gms | German Medical Science

Objective: The extent of brainstem damage after severe traumatic brain injury (TBI) is critical for the evaluation of patient outcome. This has been demonstrated by previous studies employing imaging techniques to visualize structural or functional brainstem lesions. Accordingly, changes in the oculomotor response (OMR) to galvanic labyrinth polarization (GaLa) recorded soon after TBI should equally indicate the outcome of patients.

Methods: The proposed vestibulo-ocular monitoring technique (VOM) is based on video-oculographic recording of eye movements during GaLa stimulation of both labyrinths. The OMR is elicited via the vestibulo-ocular reflex (VOR), i.e. via the afferents from the peripheral neurons to the vestibular nuclei and subsequently to the oculomotor neurons. These pathways are situated in the brainstem and therefore reflect alterations caused by a functional lesion. The aim of the study is to examine whether, and to what extent, early VOM correlates with outcome after six months (Glasgow Outcome Score) in severe TBI.

Results: VOM was performed on twenty-seven patients within three days after severe TBI. GOS was determined by evaluation of a standardised outpatient interview. Three-dimensional eye movements were obtained from the VOM recordings and frequencies analysed. In 16 patients an OMR, synchronous with the GaLa stimulus was found. In the remaining 11 patients no such OMR could be observed. One patient was excluded from the study. Outcome scores yielded GOS1 (n=11), GOS2 (n=3), GOS3 (n=9), GOS4 (n=3) and GOS5 (n=1).

Conclusions: Using VOM in the acute phase it was possible to predict the patients’ outcome by distinguishing two groups. GOS1–2 determined six-months after trauma was characterised by no OMR, whereas GOS3–5 showed an OMR (exact two-sided Fisher-Test (p<10^-3)). As an indicator of brainstem function VOM provides a useful approach complementary to the identification of brainstem lesions by imaging techniques.