Internuclear Isolated

Ophthalmoplegia of Abduction

Impairment of Phasic Ocular

Motor

Activity

in

Supranuclear Lesions

Guntram Kommerell, MD

Abduction saccadic movement slowed to either side without any limitation in the end position occurred in a patient. This ocular motor abnormality constituted a mirror image of the well-known internuclear ophthalmoplegia of adduction, and therefore, the present case is an internuclear ophthalmoplegia of abduction. Internuclear ophthalmoplegia of either type demonstrates that a lesion between the center for conjugate gaze and the ocular motor nuclei can impair phasic activity of the eye muscles without reducing their tonic function.

Internucl ear adduction

diagnosis.

ophthalmoplegia of

is

a

well-established

contradiction, occur¬ rence of internuclear ophthalmo¬ plegia effecting abduction is debated. Such an entity was postulated on a logical basis by Lutz.1 However, it seemed to be impossible to distin¬ guish internuclear ophthalmoplegia of abduction from abducens palsy. In

This report documents a case in which only phasic abduction move¬ ments

(saccadic)

are

affected, leaving

tonic abduction undisturbed (case 1). It is suggested that this ocular motor abnormality constitutes an "inter¬ nuclear ophthalmoplegia of abduc¬ tion." Submitted for publication March 13, 1974. From the Universit\l=a"\ts-AugenklinikFreiburg, West Germany.

Reprint requests to Universit\l=a"\ts-Augenklinik, Killianstr., 7800 Freiburg, West Germany (Dr. Kommerell).

For comparison, a case with inter¬ nuclear ophthalmoplegia of adduction is added (case 2). In this case, adducting saccadic movement of the right eye is slow, without any lack of tonic adduction. METHODS were measured by Horizontal eye devia¬ tions were recorded from miniature AgAgCl skin electrodes (Beckman) glued near the inner and outer canthi of both eyes. Vertical eye deviations and blink artefacts were recorded from a pair of electrodes glued to the skin at the superior and infe¬ rior rim of one orbit. Corneoretinal poten¬ tials from each eye were coupled to three channels of a nystagmograph (Tönnies) using direct current. Filters were set to 10 Hz (—3 dB) to reduce noise. The resultant damping of the trajectory trace was iden¬ tical in all channels and acceptable to the purpose of this study. All recordings were inkwritten on a mingograph (Siemens) at a chart speed of 10 cm/sec. The patients sat in a modified dental chair with two occipital head rests to re¬ duce movements. Fixation targets were small white lamps mounted on a grey background at distances to subtend visual angles of 0°, 10°, 20°, and 30° to the left and right as well as above and below the patient's eyes. Saccadic movements of 10°, 20°, and 30° were recorded from and to

Eye movements electrooculography.

primary position. Optokinetic nystagmus was obtained with the patient looking at a moving stripe pattern that filled most of his visual field. Vestibular nystagmus was elicited by rotating the patient's chair, with acceleration controlled electronically.

The case

2

electromyographic recordings in taken from bipolar concentric

were

30-gauge needle electrodes after instilla¬ tion of anesthetizing drops into the con¬ junctival sac. The horizontal synergis-

tic muscles were recorded simultaneously, first the right medial rectus with the left lateral rectus and then the right lateral rectus with the left medial rectus. The pa¬ tient was asked to execute horizontal sac¬ cadic movements of various amplitudes. Signals were stored on a magnetic tape and photographed from a two-channel os¬ cilloscope at a chart speed of 200 cm/sec. The time constant of the system was set to 0.01 second.

REPORT OF CASES Case 1.—A 5-year-old white girl (born Jan 9, 1968) was referred for neuro-ophthalmological consultation because of pecu¬ liar eye movements seen by the Pediatrie Service of the University of Freiburg. The child did not complain of any eye symp¬ toms. At the age of six months, the girl had been hospitalized for the first time be¬ cause of severe rachitis that, after a laparotomy and a liver biopsy at the age of two years, was regarded to be secondary to "recurrent intrahepatical cholostasis." A congenital disorder of cholic acid metabo¬ lism was suspected. A distressing pruritus was probably due to cholic acid in the skin. The child was too short for her age by 10 cm.

