Vertigo and imbalance caused by a small lesion in the anterior insula.
The exact location of the vestibular cortex in humans has not yet been established. Isolated lesions in the insula are exceptional. We describe a patient with recurrent episodes of vertigo and imbalance following a small lesion in the anterior insula. Myogenic and neurogenic vestibular evoked potentials were both performed using auditory stimuli. The former was recorded from the sternocleidomastoid muscle and the latter from the parietal areas on the scalp. Brainstem auditory evoked potentials, threshold latency series, pure tone audiometry and video nystagmography were also performed, as was brain MRI. All evoked potential studies and pure tone audiometry were within normal limits, ruling out peripheral and brainstem causes for the patient's symptoms. Video nystagmography revealed high slow phase velocities bilaterally with caloric stimulation, and saccadic tracking on the smooth pursuit examination. The MRI revealed a small lesion in the right anterior insula. To our knowledge this is the first reported case of vestibular symptoms and signs from a lesion in the anterior insula on MRI. In addition, its effects on the nystagmogram suggest that this area may be part of the pathway that controls smooth pursuit.
Papathanasiou
E S
ES
Department of Clinical Neurophysiology, The Cyprus Institute of Neurology & Genetics, 6 International Airport Avenue, P.O. Box 23462, Nicosia 1683, Cyprus. neurophy@cing.ac.cy
Papacostas
S S
SS
Charalambous
M
M
Eracleous
E
E
Thodi
C
C
Pantzaris
M
M
D000328:Adult; D001301:Audiometry, Pure-Tone; D001927:Brain Diseases / Q000150:complications*; D002150:Caloric Tests; D002540:Cerebral Cortex / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic; D004856:Postural Balance; D011698:Pursuit, Smooth / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012008:Recurrence; D012438:Saccades / Q000502:physiology; D012678:Sensation Disorders / Q000209:etiology*; D012684:Sensory Thresholds / Q000502:physiology; D014717:Vertigo / Q000209:etiology*; D014722:Vestibule, Labyrinth / Q000503:physiopathology