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This Week In The Bmj

Locked-in syndrome

BMJ 2005; 330 doi: https://doi.org/10.1136/bmj.330.7488.0-f (Published 17 February 2005) Cite this as: BMJ 2005;330:0-f

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Locked in Syndrome

We read with interest your article on Locked in Syndrome. It was
mentioned that horizontal gaze palsies are typical, retaining upper eyelid
control and vertical eye movement due to sparing of the mid-brain tectum.
Horizontal eye movements are generated from the horizontal gaze centre in
the Paramedian Pontine Reticular Formation (PPRF). Combined lesions of the
PPRF and Medial Longitudinal Fasiculus(MLF) lead to “one and a half
syndrome” with the only horizontal eye movement being adduction of the
contralateral eye. Congenital ocular motor apraxia is a rare condition
with no voluntary horizontal saccades and normal vertical saccades.

Vertical eye movements are generated from the vertical gaze centre
known as the rostral interstitial nucleus of the MLF, located in the
midbrain just dorsal to the red nucleus. Lesions here cause Parinaud’s
syndrome.

Comatose patients should be carefully examined to distinguish the
persistent vegetative state from the locked-in syndrome. History from
eyewitnesses along with a rapid neurologic examination focusing on
pupillary responses, eye movements, and motor responses are important.
Pupils unreactive to light often point to a structural brain lesion and
the need for urgent neurosurgical consultation. Ophthalmolplegia with
preservation of vertical eye movement suggest Locked in Syndrome. (1)

The fact that vertical eye movements and blink reflex are generally
preserved help protect against corneal ulceration. If there is impaired
eye closure, regular topical eye lubricants should be used. Lateral
tarsorrhaphy partially closes the palpebral aperture to reduce tear
evaporation and helps protect the cornea. It is often used in patients
with long standing Bell’s palsy. Botulinum toxin injection to the levator
muscle is another option which lasts a variable time, usually a few
months. Avoiding full eye closure may be preferable as it will prevent
communication.(2)

A study of 12 patients with locked-in syndrome suggested a criteria
of classical locked-in syndrome (LiS), with total immobility except for
vertical eye movements and blinking. Incomplete LiS describes any other
movements present. Total immobility, including all eye movements, combined
with signs of undisturbed cortical function in the EEG led to the concept
of total LiS. Chronic and transient forms of LiS have been described. (3).

Fifteen reported cases of LiS with full recovery have documented
recovery of lateral gaze in the early stage. In addition, smooth
horizontal gaze is the most frequent activity in incomplete LiS. Early
recovery of horizontal eye movement may indicate that the brain lesion is
limited and may be a good prognostic sign in LIS. (4)

1) Plum F, Posner JB. The diagnosis of stupor and coma. Philadelphia,
PA: FA Davis, 1966.

2)Leon-Carrion J, van Eeckhout P, Dominguez-Morales Mdel R, Perez
Santamaria FJ. The locked-in syndrome: a syndrome looking for a therapy.
Brain Inj 2002;16: 571-82

3) Bauer G. Gerstenbrand F. Rumpl E.Varieties of the locked-in
syndrome. Journal of Neurology. 1979; 221(2):77-91

4) Yang CC. Lieberman JS. Hong CZ. Early smooth horizontal eye
movement: a favourable prognostic sign in patients with locked-in
syndrome.
Archives of Physical Medicine & Rehabilitation. 1989; 70(3):230-2

Competing interests:
None declared

Competing interests: No competing interests

20 February 2005
Tanya N Moutray
Ophthalmology SHO
Michael Williams
Royal Victoria Hospital, Grosvenor Rd, Belfast,BT12 6BA