Motor cortical hyperexcitability in idiopathic scoliosis: could focal dystonia be a subclinical etiological factor?


The aetiology of idiopathic scoliosis (IS) remains unknown; however, there is a growing body of evidence suggesting that the spine deformity could be the expression of a subclinical nervous system disorder. A defective sensory input or an anomalous sensorimotor integration may lead to an abnormal postural tone and therefore the development of a spine deformity. Inhibition of the motor cortico-cortical excitability is abnormal in dystonia. Therefore, the study of cortico-cortical inhibition may shed some insight into the dystonia hypothesis regarding the pathophysiology of IS. Paired pulse transcranial magnetic stimulation was used to study cortico-cortical inhibition and facilitation in nine adolescents with IS, five teenagers with congenital scoliosis (CS) and eight healthy age-matched controls. The effect of a previous conditioning stimulus (80% intensity of resting motor threshold) on the amplitude of the motor-evoked potential induced by the test stimulus (120% of resting motor threshold) was examined at various interstimulus intervals (ISIs) in both abductor pollicis brevis muscles. The results of healthy adolescents and those with CS showed a marked inhibitory effect of the conditioning stimulus on the response to the test stimulus at interstimulus intervals shorter than 6 ms. These findings do not differ from those reported for normal adults. However, children with IS revealed an abnormally reduced cortico-cortical inhibition at the short ISIs. Cortico-cortical inhibition was practically normal on the side of the scoliotic convexity while it was significantly reduced on the side of the scoliotic concavity. In conclusion, these findings support the hypothesis that a dystonic dysfunction underlies in IS. Asymmetrical cortical hyperexcitability may play an important role in the pathogenesis of IS and represents an objective neurophysiological finding that could be used clinically.

This is a preview of subscription content, access via your institution.

We’re sorry, something doesn't seem to be working properly.

Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.

Fig. 1
Fig. 2
Fig. 3


  1. 1.

    Sahlstrand T, Örtengren R, Nachemson A (1978) Postural equilibrium in adolescent idiopathic scoliosis. Acta Orthop Scand 49:54–65

    Google Scholar 

  2. 2.

    Herman R, Mixon J, Fisher A, Maulucci R, Stuyck J (1985) Idiopathic scoliosis and the central nervous system: a motor control problem. Spine 10:1–14

    Article  CAS  PubMed  Google Scholar 

  3. 3.

    Adler N, Bleck EE, Rinsky IA, Young W (1986) Balance reactions and eye hand coordination in idiopathic scoliosis. J Orthop Res 4:102–107

    Article  CAS  PubMed  Google Scholar 

  4. 4.

    Byl NN, Gray JM (1993) Complex balance reactions in different sensory conditions: adolescents with and without idiopathic scoliosis. J Orthop Res 11:215–227

    Article  CAS  PubMed  Google Scholar 

  5. 5.

    Lao MLM, Chow DHK, Guo X, Cheng JCY, Holmes AD (2008) Impaired dynamic balance in adolescent with idiopathic scoliosis and abnormal somatosensory evoked potential. J Pediatr Orthop 28:846–849

    PubMed  Google Scholar 

  6. 6.

    Barrack RL, Withecloud TS, Burke SW, Cook SD, Harding AS (1984) Propiocepcion in idiopathic scoliosis. Spine 9:681–685

    Article  CAS  PubMed  Google Scholar 

  7. 7.

    Cook SD, Harding Af, Burke SW, Whitecloud TS, Barrack RL, Leinhardt TM (1986) Upper extremity propioception in idiopathic scoliosis. Clin Orthop 213:118–124

    PubMed  Google Scholar 

  8. 8.

    Barrack RL, Wyatt MP, Whitecloud TS, Whitecloud TS, Barrack RL, Leinhardt TM (1988) Vibratory hipersensivity in idiopathic scoliosis. J Pediatr Orthop 8:389–395

    CAS  PubMed  Google Scholar 

  9. 9.

    Wyatt MP, Barrack RL, Mubarack SJ, Whitecloud TS, Burke SW (1986) Vibratory response in idiopathic scoliosis. J Bone Joint Surg 68B:714–718

    Google Scholar 

  10. 10.

