general terms “cognitive slippage” and “schizotypy.”  Wikipedia, the font of all knowledge, describes it thus:

“[Researchers] define Magical Ideation as magical and superstitious beliefs about reality reliant on false causal relations between events.  By this definition, cognitive slippage can manifest as fallacious, causal connections between correlated or unrelated events.”

Superstitious?  I’ll remember to purposefully take elevators to the 13th Floor going forward.  (In much of Asia, it’s the 4th Floor that you’re supposed to avoid, the number 4 equating with death.)

And now the big HOWEVER:  if you read different research, you see different results.  Everything depends on what study you read.  Another publication (“Cognitive differences between patients with left-sided and right-sided Parkinson’s disease. A review.“) came up with dissimilar outcomes.  Here’s the abstract:

“At disease onset, patients with Parkinson’s disease (PD) typically report one side of the body to be more affected than the other. Previous studies have reported that this motor symptom asymmetry is associated with asymmetric dopaminergic degeneration in the brain. Research on the cognitive repercussions of this asymmetric degeneration has yielded inconsistent results. Here, we review studies that reported on the cognitive performance of patients with left-sided (LPD) or right-sided (RPD) motor symptom predominance. We present evidence that patients with RPD typically experience problems with language-related tasks and verbal memory, whereas patients with LPD more often perform worse on tasks of spatial attention, visuospatial orienting and memory and mental imagery. In general, no differences were found between both groups on tasks measuring attention and executive function. The association between motor asymmetry and cognitive performance indicates that PD does not lead to one typical cognitive profile. The effect of symptom laterality on the cognitive complaints should be considered in the assessment and treatment of each individual patient.”

And yet another study (“Apathy in patients with Parkinson disease as a function of side of onset“) concluded:

“Clinically significant levels of apathy are much more likely to occur in patients with right-onset disease. These patients may be at greater risk of PD-related dementia.”

So what does this mean to us regular Parkies on the street?  Here’s what occurs to me:

• Hold onto this question (Does it make any difference which side of my body first exhibited Parkinson’s symptoms?) and bring it up in conversations with your doctor, your fellow Parkie friends, and anyone running a research study that you’re volunteering for.
• Ask your doctor what he/she thinks of this issue, and whether he/she thinks you should be trying different non-pharmacological therapies because of it.  More Sudoku?  More time on the spin bike?  Less time on the spin bike and more Rock Steady boxing?  More dinner parties?
• If you meet someone who can answer the question, ask the next question:  Does it make any difference if Parkinson symptoms first appeared on my left side, yet I’m right handed?
• Recognize that even if you’re dealing only with Right Onset Parkies (or Left Onset Parkies), you’re still going to see a lot of variation in symptoms and disease progression.
• In general, seize control of your life and do all the non-pharmacological fixes that you can:  be physically active, stay social, maintain good sleep hygiene, write poetry, play a musical instrument, etc.