Relationship Between Sleep Spindles and Clinical Recovery in Patients With Traumatic Brain Injury

Abstract

Few methods can predict the prognosis and outcome of traumatic brain injury. Electroencephalographic (EEG) examinations have prognostic significance in the acute stage of posttraumatic coma, and some EEG variables have been correlated with outcome. Furthermore, spindle activity and reactivity in the acute stage have been associated with good recovery. Assessments of consciousness based on EEG and magnetoencephalographic (MEG) recordings provide valuable information for evaluating residual function, forming differential diagnoses and estimating prognosis. This study objectively investigated how fast spindles could relate to the recovery of consciousness and cognitive function during the post-acute to chronic stages of diffuse axonal injuries (DAIs). Sleep stage 2 was examined in 7 healthy participants and 8 patients with DAIs. Simultaneous EEG and MEG recordings were performed in the post-acute (mean 80 days) and chronic (mean 151 days) stages of recovery. Magnetoencephalography enabled equivalent current dipole estimates of fast spindle sources. Clinical recovery was evaluated by consciousness, neuropsychological examination, and outcome. Six severe and two moderate injuries were studied in patients with favorable 1-year outcomes. In the sub-acute stage, significant decreases were detected in the frequency, amplitude, and cortical activation source strengths of spindle activities, but these recovered during the chronic stage. In the chronic stage, the Wechsler adult intelligence factor scale and subset patterning revealed significant improvement in cognitive function. These results suggested that spindles may reflect recovery of consciousness and cognitive function following a DAI.

Sleep Features on Continuous Electroencephalography Predict Rehabilitation Outcomes After Severe Traumatic Brain Injury

“…14 The presence of sleep-wake cycles defines the threshold between comatose states and consciousness. 15 Studies in patients undergoing rehabilitation following brain injury have suggested that the emergence of more complex sleep architecture parallels cognitive recovery [16][17][18][19] and correlates with improvement in clinical outcome in brain-injured adults 20 and children. 21 Furthermore, the presence of sleep spindles and rapid eye movement sleep in brain-injured patients in persistent vegetative or minimally conscious states predicted return to consciousness within 6 months.…”

Electrophysiologic Evaluation of Diffuse Axonal Injury after Traumatic Brain Injury

“…Medial components of the posterior intralaminar region of the central thalamus are involved in spindle generation. Therefore, the recovery of consciousness may be strongly associated with the recovery of sleep spindles after brain injury [30,31]. In patients who have TBI, findings of sleep architecture are inconsistent and may include; no changes, increased slow waves, decreased rapid eye movement sleep, increased rapid eye movement sleep during the second half of the night, no change in rapid eye movement sleep, or decreased onset latency of rapid eye movement sleep.…”

A Review of the Effectiveness of Neuroimaging Modalities for the Detection of Traumatic Brain Injury

“…MEG remains an underused technology in TBI research 258,[326][327][328][329][330][331] and is not used routinely in clinical practice. The available data does not support the use of MEG in the diagnosis of TBI, as the quality of the evidence published to date is low with regard to this specific clinical application.…”