"Understanding (PD) is like trying to put together a puzzle with pieces that don't fit" -Dave Guerrero.
The thing we must first remember is that dementia is defined as loss of previously acquired skills e.g. washing dishes, cooking, driving etc. Parkinson’s dementia does not occur in typically until late stages. This means that patients would have had a diagnosis and symptoms of Parkinson's for over 10-15 years before dementia sets in. If anyone has symptoms of dementia present earlier than this than chances are the disease they have is not typical, common garden variety Parkinson's but a variant which could include things like PD plus syndromes (MSA, CBGD, LBD) or another dementia disorder such as FTD or Alzheimer's and PD as well as other neurological diseases that can have parkinsonism, like strokes. Having said this, all patients notice a change in their cognition from the very beginning of the disease even before motor symptoms are noticeable.
Does this mean there is dementia? No!
The usual symptoms I am referring to that patients commonly experience are related to personality such as getting more irritable, short tempered, anxious and depressed. Sometimes, we as patients may not realize these subtle changes like increase impatience; but those close to us notice and may call it to our attention or become aware of these changes before we do. At the onset of my PD, I began to notice increased irritability and frustration especially when working at the office which I could not understand since I was the queen of multitasking. I was NOT alone in my perception my staff of many years also noticed a change in my personality that was out of character for me and something was wrong! Fortunately, this symptom improves with treatment. But, is one of the first signs of PD in most people and if not careful can go untreated for years.
Second, all Parkinson's medications can cause cognitive changes usually in the form of brain fogginess, sedation, trouble with word finding, and depression which can cause forgetfulness. This is why is imperative to make only one medication change at a time and follow up with your doctor shortly after every new medication change to evaluate outcome and most importantly tolerability. Be on the lookout for cognitive problems due to medications, these symptoms will come on within a week of staring new medicine typically and will aggravate or worsen after each dose intake within a few hours and last as long as medication Effect lasts. This is why it is important to pay attention to medicines and a keep chart of times and effects of all medicines and talk to your doctor if you notice cognitive changes. But be sure, not make changes or discontinue regimen without first discussing with your physician.
Third, because PD usually affects mood as in depression as well as sleep, as in restless leg (RLS), sleep apnea, REM behavior, these if not properly treated can by themselves cause memory loss usually in the form of poor concentration which leads to short term memory loss because one cannot encode information into long term when not paying attention due to being tired, sleepy or fatigued, plus it is through deep sleep that our brain processes all information and makes long term memories.
Fourth, just as our bodies become slow so do our brains in retrieving information, pulling and opening the file cabinets where information is stored can be difficult. It does not mean is lost simply means that takes a little longer. Solution increasing dopa and mental exercises-
Fifth, however after a number of years as PD advances, up to 50 % of patients have a chance of developing PD dementia which is characterized by psychiatric tones like delusions, psychosis, hallucinations (visual) along with apathy and pronounced forgetfulness. Treat with Acadia; anticholinesterase (e.g. Aricept, Exelon); Provigil (among other stimulants); Namenda as well as antipsychotics (Clozaril).
In my experience as a Parkinson's doctor, patient, and caregiver the overwhelming problems with memory in the majority of PD patients, unless they are end -stage disease beginning to hallucinate becoming apathetic which are signs of early dementia setting in, are a combination of Parkinson's disease itself as well as medication (usually not enough). The result of insufficient dopa in the brain as well as not properly treating and addressing non- motor symptoms which interfere with concentration is poor memory. Thus, long term memory appears impaired because the majority of PD patients are sleepy, depressed, under- and- over -medicated, as well as fatigued. Early recognition of all non- motor symptoms of PD which includes side effects of medications as well as early detection of PD dementia is key, after all even the hardest puzzles have a solution.
Finally, I recommend every patient have a baseline MMSE (mini mental status exam) or Mocha test followed by every year unless symptoms of forgetfulness and apathy or other sings of forgetfulness arise. If depression is significant and can't tell if memory problems are due to depression or early onset of dementia recommend Neuropsychiatric evaluation. If a person has profound depression unresponsive to meds consider ECT (electroconvulsive therapy) which works great.
The basic understanding of the various puzzle pieces which make up memory and cognitive changes in PD along with the correct treatment will lead to improved quality of life along with decrease chances for nursing home placement or prolonged hospitalizations.
