| A new device, DynaWand was designed, fabricated, and programmed, to register grip force while simultaneously controlling a computer cursor. DynaWand was tested on 12 children with Cerebral Palsy (CP) ages 5--13 (mean = 7.3, Std = 2.3) and 18 age matched controls ages 5--11 (mean 8.2, Std = 1.9). The two tests administered were a Fitts tests and a Grip Precision test. The Fitts test was conducted using the DynaWand's imbedded accelerometer as a tilt sensor, capable of controlling a computer cursor. The results from the Fitts test were used to calculate the Psychomotor Delay (PMD) associated with the movement trials. The Grip Precision test used the DynaWand's Force Sensitive Resistors (FSRs) and accelerometer to measure the grip force to load force onset latency and grip force at load force onset. Results from the Fitts test show that PMD for the impaired arms of the CP group averaged 184 +/- 80ms and 165 +/- 11ms on day 1 and day 2 of testing, respectively. The unimpaired arms of that group averaged 132 +/- 108ms and 127 +/- 100ms. The average PMD value for the control group was 130 +/- 92ms. The grip-to-load force onset latency for the impaired and unimpaired arms of the CP group averaged 171 +/-114ms and 39 +/- 25ms, respectively. Controls averaged 45 +/- 45ms. The grip force at load force onset for the impaired and unimpaired arms of the CP group was 215 +/- 172 and 17 +/-16 relative force units, respectively. Controls averaged 57 +/- 76 relative force units. These results show the unimpaired arms of the CP group had similar PMD values to the control and these delays were shorter than the impaired arms. The grip-to-load force onset latency for the impaired arms of the CP group was substantially higher than the unimpaired arms and controls. This suggests the DynaWand may be capable of quantifying temporal and force-related aspects of coordination deficits in children with hemiparetic injuries. |
