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Postural stability is considered to become mature at the age of 15 [1]. It depends on the maturing process of the somatosensory, visual and vestibular organs. Static and dynamic posturography is used to measure the efficiency of balance control. Freyss's stabilometry, apart from the analysis of velocity and amplitude of the body sway, can offer the additional measurement: head velocity. It is helpful in confirming the somatosensory pathology disturbing balance system [2]. In this paper, Freyss's stabilometry was used in children with otitis media with effusion because of its dynamic construction and a great number of parameters easily compared with normal values.

The goal of the study was to estimate the balance control in children suffering from otitis media with effusion before operation.

Twenty-five children, aged 6–13 (average age: 9.2), with otitis media with effusion were tested using stabilometry. Stabilometry was made before the adenotomiam and/or ventilation tube insertion. In every case effusion was found in both ears on the basis of otoscopy and tympanometry. The hypoacusis was symmetrical and conductive, of the mean value: 24.2 dB (according to Fletcher). The control group consisted of 20 normal subjects aged 6–14 (average 9.6).

Freyss's stabilometer was used to test the balance disorders. It is composed of a movable platform and the head detector to measure the head velocity, apart from platform parameters. The platform was able to move forward–backward and to the sides according to the position of the body. The test lasted 80 s: 20 s for each sequence. Firstly the platform was moved forward–backward, then to the sides, with eyes open, then closed. Freyss's stabilometer was able to appreciate the following parameters: maximal and mean amplitude, mean velocity of the platform and mean velocity of the head. Every value is presented as a part of a hypothetical "1" which means the normal level of reactivity. The statistical Student's t-test was used to compare the obtained results.

The results obtained during stabilometry are presented in Table 1.

The comparison between normal subjects and the children with otitis media with effusion revealed the statistical differences only on the basis of one parameter: maximal amplitude of the platform. The data differed from each other when the platform was moved backward–forward and to the sides: in the first case with eyes closed, in the last with eyes open. So, the visual input did not modulate the balance control. Generally, maximal amplitude was higher during the movement to the sides both with eyes open and closed, both in normal and sick children. But it may be the general tendency to exhibit worse control of balance to the sides than forward–backward.

Casselbrandt reported that in young cases suffering from otitis media sway was greater, and its improvement could be observed, after insertion of tympanostomy tubes [3]. In our patients tested before operation (adenotomy and/or myringotomy with ventilation tube insertion), velocity of the platform was not significantly different from normal subjects. The only pathological finding was greater maximal amplitude of the platform sway. It may be the result of worse sensitivity of the dynamic posturography compared with the static one as it was observed by di Fabio [4] in peripheral vestibular disorders. But from the other side, it must be taken into consideration that balance disorders were not often met in otitis media secretoria by other authors. Zhang and Zhao [5] noted pathological posturography following the pathological peripheral ENG findings in about 20% of children. Koyuncu et al. [6] on otitis media with effusion, reported only 33% of vestibular disfunction, demonstrated both during ENG and Romberg's test.

It is very interesting that the imbalance syndrome is a sensitive factor of posttraumatic syndrome in children with subjective, non-specific complaints [7]. It suggests instability of fuctional construction of the central balance system in young child. It may be the result of age-related coordination between body equilibrium and visual input [8, 9]. Sologubov et al. [10] demonstrated that in healthy young people visual input is the most important element of balance control. Indeed, we noted worse, but not statistically important, balance control in those sequences of the equilibrium test when the eyes were kept closed both in normal and sick children. Casselbrandt et al. [3], on the basis of sway velocity measurement during posturography, concluded that when the tests were more difficult (for example without fixation) the results were worse in children less than 7 years of age. But it was unexpected that after anaesthesia (premedication) in very young children (aged average 6.9 years old) visual input was not able to improve disturbed balance control [11]. Unmatured vision, together with undeveloped vestibular function, may be responsible for such data. Our observation thoroughout our material of slightly worse balance control was previously discussed by Khramtsov [12]. He suggested the influence of the load weights to the lateral sway in children from early to late childhood.

Generally, especially in children, it is better to join the posturography with oculomotor testing for precise analysis of vestibular function. Stabilometry alone may be proposed as a screening test.

1. Otitis media with effusion may affect balance control detected by Freyss's stabilometry.
2. On the basis of this method, only one parameter was pathological: maximal amplitude of the platform sway.
3. When amplitude was too great, it was independent of visual control.
4. Taking into consideration that Freyss's stabilometry offers much more data which remain normal (comparing with healthy subjects), one can conclude that postural control seems to be barely disturbed in otitis media with effusion in children.