Hand function in relation to brain lesions and corticomotor‐projection pattern in children with unilateral cerebral palsy

Abstract

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...

Motor imagery ability in children with congenital hemiplegia: Effect of lesion side and functional level

“…Children with corticomotor projections that have reorganised generally exhibit lower levels of hand function (Holmström, et al, 2009), which could potentially explain our finding that children with poorer function levels are less accurate at MOTOR IMAGERY IN CONGENITAL HEMIPLEGIA 18 performing a motor imagery task. The relationship could also be suggestive of a failure to properly develop internal representations of movement in children with low function levels as a result of their limitations in motor execution.…”

The role of transcranial magnetic stimulation in the characterization of congenital hemiparesis

“…As noted by the authors, stability of the GMFCS was higher in a recent study 2 compared with an earlier study. 3 Is it that clinicians and parents require some familiarization of these classification systems over time to enhance stability?…”

“…Holmströ m et al 2 report a further study on 16 children with congenital hemiparesis evaluated by TMS and magnetic resonance imaging as well as with a detailed assessment of both uni-and bimanual hand function. Several aspects of this study are relevant for both the clinician and the researcher dealing with congenital hemiparesis.…”

“…It is reliable, valid, and stable over time. 2,3 The MACS is a recently developed classification tool describing children's ability to handle objects in daily life. 4 There is some evidence for the reliability and validity of the MACS, however, the paper by Imms et al is the first to examine its stability, as well as adding to previous work on the stability of the GMFCS.…”

“…Further work examining the stability of the MACS in a wider range of age groups and over longer periods of time with more assessment points is required, as has been carried out with the GMFCS. 2 This of course begs the question, what is an appropriate length of time to examine 'stability' of a characteristic in question?…”