On neurc-ophthalmological examination, the girl was reasonably cooperative. The most conspicuous finding was a slowness of abduction saccadic movement in both eyes, while the speed of adduction saccadic movement was about normal. Electrooculog¬ raphy showed that peak velocity of ab-

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duction saccadic movement was reduced to less than half the peak velocity of adduc¬ tion saccadic movement (Table, Fig 1). This difference between abduction and ad¬ duction saccadic movement is far beyond normal variation.2·3 After large saccadic movements, the adducting eye showed two or three dissociated nystagmus beats. Ver¬ sions to the right, to the left, and down¬ ward were complete. Elevation was limited to about 20°. The eyes were parallel in all directions of gaze (Fig 2). The ocular mo¬ tor disturbance was documented by motion pictures. There was no phoria in either di¬ rection demonstrable by MADDOX cylin¬ der testing. Convergence was full with a normal near response of the pupils. On the synoptophore, stereopsis and binocular fu¬ sion between 5° outward and 30° inward were

present.

Optokinetic nystagmus to the right and to the left showed slow jerks in the abduct¬ ing eye. Down-beating optokinetic nys¬ tagmus was normal. On

attempt to elic¬ it up-beating optokinetic nystagmus, the an

lids retracted rhythmically, but the eyes remained still. There was no spontane¬ ous nystagmus under FRENZEL glasses. Warm-water caloric stimulation in either ear and vestibular stimulations on a ro¬ tating chair produced symmetrical nys¬ tagmus responses whose jerks were slow in the abducting eye. Visual acuity was 1.0 in both eyes, and visual fields were full to confrontation. The fundi showed a normal appearance. There was no Kayser-Fleischer ring in the cornea. The audiogram was normal. The electroencephalogram was dysrhythmic without a focus. Echography (Ultrasound B-sector-scan) showed distention of the third ventricle to 7 mm and of the lateral ventricles to 20 mm. Oth¬ erwise, the results of neurological exami¬ nation were unremarkable. A follow-up ex¬ amination, four months later, showed the ocular motor disturbances to be un¬

changed. Case 2.-A

24-year-old white

woman

(born, Jan 23, 1949) had slightly blurred vi¬ sion of the left eye with retrobulbar pain during eye movements for two weeks pre¬

ceding examination. Medical history

had been unremarkable otherwise, except for a common cold a few days before the present illness.

On neuro-ophthalmological examination,

visual acuity was reduced to 0.5 in the left eye as contrasted to 1.2 in the right eye. In the left eye, there was some difficulty in reading the Ishihara charts, and profile perimetry (Tübingen perimeter) was flattopped. In the swinging flashlight test, an afferent impairment of the pupillary light reflex could not be seen. Two weeks later, vision of the left eye was normal. The

op

30°

Right

0o

1

sec

Fig 1.—Electronystagmographic record of 30° horizontal saccadic movements. Ab¬ ducting eye is always slow. Dissociated nystagmus of adducting eye is seen after refixa¬

tion from 0° to 30° left. Correction of overshoots in left eye after saccadic movement to right may be regarded as "glissadic"4 or rather as slow phase of gaze-evoked nystagmus beat (case 1 ).

Peak Velocity of 20° Saccadic Movement From and to Saccadic

20° Left -> 0° ,-*-,

Move-

ment_OS

1_320 2_250 3_300 4_280 5_300

"Abducting

diagnosis of the left eye

a

eye is

OD

20° Left 20° Right ,-*--, ,-"-, OS OD_OS

130_150 140_150 145_120 160_150 180_140

Ocular Motor

Internuclear ophthalmoplegia of abduction. Isolated impairment of phasic ocular motor activity in supranuclear lesions.

Abduction saccadic movement slowed to either side without any limitation in the end position occurred in a patient. This ocular motor abnormality cons...
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