Cognitive Testing for DBS Surgery Is Unproven and Can Be Counterproductive
Earlier this year, my neurologist referred me to a neuropsychologist for a four-hour assessment to ascertain whether I qualify to undergo Deep Brain Stimulation (DBS) for Parkinson’s disease (PD).
This practice is the industry standard. For example, the Parkinson’s Foundation says that neuropsychological testing is strongly recommended before proceeding with DBS. The Michael J. Fox Foundation tells its callers that this practice is mandatory.
Before addressing the merits of my assessment, it should be noted that no standardized neuropsychological test for DBS currently exists. Even defining what constitutes a disqualifying cognitive dysfunction remains an open question.
And more damning, there is no study that compares the decline in specific cognitive conditions from DBS surgery to the decline of those conditions in a control group of patients who did not receive DBS. It is likely that both groups would see a decline. But is the difference, if any, statistically significant? Additionally, what is the magnitude of the difference? Over what time period?
Most studies try to show deterioration after DBS surgery for certain conditions. This is not the proper benchmark, but even so the results are inconsistent.
Thus, the reality is that there is a lack of a definition of the cognitive conditions for testing, a lack of statistically significant results, a lack of a reliable estimate of the magnitude of the effect, and a lack of an identified time period in which any statistically significant differences would occur. If subjected to the standard FDA review process, neuropsychological testing as a necessary precursor to DBS would fail.
Having said that, my own experience provides some first-hand insight into the murky world of neuropsychology.
My assessment begins with the statement: “The patient’s medical history is significant for Parkinson’s disease (2001), hemangioma, orthostatic hypotension, and head injuries and subdural hematomas (11/2020)”.
The key findings of the assessment were that:
1) Mr. Zecola could not follow a multi-stage command
2) His simple attention span was poor.
3) He had difficulty acquiring and retaining new structured verbal information (i.e., stories)
4) His visual recognition memory was below expectations
5) He demonstrated word-finding difficulty
6) He had trouble on a measure of mental calculation ability
7) Although some answers on health and safety were appropriate, others were incomplete and/or incorrect.
8) The patient demonstrated a number of cognitive difficulties
9) In sum, the findings suggest deficient learning and variability in memory
This report had the effect of muddying the waters of my getting DBS surgery. Given the significant and proven benefits of DBS for patients such as myself, the report created delay and therefore was counterproductive. The Doctor had unleashed havoc on the decision-making process without any attempt to validate or explain her findings.
First, I’m not sure why a neuropsychologist would comment on my knowledge of healthcare, or why it is relevant.
I’m also baffled by her reference to a hemangioma. I have no explanation for that statement or where she got it.
The second area of concern was the stipulation that I had a word-finding difficulty. I play a game of Scrabble almost once a day and I am ranked as a top 5% player by a popular online game site. I recently beat the Grand Master three games in a row, which is hard for anyone to do, and impossible to achieve by someone with “a number of cognitive difficulties”, as the Doctor had found.
Third, my activities and accomplishments since the test quite simply are not consonant with the findings of the neuropsychologist. In particular, a company, in which I have known the Chairman and the CEO for decades, had filed a pre-packaged plan for restructuring the company in bankruptcy. This approach was out of character for these gentlemen so I looked into the matter.
Unfortunately, the cat was out of the bag and little could be done to unravel the approach in the bankruptcy proceeding at such a late date in the process. After reading of thousands of pages of legal briefs, I developed and executed a series of complex legal strategies (even though I am not a lawyer). I filed 16 pleadings in the Bankruptcy Court, the Department of Justice, the Securities and Exchange Commission and the FCC, and I appeared before the Judge in the Court hearing and met with government agency personnel to explain my findings.
Given the circumstances, my strategy focused on getting relief through the FCC.
This outcome would be very difficult for any person to achieve and impossible for a person with cognitive difficulties to even be taken seriously.
I believe that it is safe to say that most people would not even understand the nuances of the approaches that I used with each agency.