    McInnes E, Hill DL, Raso VJ, Chetner B, Greenhill BJ, Moreau MJ (1991) Vibratory response in adolescents who have idiopathic scoliosis. J Bone Joint Surg 73A:1208–1212

    Google Scholar 

  11. 11.

    Pincott JR, Taffs LF (1982) Experimental scoliosis in primates. J Bone Joint Surg 64B:503–507

    Google Scholar 

  12. 12.

    Barrios C, Tunon MT, De Salis JA, Beguiristain JL, Cañadell J (1987) Scoliosis induced by medullary damage: an experimental study in rabbits. Spine 12:433–439

    Article  CAS  PubMed  Google Scholar 

  13. 13.

    Pincott JR, Davies JS, Taffs LF (1984) Scoliosis caused by section of dorsal spinal nerve roots. J Bone Joint Surg 66B:27–29

    Google Scholar 

  14. 14.

    Suk SI, Song HS, Lee CK (1988) Scoliosis induced by anterior and posterior rhizotomy. Spine 14:692–697

    Article  Google Scholar 

  15. 15.

    Barrios C, Arrotegui JI (1992) Experimental kyphoescoliosis induced in rats by selective brain stem damage. Int Orthop 16:146–151

    Article  CAS  PubMed  Google Scholar 

  16. 16.

    Hallett M (1995) Is dystonia a sensory disorder? Ann Neurol 38:139–140 (Editorial)

    Article  CAS  PubMed  Google Scholar 

  17. 17.

    Abbruzzese G, Berardelli A (2003) Sensorimotor integration in movement disorders. Mov Disord 18:231–240

    Article  PubMed  Google Scholar 

  18. 18.

    Kobayashi M, Pascual-Leone A (2003) Transcranial magnetic stimulation in neurology. The Lancet neurol 2:145–156

    Article  Google Scholar 

  19. 19.

    Rothwell JC, Thompson PD, Day BL, Boyd S, Marsden CD (1991) Stimulation of the human motor cortex through the scalp. Exp Physiol 76:159–200

    CAS  PubMed  Google Scholar 

  20. 20.

    Kujirai T, Caramia MD, Rothwell JC, Day BL, Thompson PD, Ferbert A, Wroe S, Asselman P, Marsden CD (1993) Cortico cortical inhibition in human motor cortex. J Physiol 471:501–519

    CAS  PubMed  Google Scholar 

  21. 21.

    Ziemann U, Rothwell JC, Ridding MC (1996) Interactions between intracortical inhibition and facilitation in human motor cortex. J Physiol 496:873–881

    CAS  PubMed  Google Scholar 

  22. 22.

    Ridding MC, Sheean G, Rothwell JC, Inzelberg R, Kujiray T, Inzelberg R, Kujiray T (1995) Changes in the balance between motor cortical excitation and inhibition in focal task specific dystonia. J Neurol Neurosurg Psych 59:493–498

    Article  CAS  Google Scholar 

  23. 23.

    Mavroudakis N, Caroyer JM, Brunko E, Zegers de Beyl D (1995) Abnormal motor evoked responses to transcranial magnetic stimulation in focal dystonia. Neurology 45:1671–1677

    CAS  PubMed  Google Scholar 

  24. 24.

    Ikoma K, Samii A, Mercuri B, Wassermann EM, Hallett M (1996) Abnormal cortical motor excitability in dystonia. Neurology 46:1371–1376

    CAS  PubMed  Google Scholar 

  25. 25.

    Siebner HR, Tormos JM, Ceballos-Baumann AO, Auer C, Catala MD, Conrad B, Pascual-Leone A (1999) Low-frequency repetitive transcranial magnetic stimulation of the motor cortex in writer’s cramp. Neurology 52:529–537

    CAS  PubMed  Google Scholar 

  26. 26.

    Winter RB (1995) Congenital spinal deformity. In: Lonstein JE, Bradford DS, Winter RB, Ogilvie JW (eds) Moe′s textbook of scoliosis and other spinal deformities. WB Saunders, Philadelphia

    Google Scholar 

  27. 27.

