Topographic EEG analysis in two patients with basilar thrombosis

Area of Science:

• Neuroscience
• Clinical Neurology
• Electrophysiology

Background:

• Vertebral and basilar artery occlusion can lead to severe neurological deficits, including locked-in syndrome and vegetative states.
• Assessing brain activity and patient awareness in these conditions is clinically challenging.

Observation:

• Analysis of electroencephalography (EEG) activity in two patients with vertebral and basilar artery occlusion.
• Evaluation of power maps, peak power frequency, and field power differences during photic stimulation and verbal command.
• One patient presented with locked-in syndrome, while the other was in a permanent vegetative state.

Findings:

• EEG analysis documented awareness in the locked-in syndrome patient, showing significant alpha and sub-alpha power reduction during intended movement.
• The vegetative state patient exhibited a nonreactive rhythmic alpha pattern with spontaneous alternating activity, suggesting partial thalamo-cortical connection preservation.
• Regional EEG reactivity differences correlated with underlying hemispheric infarcts.

Implications:

• EEG is a valuable tool for assessing awareness and brain function in patients with severe neurological impairment.
• Understanding EEG patterns in locked-in syndrome and vegetative states can guide clinical management and prognosis.
• Pseudo-periodic alpha activity fluctuations may indicate residual thalamo-cortical connectivity.