TMS Transcranial magnetic stimulation WMDI White-matter damage of immaturity AIM To investigate relationships between hand function, brain lesions, and corticomotor projections in children with unilateral cerebral palsy (CP).METHOD The study included 17 children (nine males, eight females; mean age 11.4 [SD 2.4] range 7-16y), with unilateral CP at Gross Motor Function Classification System level I and Manual Ability Classification System level I or II. Hand function was assessed with the Box and Blocks test and Assisting Hand Assessment (AHA). Conventional structural magnetic resonance images were assessed visually for type, location, and extent of brain lesions. Single-pulse transcranial magnetic stimulation (TMS) provided information on organization of corticomotor projections.
RESULTSThe most favourable hand function was seen in children who had white-matter damage of immaturity with mild white-matter loss and contralateral motor projections. Children with ipsilateral projections had the most impaired function. Nevertheless, in this subgroup a range of ability was seen (AHA 29-59%). Motor-projection patterns appeared to be influenced by lesion extent and location, but not by lesion type.
INTERPRETATION Combining information from structural magnetic resonance images and TMScan improve prediction of hand function. A wide variation in hand function was seen within all motor-projection patterns. Although the most impaired hand function was seen in the ipsilateral motor-projection group, some children in this group had fairly good ability. Such information is important for treatment planning.The availability of neuroimaging and neurophysiology techniques, in particular magnetic resonance imaging (MRI) and transcranial magnetic stimulation (TMS), has greatly improved our understanding of the neural correlates of cerebral palsy (CP).1-4 Previous research has mainly been focused on overall motor impairment and the associations with brain abnormalities. Detailed descriptions of hand function have rarely been the focus of existing studies. In the few studies in which hand motor function has been examined specifically, outcome is often classified into broad categories, such as mild, moderate, or severe, which are not sufficiently sensitive to the large variation in hand function that is observed in children with unilateral CP. 5 CP can be caused by a range of brain lesions, 1,6 and there is some evidence that the extent of a lesion is associated with the severity of overall impairment. For example, it has been shown that, in periventricular white-matter lesions, mild white-matter loss is often associated with a mild degree of overall motor impairment, whereas extensive white-matter loss leads to more severely impaired function. 7,8 Lesions that affect grey matter (cortex, thalamus or basal ganglia) have been reported to cause moderate to severe motor impairments.9,10 The few existing studies in which hand function in children with unilateral CP has been investigated also indicate that the extent of a lesion is related t...