    Uitenbroek DG (1997) SISA-Binomial. Accessed 1 June 2008

  28. 28.

    Yamada H, Yamamoto H, Ikada T et al (1971) A neurological approach to the etiology and therapy of scoliosis. J Bone Joint Surg 53A:197–198

    Google Scholar 

  29. 29.

    Yamada K, Yamamoyo H, Nakagawa Y, Tezuka A, Tamura T, Kawata S (1984) Etiology of idiopathic scoliosis. Clin Orthop 184:50–57

    PubMed  Google Scholar 

  30. 30.

    Brinker MR, Willis JK, Cook SD, Whitecloud TS, Bennett JT, Barrck RL, Ellman MG (1992) Neurologic testing with somatosensory evoked potentials in idiopathic scoliosis. Spine 17:277–279

    Article  CAS  PubMed  Google Scholar 

  31. 31.

    Fernández-Bermejo E, García-Jimenez MA, Fernandez-Palomeque C, Munuera L (1993) Adolescent idiopathic scoliosis and joint laxity. Spine 18:918–922

    Article  PubMed  Google Scholar 

  32. 32.

    Goldberg CJ, Dowling FE, Fogarty EE, Moore DP (1995) Adolescent idiopathic scoliosis and cerebral asymmetry: an examination of a nonspinal perceptual system. Spine 20:1685–1691

    CAS  PubMed  Article  Google Scholar 

  33. 33.

    Machida M, Dubousset J, Imamura Y, Iwaya T, Yamada T, Kimura J, Toriyama S (1994) Pathogenesis of idiophatic scoliosis: SEPs in chicken with experimentally induced scoliosis and in patients with idiopathic scoliosis. J Pediatr Orthop 14:329–335

    CAS  PubMed  Google Scholar 

  34. 34.

    Tinazzi M, Rosso T, Fiaschi A (2003) Role of the somatosensory system in primary dystonia. Mov Disord 18:605–622

    Article  PubMed  Google Scholar 

  35. 35.

    Hallet M (1998) The neurophysiology of dystonia. Arch Neurol 55:601–603

    Article  Google Scholar 

  36. 36.

    Berardelli A, Rothwell JC, Hallett M, Thompson PD, Manfredi M, Marsden CD (1998) The pathophysiology of primary dystonia. Brain 121:1195–1212

    Article  PubMed  Google Scholar 

  37. 37.

    Jankovic J, Leder S, Warner D, Schwartz K (1991) Cervical dystonia: clinical findings and associated movement disorders. Neurology 41:1088–1091

    CAS  PubMed  Google Scholar 

  38. 38.

    Defazio G, Abbruzzese G, Girlanda P, Buccafusca M, Curra A, Marchese R, Martino D, Masi G, Mazzella L, Vacca L, Livrea P, Berardelli A (2003) Primary cervical dystonia and scoliosis: a multicenter case-control study. Neurology 60:1012–1015

    CAS  PubMed  Google Scholar 

  39. 39.

    Duane DD (1998) Familiar cervical dystonia, head tremor and scoliosis: a case report. Adv Neurol 78:117–120

    CAS  PubMed  Google Scholar 

  40. 40.

    Furukawa Y, Kish SJ, Lang AE (2000) Scoliosis in a Dopa responsive dystonia family with mutation of of the GTP cyclohydrolase I gene. Neurology 54:2187

    CAS  PubMed  Google Scholar 

  41. 41.

    Micheli F, Pardal MF, Gatto E, Paradiso G (1991) Dopa responsive dystonia masquerading as idiopathic kyphoscoliosis. Clin Neuropharmacol 14:367–371

    CAS  PubMed  Google Scholar 

  42. 42.

    Narayan RK, Loubser PG, Jankovic J, Donovan WH, Bontke CF (1991) Intrathecal baclofen for intractable axial dystonia. Neurology 41:1141–1142

    CAS  PubMed  Google Scholar 

  43. 43.

    Berardelli A, Rona S, Inghilleri M, Manfredi M (1996) Cortical inhibition in Parkinson’s disease: a study with paired magnetic stimulation. Brain 119:71–77

    Article  PubMed  Google Scholar 

  44. 44.

