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locked-in syndrome; cognitive-motor dissociation

Etiology: 1) lesions involving the ventral pons bilaterally 2) basilar artery thrombosis or embolism 3) traumatic brain injury [3] Clinical manifestations: 1) quadriplegia 2) loss of lower cranial nerve function 3) wakefulness & awareness of the environment 4) vertical eye movements & blinking are often preserved - may be only mechanism for patient to communicate with the outside world 5) preserved tendon reflexes 6) Babinski's sign 7) abnormal pupillary reflexes Laboratory: - electroencephalography (EEG) is often normal Radiology: - 25% of patients with traumatic brain injury show MRI &/or EEG evidence of cognitive-motor dissociation [3] Differential diagnosis: - cataplexy

General

disease/disorder primarily affecting brain syndrome

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1074
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
  3. George J One in Four Brain Injury Patients Who Appear Unresponsive Respond Covertly. Functional MRI and EEG detect awareness in coma or vegetative states. MedPage Today, August 14, 2024 https://www.medpagetoday.com/neurology/generalneurology/111520 - Bodien TG et al Cognitive Motor Dissociation in Disorders of Consciousness. Engl J Med. 2024. Aug 14. PMID: 39141852 https://www.nejm.org/doi/full/10.1056/NEJMoa2400645