Factors Associated with Lumbar Puncture Participation in Alzheimer's Disease Research

BACKGROUND

Cerebrospinal fluid (CSF) provides insight into the spectrum of Alzheimer's disease (AD) pathology. While lumbar punctures (LPs) for CSF collection are generally considered safe procedures, many participants remain hesitant to participate in research involving LPs.

OBJECTIVE

To explore factors associated with participant willingness to undergo a research LP at baseline and follow-up research study visit.

METHODS

We analyzed data from 700 participants with varying cognition (unimpaired, mild cognitive impairment, and dementia) in the Wisconsin Alzheimer's Disease Research Center. We evaluated the relationship of demographic variables (age, sex, race, ethnicity, and years of education) and clinical variables (waist-to-hip ratio, body mass index, AD parental history, cognitive diagnosis) on decision to undergo baseline LP1. We evaluated the relationship of prior LP1 experience (procedure success and adverse events) with the decision to undergo follow-up LP2. The strongest predictors were incorporated into regression models.

RESULTS

Over half of eligible participants opted into both baseline and follow-up LP. Participants who underwent LP1 had higher mean education than those who declined (p = 0.020). White participants were more likely to choose to undergo LP1 (p < 0.001); 33% of African American participants opted in compared to 65% of white participants. Controlling for age, education, and AD parental history, race was the only significant predictor for LP1 participation. Controlling for LP1 mild adverse events, successful LP1 predicted LP2 participation.

CONCLUSION

Race was the most important predictor of baseline LP participation, and successful prior LP was the most important predictor of follow-up LP participation.

The U-ARE Protocol: A Pragmatic Approach to Decisional Capacity Assessment for Clinical Research

With increased longevity and growth in the number of older adults comes rising rates of individuals with cognitive impairment and dementia. The expansion of this population has important implications for research on aging and dementia syndromes, namely increased enrollment of older individuals in clinical research. Ethical prerogatives, as well as historical underrepresentation of persons with dementia in research studies due to the perceived burden of traditional decisional capacity evaluations, necessitates the development of pragmatic approaches to ascertain decisional abilities in research settings. We outline a protocol used in the Wisconsin Alzheimer's Disease Research Center (ADRC) that adopts a stepped approach to the evaluation of decisional capacity meant to maximize study visit efficiency while preserving participant safety and autonomy. The protocol specifies the structure of the consent process and incorporates a brief semi-structured interview based on Appelbaum & Grisso's theoretical model for evaluating a patient's decisional capacity to provide informed consent to participate in research. This protocol is easily implemented in a research study visit and is designed to minimize participant burden and ensure reliable assessment of decisional capacity in older adults across a wide range of research protocols. The protocol emphasizes capacity optimization, using memory aids and other compensatory strategies to preserve participant autonomy while protecting welfare.