Compared study of optokinetic and caloric nystagmus in children with unilateral hyporeflexia and other vestibular disorders.
The authors compare the nystagmus evoked by the caloric test and by two slow and fast optokinetic 'look' stimulations performed in 78 subjects subdivided into two groups and recorded by ENG: group 1 composed of 22 subjects with 'significative' unilateral hyporeflexia and group 2 composed of 56 subjects with important anomalies at the vestibular caloric test. The results can be summarized as follows: 1. the presence of unilateral vestibular hyporeflexia is not exceptional in the child: 22 over 140 cases (15.7%); 2. the comparison between the caloric test and the OKN test in the 22 subjects with significant unilateral hyporeflexia shows: slow and fast TAP homolateral to the side with labyrinthine deficit prevails in ten subjects (45.4%); TAP is inconsistency with respect to the hyporeflexic side (i.e. homolateral in one test and contralateral in the other) in seven cases (31.8%); TAP is contralateral in five cases (22.7%). Within the same group, STAP varies according to cases. 3. In group II, TAP values at the OKN test overlap considerably with respect to the caloric test (18 cases with a total TAP prevailing on the right side, 32.2%; 19 cases with divergent TAP, 33.9%; 19 cases with total TAP prevailing on the left side, 33.9%). 4. The data shown in group 1 with significant vestibular hyporeflexia can be correlated to the time elapsed between the last electronystagmography and that performed soon after disease onset. Since for ENG performed some days after vertigo onset (even though clinical examination is negative) shows a concordance of OKN TAP and the hyporeflexic side (as the mechanisms of central compensation are still being developed) and then when these mechanisms improve with time, an inconsistency of OKN TAP and hyporeflexic side and finally a contralaterality. We might rely on the comparison between OKN TAP and caloric test as a finding of the time distance from the vertigo onset (when unknown) and a rough prognostic sign. The only case of vestibular neuritis by us followed in time seems to confirm our assumption.
D'Agostino
R
R
Otolaryngology Department, Istituto Giannina Gaslini, Genoa, Italy.
Melagrana
A
A
Ravera
B
B
Taborelli
G
G
D000293:Adolescent; D002150:Caloric Tests; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D017120:Nystagmus, Optokinetic; D009760:Nystagmus, Physiologic; D012021:Reflex, Abnormal / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D014717:Vertigo / Q000503:physiopathology; D015837:Vestibular Diseases / Q000503:physiopathology*; D020338:Vestibular Neuronitis / Q000503:physiopathology