Validation Study Of A Digital Measuring Device For Central Hand Representation In Children With A Neonatal Brachial Plexus Palsy

Hand function is one of the most complex and sophisticated sensorimotor skills, controlled by the interplay of precise motor efferent and multisensory afferent stimuli. A coherent central representation of the hand is essential for performing hand movements in a changing environment. However, the hand representation in the brain consists of many modalities (visual, proprioceptive, anthropometric,...). The division between explicit (conscious) and implicit (unconscious) representation of the hand is accepted by a large group of researchers. The explicit representation of the hand is based partly on visual afferents, the implicit on all other afferent inputs. Impaired hand function in everyday use after injury may be due to aberrant hand representation. Previous research showed that children with neonatal brachial plexus injury have impaired implicit hand representation with respect to hand size. Despite the good reproducibility of test results reported in the literature, the measurement method is very cumbersome. In the current technological revolution, digitalisation of the device is the ideal solution to make the measurement method clinically applicable in daily practice. Therefore, a new prototype digital device has been developed to automate the measurement method. This prototype works on the same principle and has the same dimensions as previous studies. It includes digital storage and processing of the measurement results. This study investigates the reproducibility (inter- and intra-observer) of the digital prototype. The study will recruit children aged between 8 and 18 years with a neonatal brachial plexus injury. Doctors treating this patient group will explain the study during consultations and provide a flyer. Participation in the study means that the patient will be invited to the UZ Ghent Paediatric Rehabilitation Centre, where two different doctors will independently perform the measurement. Specifically, they will be asked to place their hand on a mat and the fingertips, knuckles and wrist will be marked on the device. A wooden board is then placed over the hand so that the hand is no longer visible. The subject is then asked to indicate the fingertips, knuckles and wrist in random order, again recorded on the device. The test takes 5 to a maximum of 10 minutes (depending on cooperation). This measurement is repeated a 6 times on each hand. Based on these measurements, the device calculates the average of each participant's perceived hand width and finger length. These values are compared with the actual hand width and finger length. This allows us to calculate a percentage of overestimation. Studies using such data have already been published. The aim of this study is to measure the reproducibility (inter- and intraobserver) of the digitised version.