Sample Type / Medical Specialty: Ophthalmology
Sample Name: Electronystagmogram
Description: Abnormal electronystagmogram demonstrating prominent nystagmus on position testing in the head hanging right position.
(Medical Transcription Sample Report)
PROCEDURE: This tracing was obtained utilizing silver chloride biopotential electrodes placed at the medial and lateral canthi at both eyes and on the superior and inferior orbital margins of the left eye along a vertical line drawn through the middle of the pupil in the neutral forward gaze. Simultaneous recordings were made in both eyes in the horizontal direction and the left eye in the vertical directions. Caloric irrigations were performed using a closed loop irrigation system at 30 degrees and 44 degrees C into either ear.
FINDINGS: Gaze testing did not reveal any evidence of nystagmus. Saccadic movements did not reveal any evidence of dysmetria or overshoot. Sinusoidal tracking was performed well for the patient's age. Optokinetic nystagmus testing was performed poorly due to the patient's difficulty in following the commands. Therefore adequate OKNs were not achieved. The Dix-Hallpike maneuver in the head handing left position resulted in moderate intensity left beating nystagmus, which was converted to a right beating nystagmus when she sat up again. The patient complained of severe dizziness in this position. There was no clear-cut decremental response with repetition. In the head hanging left position, no significant nystagmus was identified. Positional testing in the supine, head hanging, head right, head left, right lateral decubitus, and left lateral decubitus positions did not reveal any evidence of nystagmus.
Caloric stimulation revealed a calculated unilateral weakness of 7.0% on the right (normal <20%) and left beating directional preponderance of 6.0% (normal <20-30%).
IMPRESSION: Abnormal electronystagmogram demonstrating prominent nystagmus on position testing in the head hanging right position. No other significant nystagmus was noted. There was no evidence of clear-cut caloric stimulation abnormality. This study would be most consistent with a right vestibular dysfunction.
Keywords: ophthalmology, silver chloride biopotential electrodes, inferior orbital margins, lateral canthi, vestibular dysfunction, prominent nystagmus, head hanging, electronystagmogram, eyes, nystagmus,