A recently published study in Functional Neurology suggests that using data from an FDA-cleared watch-like device called the Personal KinetiGraph (PKG) provides an objective and more effective approach to assessing motor fluctuations in patients with Parkinson's disease (PD) compared with patient-reported motor diaries.
“Motor fluctuations, including 'wearing-off' and dyskinesia, are associated with increased disease severity and disability, and PD patients experience decreased quality of life as their response to medical therapy becomes less predictable,” said Echo Tan, MD, a neurologist at Cedars-Sinai Medical Center and lead author on the publication. “Effectively managing motor fluctuations is complicated by the lack of objective assessment tools, leading patients and physicians to rely on direct observation in the clinic or patient reports, which may be unrevealing, incomplete and unreliable. The results of our study demonstrate that the fluctuation score calculated by the PKG system provides objective quantification of motor fluctuations."
This may help improve the routine management of Parkinson's patients and enable more objective assessments in clinical trials of Parkinson's therapies, she said.
Tan told MD+DI the study revealed that the PKG system (developed by Global Kinetics) and the algorithms for calculating a fluctuator score can differentiate between non-dyskinetic and dyskinetic patients. The fluctuator score does not, however, have the sensitivity to detect mild wearing off because no prior study divided patients into more than a binary system. On the plus side, Tan said the PKG also can distinguish between exercise and dyskinesia on the graphical data obtained.
The fact that the fluctuator score was not sensitive enough to detect mild wearing off did come as a surprise to the investigators, but the fluctuator score did show progressively increasing average score range between the four groups, Tan said.
During a BIOMEDevice Boston 2019 panel discussion, Teresa Prego, vice president of marketing and marketing development at the Melbourne, Australia-based company, said the integration of consumer wearables with wearables for chronic disease management has changed the delivery of care and where that care is delivered.
"If I look at the PKG-Watch, for example, in Australia where there are great geographic distances between people with Parkinson's and a care provider. They are using this remotely," Prego said. "So you'll go and see your clinician, have an assessment, but then for the next year, there's really no need to go into the clinic. You can make care decisions remotely. They're wearing the vehicles to get that information to the clinician."
"This implies that it is better at detecting moderate to severe fluctuations," she said.
Most importantly, the device has changed the way Tan and her colleagues assess and monitor patients with Parkinson's disease.
"The PKG system can provide additional information about fluctuations that a clinic visit and history can not reveal," she said. "This is particularly useful for those patients who are not able to provide a good history – such as those with a language barrier or cognitive impairment. It can show true objective levodopa responsiveness, motor fluctuations, daytime somnolence, and medication compliance. "It can be an important triage mechanism for a referral to a movement disorder specialist, or for an advanced surgical therapy referral. It has provided another objective source of information for our clinicians in deciding how to change medical management. Patients also report that the medication reminder function on the device helps them with medication compliance, thereby also enhancing their motor function as well."
Parkinson’s disease patients typically respond well to medical therapy in the first few years of their disease, but about 40% of the patient population develops fluctuations of response to levodopa and dyskinesia after four to six years of treatment. That percentage jumps to 70% after long-term treatment of nine years or more, according to Global Kinetics. The company said it developed the PKG system to address the lack of objective measurement tools for movement disorders and quantifies the kinematics of Parkinson's symptoms, including tremor, bradykinesia, and dyskinesia. An algorithm translates the raw data from these assessments into a fluctuation score that can distinguish between patients with motor fluctuations and those without.
The study investigators correlated PKG fluctuator scores (FS) with clinical motor fluctuator profiles in a case-controlled cohort of the study that included 60 patients attending the Movement Disorders Clinic at Cedars-Sinai Medical Center in Los Angeles, CA. Of the 60 patients in the study, six had incomplete data and were excluded from analyses, the company noted.
Here are some key findings from the 54 subjects who completed a six-day PKG trial and completed a standardized motor diary:
- Based on Wearing Off Questionnaire (WOQ9) and Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part IV scores patients were categorized based on the presence and extent of fluctuations, as follows:
- Non-fluctuators (NF), N = 14
- Early fluctuators (EF), N = 15
- Moderate fluctuators (MF), N = 15
- Troublesome fluctuators (TF), N = 10
- The groups varied significantly in terms of disease duration, which was progressively longer with increasing severity of clinical fluctuation and PD dopamine medication measured as levodopa equivalent dose (LED).
- LED was more than double in patients with troublesome fluctuations compared to those without fluctuations, while patients in the groups including early and moderate fluctuators reported equivalent daily dosages.
- MDS-UPDRS score increased significantly with the severity of fluctuations, with the highest scores recorded in those with troublesome fluctuations.
- Patients had a higher tendency to return the PKG than the motor diary (88% vs. 65%).
- 50% of the patients in the troublesome fluctuator group were excluded due to incorrect diary completion.
- Compliance with the motor diary improved with decreasing severity of fluctuations.
- PKG fluctuation score significantly differentiated EF and TF (p = 0.01), as well as dyskinetic and non-dyskinetic subjects (p < 0.005). In contrast, motor diaries could not distinguish the four study groups on the basis of average OFF time, while average time with dyskinesia distinguished NF and MF but did not distinguish among all four groups.
- PKG identified high levels of dyskinesia in patients who denied having dyskinesia.
The study authors conclude that the data support the use of the PKG fluctuation score as an objective tool for capturing and quantifying motor fluctuations as a mechanism for triaging PD patients. They also note that the PKG transcends language and cognitive barriers and time constraints in the clinic, which are challenges to obtaining accurate patient symptoms to effectively adjust PD treatment.
The main barrier to adoption for products like these is reimbursement, Prego noted.
"Capturing this data and utilizing the advent of these consumer technologies to help manage chronic disease, it's pretty interesting," she said. "I think that our traditional ways of reimbursing for medical care have not quite caught up to where the development of consumer wearables has taken us."