Introduction: The cause of idiopathic scoliosis remains unknown, although research has possibly eliminated some hypothetical causes.

The fact that many patients with idiopathic scoliosis appear to be out of balance, has led many researchers to postulate that a brain stem abnormality involving the vestibular system in the cause of this condition.

Material and Methods: Forty – five female patients 12 to 14 years old (mean age 13.5) with right thoracic idiopathic scoliosis (scoliotic curves:20°–40°, study group) and 31 non-scoliotic healthy subjects in the same age group (mean age=13.1, control group) were included in this study.

An electronystagmographic study of labyrinthine function with caloric stimulation was performed in all patients. The nystagmus was recorded with the electronystagmographic technique (ENG) using Hartmann device. The recordings were performed in a dark, silent room with the tested subject in the supine position and with it’s eyes closed.

We evaluated: the frequency, the amplitude and the slow phase velocity of nystagmus.

The differences in labyrinthine sensitivity were evaluated with the use of unilateral weakness parameter, while differences in left – and right – beating nystagmus evaluated by estimating the directional preponderance parameter.

Results: No one children of the study presented spontaneous or positional nystagmus.

Nineteen patients from the study group (44.2%), revealed unilateral weakness (difference between left and right labyrinth > 20%) of the left labyrinth.

Seventeen patients from the study group (39.5%) revealed directional preponderance of the right-beating nystagmus. These differences were statistical significant (p< 0.05, Chi-Square test). Seventeen patients from the study group revealed both left unilateral weakness and directional preponderance of the right labyrinth, while two patients revealed only left unilateral weakness. A significant correlation was found between the degree of the curvature and the percentage of unilateral weakness.

Conclusion: It is very difficult to draw any conclusions as to whether a vestibular imbalance may be a contributory factor to adolescent idiopathic scoliosis or whether the vestibular findings are secondary to the spine deformity.