Stay-FIT Pilot Study: Accelerometry is a good way to measure daily physical activity in adolescents with Cerebral Palsy.
Why did we do this study?
Cerebral palsy (CP) is a condition which involves difficulties with movement. As a result, all youth with CP, regardless of their functional ability, are at particular risk for inactivity. Different levels of self-mobility at home, at school and in the community in adolescents with CP can be categorized with the Gross Motor Function Classification System (GMFCS- E&R). Youth classified as GMFCS level I walk at home, school, outdoors, and in the community, while those classified as GMFCS level V are transported in a manual wheelchair in all settings.
Despite the growing interest in physical activity in youth with CP, there remains a gap in our knowledge on assessment of daily physical activity at home, at school, and in the community in adolescents with CP, particularly for those with more severe functional limitations (GMFCS Levels III-V).
The purpose of this study (a Stay-FIT pilot study) was to test the ability of a device known as an accelerometer to measure physical activity in adolescents with CP. Once the data was collected, we could determine the amount of time spent performing at various activity intensities. We are particularly interested in the amount of time youth do activities that makes them sweat and breathe hard (so called Moderate to Vigorous Physical Activity or MVPA).
What did we do?
Throughout late 2009 till December 2010, we asked twenty three adolescents with CP (n = 9 Level I, n = 5 Level II, n = 5 Level III, n = 4 Level IV) to wear two accelerometers for seven days. The devices were worn on both waist and wrist and put on when the child awoke. They were removed only when the participant went back to sleep or if the accelerometer would have been exposed to water.
Throughout the seven days, we asked the participants to record the time and reason for removal whenever the accelerometer was removed. These logs were used to remove the data from the times when the instruments were not worn.
What did we find?
The accelerometer was very well received by all participants. The only complaint received was that the device was visible and made classmates curious. However, only one adolescent refused to participate for this reason. All others had no negative experiences with the accelerometer. As a result, we can say that the device is a good instrument for gathering information about daily activity in adolescents.
When analyzed by percentage of wear time, the average amount Moderate-to-Vigorous Physical Activity (MVPA) accounted for only 4.5% of the total wear time. That means that on average, the people in the study spent approximately 9-10 hours sitting still and only 30 minutes of MVPA per day. We also found that one's GMFCS level is highly related to the amount of MVPA received. In other words the higher the GMFCS level the lower the MVPA.
What does this mean?
The findings of this study confirm that most young people with CP have physical activity levels less than 60 minutes of MVPA per day. We now know that the average of all study participants was half of that time. This is cause for concern. A highly sedentary lifestyle (low levels of activity) can bring an increased risk for the development of other health concerns such as cardiovascular disease later in life. We are currently studying vessel health in adults 20-40 years of age.
Did anything stand out?
Yes! Those children and adolescents with the best functional abilities (GMFCS Levels I & II) showed a greater variation of activity performance. This means that some of them were very active and some were very inactive. Thus we can say that although these children are able to perform more activity during the day, often they do not. In another study as part of the Stay-FIT research we have studied the reasons for this. We can begin to think about challenges within their personal life and environment that may lead to lower levels of physical activity.
Given the challenges that come with limitations in gross motor activities, it is not surprising that youth with GMFCS Levels III & IV showed a lower level of daily MVPA. Thus these adolescents are more limited in their ability to perform physical activity.
We believe the accelerometer is ready to use as a measure of habitual physical activity at home, at school, and in the community in adolescents with CP. We plan to use the accelerometer as an outcome measure in highly needed intervention studies that promotes youth to become and stay physically active.
We recommend to youth with CP: Do any activity that makes you sweat and breathe hard! You can read some tips and guidelines here.
For further information, please contact:
Dr. Jan Willem Gorter
This project is funded by the Ontario Federation for Cerebral Palsy. Investigators of this project are Jan Willem Gorter (PI), Brian Timmons, Maureen MacDonald, Robert Palisano, Peter Rosenbaum, and Virginia Wright.
Gorter JW, Noorduyn SG, Obeid J, Timmons BW (2012). Accelerometry: a feasible method to quantify physical activity in ambulatory and nonambulatory adolescents with cerebral palsy. International journal of pediatrics. 2012:329284.