Transient post-traumatic locked-in syndrome: a case report and a literature review.

Introduction: Post-traumatic locked-in syndrome may be particularly difficult to recognize, especially when it follows a state of coma and presents the clinical feature of a "total" locked-in syndrome.

Patient And Methods: A 56-year-old male with a closed head injury was admitted in intensive care unit (ICU) with GCS=4 (V1, M2, E1). Computed tomography (CT) scan disclosed a limited subarachnoid haemorrhage in the sylvian region without any brain oedema or ventricular shift. The GCS did not change until day 6. At the same time EEG showed a reactivity to acoustic stimuli consisting in the paradoxical appearance of a posterior rhythm in alpha range (10-12c/s), blocked by passive eye opening. Early cortical components (N20-P25) of somatosensory evoked potentials were normal on both hemispheres; middle components were also clearly evident. Magnetic resonance imaging of the brain showed both diffuse and midbrain axonal injuries, particularly in a strategic lesion involving both cerebral peduncles. Event related potentials showed N2 and P3 components to stimulation by rare tones.

Conclusions: A comprehensive multimodal neurophysiological approach, using the more informative tests and the proper time of recording, should be included in protocols for patients with severe head trauma, in order to establish the actual patient's clinical state and to avoid that a locked-in syndrome state be mistaken for prolonged coma, vegetative state, minimally conscious state or akinetic mutism. Neurophysiological evaluation before discharge from ICU can be a baseline evaluation useful for the follow-up of low-responsive patients in the neuro-rehabilitation unit.