Working group 2: Behavioral biomarkers
Measuring the effect of a treatment on hyperphagia within the limited time-frame of a clinical trial has proven to be challenging. Body mass index (BMI), DEXA and weight can be useful proxy measures in overweight or obese patients who are hyperphagic. They are, however, less relevant for patients whose weight is maintained under external control or for patients who are at an earlier stage of the disease (pre-hyperphagic stage). In addition, these measures do not capture food-seeking abnormalities characteristics of individuals with PWS such as food sneaking and theft, foraging through the trash for food, getting up at night for food seek and eating unpalatable items (Dykens 2000). The hyperphagia questionnaire developed by Dykens and al (2007) addresses some of these issues and provides a quantifiable outcome measure for hyperphagia. It is currently the most used outcome measure in clinical trials for hyperphagia in PWS. It does not, however, capture the full spectrum of behavioral characteristics of PWS patients such as anxiety and other behaviors.
The overall goal is to develop new questionnaires and tools adapted to age and nutritional phases to better capture and measure the range of behaviors associated with behaviors around food. These instruments will serve two aims:
Develop tools to better understand the natural history of hyperphagia in PWS. This entails examining how these behaviors evolve over time and if there are some characteristics that correlate with age and/or nutritional phases described by Miller and collaborators.
Develop and validate tools to measure efficacy of a treatment against hyperphagia in a clinical trial setting. Tools will be developed for different categories of PWS patients, i.e., infants and young children at the pre-hyperphagic stage and children and adults at the hyperphagic stage who are obese or whose weight is under control.