My fourth critique of the assessment was precipitated by the feedback of a business partner. He stopped me after my reading two of the report’s conclusions, asked to clarify the objective of the report, and then offered that I had disproved the very first conclusion in my wok of the prior week.
At this point, I had a Registered Nurse conduct a confidential survey of my current acquaintances which was designed to ascertain their feedback regarding my cognitive conditions.
At this point, I had a Registered Nurse conduct a confidential survey of my current acquaintances which was designed to ascertain their feedback regarding the following cognitive conditions:
Ability to multitask
Retaining new information
Visual recognition memory
Mental calculation ability
Difficulties with cognitive issues such as memory
The neuropsychologist had rated each of the above attributes as “below average”. In contrast, the people who deal with me on a regular basis have a very different perspective. That is, 90% of their ratings were higher than the Doctor’s and every person found my ability to synthesize new information and my ability to perform mental calculations to be “above average”.
Taken together, the proficiency in Scrabble, the activities in the bankruptcy proceeding, and the survey of close acquaintances paint a bleak picture for using neuropsychological testing as a tool for DBS qualification.
The findings in this case also raise a broader question. How could the assessment be so wrong about my cognitive abilities?
My belief is that neuropsychological assessments are highly judgmental and heavily influenced by preconceived notions. In my case, 20 -years of Parkinson’s disease and subdural hematomas set the stage for a poor assessment. On my side, I was bored and tuned out early in the session given that I perceived it to be four hours of annoying trivia designed for an eighth grader.
As explained by Chad D. Vickery, et al. in an article in Science Direct:
“…it has been pointed out that neuropsychological tests may be “failed” for a variety of reasons apart from neurological disease, including psychiatric conditions such as depression or anxiety, inattentiveness secondary to various causes, and limited cooperation or poor motivation. Therefore, prior to inferring brain dysfunction on the basis of neuropsychological test results, alternative explanations must be carefully considered and ruled out.” (Emphasis added)
Along those lines, I believe that several conclusions and recommendations can be drawn from this case study. First, doctors and patients should not take the findings of a neuropsychological assessment at face value. Second, in cases of a poor showing, the standard practice should include getting a second, blind opinion. Third, the people doing the assessment should not review the patient’s medical history before the assessment. Fourth, the people doing the evaluation should interview the patient’s family and/or friends after administrating the test to collaborate the findings. Fifth, the study should be limited to two hours. If there is some ambiguity, a second two-hour assessment should occur on another day.
Essentially, these five steps provide a roadmap for considering “alternative explanations” for poor showings.
Given that my neurologist was effectively blocking DBS surgery, I agreed to a second neuropsychology test. This test covered 14 hours over several days. The conclusion was:
“Therefore, based on the clinical interview, behavioral observations, and test results, Mr. Zecola appears to be a good candidate for the DBS procedure from a neuropsychological perspective at this time”.
Patients being tested for cognitive issues generally cannot defend themselves against errant neuropsychological assessments. Therefore, the above recommendations should be adopted by the industry associations in order for the practice to serve as a legitimate gatekeeper to healthcare treatments.
Ali Harati and Thomas Müller in an article in Surgical Neurology International summarize the issue as follows:
STN DBS in the treatment of PD has resulted in a significant reduction of motor symptoms and improved independence and quality of life in appropriately selected patients. However, it may have isolatable effects on verbal fluency and related function. Case series in the literature reported similar findings. Potential candidates for DBS should be counseled about the risk of mild cognitive declines.
From a patient’s vantage point, conditions such as responsiveness to levodopa and the presence of dyskinesia indicate potential significant benefits from DBS. The risk of mild cognitive declines does not compare in scope to these benefits. Moreover, the declines are likely to occur even without DBS.
The FDA’s standard review process covers a wide range of practices, including approving the veracity of genetic tests. Why hasn’t the FDA reviewed the standard industry practice of interjecting neuropsychological testing into the decision-making process for DBS? In the absence of FDA approval, neurologists should not be using these neuropsychological assessments for a no/no go decision on DBS (or any other condition); any more than prescribing cannabis for the recovery from DBS surgery without any verifiable evidence of the risks and rewards.