314 Abstracts/Résumés measurements were greater than 34 Âs. All 5 infants showed significant abnormalities in SSFEMG, suggestive of a probable neuromuscular transmission disorder. Jitter measurements ranged from 34.6 to 68.7 Âs. One infant was initially diagnosed with congenital myasthenic syndrome and even responded to treatment with pyridostigmine. Cytogenetic studies subsequently confirmed the diagnosis of PWS in all 5 cases. This is the first report of abnormal SSFEMG findings in infants with PWS. We suggest that these infants may have an abnormality in neuromus- cular junction transmission, contributing to their early hypotonia and inactivity, which improves with maturation. PWS should there- fore be considered in the differential diagnosis of hypotonic infants with neuromuscular junction abnormalities diagnosed by SSFEMG. http://dx.doi.org/10.1016/j.neucli.2013.10.003 3 Do diffusion tensor imaging parameters correlate with central motor conduction time in children with dystonia? V. McClelland b , D.E. Lumsden a , J. Ashmore c , G. Charles-Edwards c , K. Mills b , J.-P. Lin a a Complex Motor Disorders Service, Evelina Children’s Hospital, Guys and Saint-Thomas NHS Trust, London, United Kingdom b Department of Clinical Neurophysiology, King’s College Hospital, London, United Kingdom c Department of Neuroimaging, King’s College London, DeCrespingy Park, London, United Kingdom Introduction.— DTI is being used increasingly to investigate patients with movement disorders. Few studies have explored the relation- ship between DTI and electrophysiological parameters. Significant correlations between corticospinal tract (CST), fractional aniso- tropy (FA) and CMCT are seen in adults with Amyotrophic Lateral sclerosis. We aimed to determine whether DTI parameters correlate with CMCT in 49 children with dystonia. Methods.— Children (n = 49, age 3—19 years, median 9) with pai- red 32-direction Diffusion Weighted MRI (Achieva, Philips, 1.5 Tesla system) and CMCT measurements were studied. Distal motor and F-wave latencies were measured in the right ulnar nerve. Trans- cranial magnetic stimulation was applied over left motor cortex and motor evoked potentials were recorded in the activated right abductor digiti minimi. CMCT was calculated from the two latencies and classified as normal or prolonged. Tract Based Spatial statistics (TBSS) were used to explore group wise differences in Fractio- nal Anisotropy (FA), Mean Diffusivity (MD), Radial Diffusivity (RD) and Parallel Diffusivity (PD), comparing children with normal and abnormal CMCT. TBSS was also used to explore possible correlations between these measurements and CMCT. Additionally, regions of interest (ROI) were placed manually in the CST at the level of the pons, cerebral peduncle, posterior limb of internal capsule and cen- trum semiovale. DTI measurements extracted from these regions were compared as per the TBSS analysis. Results.— Neither TBSS nor ROI approaches demonstrated areas of significant difference in DTI parameters between children with nor- mal (n = 22) or abnormal (n =27) CMCT. Furthermore, no correlation was found between CMCT and any DTI parameter. Conclusion.— CMCT offers additional information over DTI when investigating children with motor disorders. We hypothesise that prolonged CMCT in individual children could reflect focal segments of CST disruption which are not spatially coincident, such that group-wise relationships in DTI parameters are not evident. Alterna- tively CMCT could be a more sensitive measure of CST dysfunction. http://dx.doi.org/10.1016/j.neucli.2013.10.004 4 Anatomical variation of the sural nerve K. Pugdahl , H. Tankisi , A. Fuglsang-Frederiksen Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark Background.— The sural nerve is commonly examined by nerve conductions studies (NCS) for the diagnosis of polyneuropathy (PNP). Anatomical variation of the sural nerve have been documen- ted in numerous cadaver studies and in a recent ultrasound study, however, neurophysiologists have generally not paid much attention to the anatomical variation, despite the possible influence on the sural NCS parameters. Methods.— Two hundred and forty patients referred on suspicion of PNP were prospectively examined. NCS confirmed a PNP in 122 patients, while PNP could not be shown in the remaining 118 patients. In 17 of these, the suspicion of an anatomical variation of the sural nerve was raised, as the sural NCS showed side-to- side variation, or the SNAP was absent or with disproportionately reduced amplitude compared to the neurologic examination. All 17 patients were examined with antidromic surface recordings as well as with orthodromic near-nerve needle technique. Results.— In 17 out of 118 patients (14.4%) in whom a PNP could not be proved with sensory and motor NCS, a suspected anato- mical variation of the sural nerve was confirmed. The anatomical variation was bilateral in 4 patients and unilateral in 13 patients (on the right side in 6 patients and on the left side in 7 patients). The most often seen variation was a distal type A formation with union of the medial sural cutaneous nerve (MSCN) and the peroneal communicating branch (PCB) at low calf. Discussion.— With this study, we aimed to emphasise that neuro- physiologists should be aware of different types of formations of the sural nerve which may cause misinterpretations of NCS. In case of sural SNAP amplitude of low amplitude in disproportion to the neurologic evaluation or to substantial side-to-side variation, the possibility of anatomical variation with distal union of MSCN and PCB at low calf should be considered. http://dx.doi.org/10.1016/j.neucli.2013.10.005 5 Assessment of functional impairment in patients following Oxplatin treatment S.B. Park , M. Davare , M. Koltzenburg UCL Institute of Neurology, London, United Kingdom Chemotherapy-induced peripheral neuropathy (CIPN) is a common and troubling condition associated with cancer treatment. Howe- ver, methods to assess the functional impact of CIPN on patients are lacking. Using a broad battery of assessments to evaluate hand func- tion (pegboard tasks, psychophysical tests), precision grip (grip-lift tasks), and neurophysiological parameters (nerve excitability and nerve conduction studies), 8 patients (mean age: 63.5 Â ± 2.1 years) were assessed 3.8 Â ± 2.1 months following completion of oxalipla- tin chemotherapy. A total of 88% patients reported some degree of neuropathic sensory symptoms at the time of follow-up. Patients demonstrated significantly elevated peak grip force (OX 14.9 ± 0.86N\HC 11.3 ± 0.47 N, P < .005) and static grip force (OX 12.9 ± 1.13 N\HC 9.3 ± 0.48 N, P < .05) compared to age appropriate healthy controls (n =5). Further, peak grip force was correlated with Purdue pegboard test results, so that patients with the most elevated peak grip force demonstrated the worst performance on the pegboard task (correlation coefficient = —.707\P < .01). Simi- larly, median sensory nerve action potential amplitude was also correlated with peak grip force (correlation coefficient = —.797,