    Ridding MC, Inzelberg R, Rothwell JC (1995) Changes in excitability of motor cortical circuitry in patients with Parkinson disease. Ann Neurol 37:181–188

    Article  CAS  PubMed  Google Scholar 

  45. 45.

    Duvoisin RC, Marsden CD (1975) Note in the scoliosis of Parkinsonism. J Neurol Neurosurg Psychiatr 38:787–793

    Article  CAS  PubMed  Google Scholar 

  46. 46.

    Baik JS, Kim JS, Park HP, Han SW, Park JH, Lee MS (2009) Scoliosis in patients with Parkinson’s disease. J Clin Neurol 5:91–94

    Article  PubMed  Google Scholar 

  47. 47.

    Grimes JD, Hassan MN, Trent G, Halle D, Armstrong G (1986) Clinical and radiographic features of scoliosis in Parkinson disease. Adv Neurol 45:353–355

    Google Scholar 

  48. 48.

    Cahn S, Herzog AG, Pascual-Leone A (2003) Paired-pulse transcranial magnetic stimulation: effects of hemispheric laterality, gender, and handedness in normal controls. J Clin Neurophys 20:371–374

    Article  Google Scholar 

  49. 49.

    Takeuchi N, Chuma T, Ikoma Y, Matsuo Y, Mano Y (2005) The intracortical inhibition on the motor cortex contralateral to normal hands in patients with dystonia: a study using paired transcranial magnetic stimulation. Int Congress Series 1278:257–259

    Article  Google Scholar 

  50. 50.

    Chen R, Tam A, Butefisch C, Corwell B, Ziemann U, Rothwell JC, Cohen LG (1998) Intracortical inhibition and facilitation in different representation of the human motor cortex. J Neurophysiol 80:2870–2881

    CAS  PubMed  Google Scholar 

  51. 51.

    Kimiskidis VK, Potoupnis M, Papagiannopoulos SK, Dimopoulos G, Kazis DA, Markou K, Zara F, Kapetanos G, Kazis AD (2007) Idiopathic scoliosis: a transcranial magnetic stimulation study. J Muskuloskelet Neuronal Interact 7:155–160

    CAS  Google Scholar 

  52. 52.

    Ziemann U, Lonecker S, Steihoff BJ, Paulus W (1996) Effects of antiepileptic drugs on motor cortex excitability: a transcranial magnetic stimulation study. Ann Neurol 40:367–378

    Article  CAS  PubMed  Google Scholar 

  53. 53.

    Fuhr P, Agostino R, Hallett M (1991) Spinal motor neuron excitability during the silent period after transcranial brain stimulation. Electroencephalogr Clin Neurophysiol 81:257–262

    Article  CAS  PubMed  Google Scholar 

  54. 54.

    Inghilleri A, Beradelli A, Marchetti P, Manfredi M (1996) Effects of diazepam, baclofen and thiopental on the silent period evoked by transcranial magnetic stimulation in humans. Exp Brain Res 109:467–472

    Article  CAS  PubMed  Google Scholar 

  55. 55.

    Mavroudakis N, Caroyer JM, Brunko E, Zegers de Beyl D (1995) Abnormal motor evoked responses to transcranial magnetic stimulation in focal dystonia. Neurology 45:1671–1677

    CAS  PubMed  Google Scholar 

  56. 56.

    Rona S, Berardelli A, Vacca L, Inghilleri M, Manfredi M (1998) Alterations of motor cortical inhibition in patients with dystonia. Mov Disord 13:118–124

    Article  CAS  PubMed  Google Scholar 

  57. 57.

    Stinear CM, Byblow WD (2005) Task dependent modulation of silent period duration in focal hand dystonia. Mov Disord 20:1143–1151

    Article  PubMed  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Julio Doménech.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Doménech, J., Tormos, J.M., Barrios, C. et al. Motor cortical hyperexcitability in idiopathic scoliosis: could focal dystonia be a subclinical etiological factor?. Eur Spine J 19, 223–230 (2010).

Download citation


  • Adolescent idiopathic scoliosis
  • Dystonia
  • Cortico-cortical inhibition
  • Cortical hyperexcitability
  • Transcranial magnetic stimulation