  One of the most prevalent complaints of individuals with mid-stage and
advanced Parkinson's disease (PD) is the fluctuating response to their
medication (i.e., ON state with maximum benefit from medication and OFF state
with no benefit from medication). In order to address these motor fluctuations,
the patients go through periodic clinical examination where the treating
physician reviews the patients' self-report about duration in different
medication states and optimize therapy accordingly. Unfortunately, the
patients' self-report can be unreliable and suffer from recall bias. There is a
need to a technology-based system that can provide objective measures about the
duration in different medication states that can be used by the treating
physician to successfully adjust the therapy. In this paper, we developed a
medication state detection algorithm to detect medication states using two
wearable motion sensors. A series of significant features are extracted from
the motion data and used in a classifier that is based on a support vector
machine with fuzzy labeling. The developed algorithm is evaluated using a
dataset with 19 PD subjects and a total duration of 1,052.24 minutes (17.54
hours). The algorithm resulted in an average classification accuracy of 90.5%,
sensitivity of 94.2%, and specificity of 85.4%.
