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Functional Significance of Peripheral Head‐Shaking Nystagmus
Author(s) -
Pérez Paz,
Llorente José Luis,
Gómez Justo R.,
Campo Alfredo del,
López Aurora,
Suárez Carlos
Publication year - 2004
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200406000-00023
Subject(s) - nystagmus , medicine , audiology , caloric theory , vestibular system , peripheral
Objectives/Hypothesis: The objective was to determine the characteristics of horizontal head‐shaking nystagmus of peripheral origin and its relationship to vestibular dysfunction. Study Design: Retrospective case series. Methods: Eighty‐three patients met the inclusion criteria of having peripheral and unilateral vestibular disease. Patients were tested with video nystagmography. Head‐shaking nystagmus was performed in the horizontal plane during 30 cycles at a frequency of approximately 3 Hz. Head‐shaking nystagmus was classified as monophasic or biphasic and, based on the pathological ear, as ipsilateral or contralateral related to nystagmus fast phases. The two‐tailed t test, ANOVA, Mann‐Whitney and χ 2 tests, and lineal and polynomial regression tests were used for statistical analysis. Results: Twenty‐three patients showed a positive head‐shaking nystagmus. All cases of head‐shaking nystagmus observed were horizontal. There were four biphasic and 19 monophasic cases of head‐shaking nystagmus. First phases of biphasic head‐shaking nystagmus beat toward the normal ear. Eleven of the monophasic cases of head‐shaking nystagmus were ipsilateral, and nine were contralateral. There was a statistically significant correlation between caloric weakness and head‐shaking nystagmus. Ipsilateral head‐shaking nystagmus corresponded to lower caloric asymmetries, and contralateral and biphasic head‐shaking nystagmus corresponded to greater caloric weakness ( P < .001). As the caloric asymmetry increased, the maximal slow‐phase eye velocity of head‐shaking nystagmus was greater ( P = .01) and its duration shortened ( P = .008). Ipsilateral responses could be distinguished from contralateral responses based on their latency ( P = .03), maximal slow‐phase eye velocity ( P < .05), and duration ( P = .02). The frequency of head‐shaking nystagmus was significantly higher among older patients. There was no correlation between head‐shaking nystagmus and clinical patterns. Conclusion: Head‐shaking nystagmus of peripheral vestibular origin is a response both qualitatively and quantitatively associated with the degree of the vestibular loss.