Abstract
Congenital nystagmus (CN) is a clinical syndrome characterized by involuntary and rhythmical nystagmic eye movements that are found most often during the first weeks of life. The etiopathogenesis of congenital nystagmus has not been clear so far.
The disturbed detection of movement may be its cause. In etiology, there are considered metabolic abnormalities and structural anomalies of the CNS including the affection of optic pathways.
According to the form, congenital nystagmus is classified into basic categories by the shape of particular nystagmic jerks. The most frequent are jerk forms presented by biphasic nystagmic jerk with a rapid and slow phase, and pendular forms.
In jerky nystagmus, an abnormal development of oculo-motor brain areas controlling mechanisms of visual fixation are considered as its base. This type may display autosomal dominant, autosomal recessive and/or X-linked heredity.
The trial involved patients with congenital nystagmus examined at the ENT Clinic, Faculty Hospital Kralovske Vinohrady, for vertigo, hearing disturbances and tinnitus within 2001-2004. Totally, twelve patients were examined.
Detailed electromyographic or video-oculo-graphic examinations are needed for differentiating individual forms of congenital nystagmus. In our set, a sensoric defect or presence of ocular abnormality were observed in 4 cases, and the patients suffered from pendular form of CN.
The other patients-totally 8 - had motor CN, and 4 cases demonstrated pendular form, 4 cases jerk form of CN. Relatively high occurrence (5 cases - 42%) of hearing defects and tinnitus in patients with congenital nystagmus was very interesting.
In some cases congenital nystagmus may present diagnostic problems, particularly in the cases of CN coinciding with disturbances of equilibrium