Abstract
Aims: The underlying cause of Idiopathic Scoliosis (IS) remains enigmatic. Recently, an increasing number of studies disclosed Central Nervous System (CNS) abnormalities and asymmetries sometimes involving the corticospinal tracts. The present study was designed to investigate the motor system of scoliotic patients with transcranial magnetic stimulation. Methods:21 female patients with right IS (mean age=12.7, scoliotic curves:20û–40û) and 20 normal subjects (mean age=13.8) entered the study. Recordings were made with surface electrodes from 1st dorsal interosseous and abductor hallucis muscles. Corticomotor threshold (LT, UT, MT) was deþned at rest in 1% steps using the method of Mills & Nithi. Central motor conduction time (CMCT) was calculated using the F-wave method. Silent period (SP) measurements were done using a standardized protocol at 130% MT stimulus intensity. Other parameters included cortex to muscle latencies, F- and M-wave latencies, UT-LT range, amplitude and area of MEPs. Electrophysiological data were correlated with several clinical characteristics including handedness, degrees of the scoliotic curve and the Pedriolet and Nash indexes. Normality of data distribution was tested using the Kolmogorov-Smirnov test and thereafter appropriate statistical tests were used. Results: In 14 patients lower limbs were also tested and it was found that asymmetry of facilitated Cx-M was 1.4±0.75ms in IS (vs 0.71±0.47 in controls, p=0.059). It correlated signiþcantly with Nash & Moe and Perdriole indexes (Spearmanñs r=0,554 and 0.575 respectively, p< 0.05) and showed a trend towards signiþcance with degrees of scoliotic curve (Pearsonñs r=0.531, p=0.062). Conclusions: There are no signiþcant asymmetries or pathological alterations in the motor system of patients with IS. However, an increased asymmetry of facilitated
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
