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Abnormal Vertical
Eye Movements in the
Locked-in Syndrome
P. Larmande, MD," D. H h n , MI>,fM . Jdn, MDJ
A. Elie, MD,$ and A. Gouazt, MlIt

As a rule, vertical ocular movements are thought to
depend on niesencephalic structures, horizontal gaze
on pontine structures. The ocular motility examination of a patient with pontine hernorrhage and no lesion of the niesencephalon showed bilateral palsy of
horizontal gaze and a dissociated loss of vertical
movements: saccades were slowed, while pursuit managements were unchanged. The findings suggest that
the pontine reticular formation is necessary in generation of normal vertical ocular saccades.
Larmande P, l-I&iin D, Jan M, Elie A, Gouaze A:
Abnormal vertical eye movements i n the lockrd-in
syndrome. Ann Neurol 11:lOO --102, 1982

The locked-in syndrome, identified by Plum and
Posner [12], is a rare clinical entity consisting of
tetraplegia with facial paralysis and bilateral paresis
of horizontal gaze. The only remaining voluntary
movements are blinks of the eyelids, which allow
contact with the patient, anti vertical eye movements,
which are usually maintained.
No qualitative study of the vertical eye nioveinents
in locked-in syndrome has been published, but these
movements are often described as normal [7,111. In
one of our patients suffering from locked-in syndrome, we could confirm the presence of vertical
ocular movements. The clinical and graphic recorded
abnormalities of these movements a r e described.
Case Report
A 50-year-old woman with longstanding hypertension was
admitted after she suffered a left heiiiiplegia without loss
of consciousness. lrnmediately following admission her
condition deceriorared severely: bilateral hemipfegia developed associated wirh respiratory paralysis that necessitated tracheal inrubation and assisted ventilation. Nevertheless, the patient remained conscious and communicated

From the *Clinique Neurologique and the tService de Neurochirurgie, C.H.R. de Tours, Tours, France, and t h e $Service
d'Anatoinie Pathologique, C.€I.R.Beaujou, Clichy, France.
Received Feb 9, 1981, and in reviseJ form May 1.Accepted for
publicatiori May 1 1 , 1981.
Address reprint requests tu t)r l.drmaide, Clinique Neurdogique,
Centre Hospitalier K6giunal de Tours, 2, Hd Tonntlli, 37044
Tours C d e x , France.

100 0364-5 134/821010100-03$01 2 5 @ 178 1 by the American Neurological Association

and lV), was normal, as were the medial longitudinal fasciculus and the mesencephalic reticular formation (MRF).
In the upper part of the pons, the lesions were mainly
located in the tegmentum next to the fourth ventricle, and
involved the superior central nucleus, the medial longitudinal fasciculus, the medial lemniscus, and the central
tegmental tract. The hemorrhage had spared the ventral
part. In the middle pons the hemorrhage had a similar topography, destroying the middle tegmentum next to the
fourth ventricle. T h e ventral pons and middle cerebellar
peduncles were free of lesions. In the lower pons the
hemorrhage affected only the middle part of the tegmenrum, involving the fibers of the root of the abducens nerve
(VI). T h e nucleus was intact. The medulla, cerebellum, and
hemispheres showed no lesions. There was moderate arteriosclerosis of the basilar artery without stenosis o r
thrombosis.
Massive recent pontzne hemorrhagc.. In the upper part of the
D o n ( , lesions are mainly located i n the tegmentum next t o the
fourth tvntrzrle. I n the l o u w part of the porn the hemorrhage
is less marked. (Cellozdiri sectzons, Lojrz’s myelzn zmpregnat2on.J

by blink. Both pupils measured 3 mm and reacted correctly. The eyes were parallel; no abnormal sponcaneous
movements were noticed. In the horizontal plane, the patient was unable to move her eyes: voluntary pursuit and
caloric movements were absent. In the vertical plane, eye
movements appeared unrestricted. She directed her gaze
voluntarily and followed a target. The fast vertical eye
movements, however, appeared abnormally slow.
The speed of vertical ocular movements was measured
by oculographic recording: silver-silver chloride electrodes were placed in the horizontal and vertical planes and
coupled with a DC amplifier. Signals were recorded on a
polygraph. The speed was identical upward and downward
for a given amplitude: 8 5 degrees per second for a 20degree amplitude, 135 degrees per second for a 45-degree
amplitude, and 140 degrees per second for a 70-degree
amplitude. Normal speed according to our laboratory
standards is 175,200, and 250 degrees per second, respectively, for these amplitudes.
Visual pursuit movements were normal: the eyes precisely followed the moving object. Vertical optokinetic
nystagmus, both upward and downward, produced a slow
movement of the eyes in the direction of rotation of the
Barany drum without the opposite quick phase, indicating
that the quick phase of vertical optokinetic nystagmus is
suppressed. Vertical oculovestibular reflexes were absent
both with caloric stimulation and with the “doll’s-head”
maneuver.

Neuroputhofogicuf Objervutions
Brainstem sections embedded in celloidin and stained with
hematoxylin and eosin and Loyez’s myelin impregnation
displayed a recent and extensive pontine hemorrhage (Figure). T h e midbrain, in particular the oculomotor nuclei (111

Discussion
Paralysis of horizontal gaze is a classic feature of
pontine lesions, linked here to destruction of the two
pontine reticular formations (PRF). The absence of
vertical oculocephalic reflexes can be explained by
interruption of ascending connections between the
vestibular system and oculomotor nuclei within
either the medial longitudinal fasciculus or the
brachium conjunctivum [6]. Slowing of vertical saccades, however, has not been described with human
pontine lesions.
Christoff [ 51 observed disappearance of upward
movements of the eyes with persistence of downward
movements in bilateral pontine lesions. However, he
made no distinction between voluntary and tracking
movements. Bender and Shanzer [ 11 described the
absence in monkeys of upward saccades with
paramedial lesions of the pons and of downward saccades with lesions of the mesencephalon. After bilateral lesions of the medial longitudinal fasciculus in
monkeys, Evinger et a1 [6] observed dissociation of
vertical movements: the saccades appeared normal
but tracking movements were jerky, and the animal
had great difficulty maintaining fixation in upward
and downward positions. These investigations prove
that the PRF influences control of vertical movements. Our study demonstrates that vertical saccades
specifically are under its control.
The point is the relationship between the MRF
and PRF in control of vertical saccades. Presently,
anatomical [13] and physiological [2, 4 , 101 studies‘
indicate that the rostra1 part of the MRF generates
vertical saccades. Numerous cells in the PRF also discharge during vertical saccades. The latter discharge
precedes that of the MRF, suggesting that the MRF is
controlled by the PRF [S, 91. In support of this hypothesis, Buttner-Ennever [3J has demonstrated the
existence of a direct ascending anatomical pathway
between the two structures.

Brief Communication: Larmande et al: Eye Movements in Locked-in Syndrome

101

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102 Annals of Neurology

Vol 11 No 1 January 1982

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