Electrophysiological brainstem testing in the diagnosis of reversible brainstem ischemia

Abstract

The aim of this study was to evaluate the sensitivity of multimodal electrophysiological brainstem testing in the diagnosis of clinically suspected reversible ischemic deficits of the brainstem compared with diffusion weighted MR imaging. We investigated 158 consecutive patients presenting with signs of acute brainstem dysfunction. Serial electrophysiological brainstem tests including masseter reflex, blink reflex, masseter inhibitory reflex, AEP, MEP, EOG and the oculoauricular phenomenon were applied. In 14 of the 158 patients neurological deficits resolved in less than 24 hours, which was suggestive of a transitory ischemic attack (TIA), 19 patients had brainstem signs for more than 24 hours but less than 1 week, suggestive of a reversible ischemic neurological deficit (RIND). Electrophysiological data indicated acute functional brainstem lesions in 54,5 % of patients with transient clinical brainstem impairment. Lesion detection rate was significantly higher when combining electrophysiological data and MRI (60,4 %) than using acute brainstem abnormalities in diffusion weighted MRI alone (39,4 %). We conclude that diffusion weighted MRI and electrophysiological brainstem testing are complimentary sensitive indicators of acute brainstem lesions in patients with reversible neurological deficits. Correct identification of brainstem ischemia influences the therapeutic regimen and may improve patient outcome.

Medullary infarcts may cause ipsilateral masseter reflex abnormalities

“…MassR abnormalities with medullary lesions restrict the topodiagnostic value of the MassR. The reflex is highly sensitive in detecting the existence of brainstem lesions,10 but appears less useful in determining the level of the lesion in the craniocaudal axis 3…”

Die elektrophysiologische Untersuchung des Masseterreflexes

“…Tab. 1 Normwerte der Masseterreflexlatenzen bei verschiedenen Studien Schichten hat sich der MR-tomographische Nachweis von Hirnstammläsionen ohne jeden Zweifel erheblich verbessert, erfasst aber auch jetzt nicht alle funktionell relevanten Hirnstammläsionen[39,40,52]. In diesem Zusammenhang ist an den grundlegenden Unterschied zwischen bildgebenden und elektrophysiologischen Untersuchungsverfahren zu denken.…”