• 9 SECTIONDisorders Gaze Cerebral

Congenital Ocular Motor Apraxia

Key Facts

•Horizontal eye movement disorder identified within first year of life

•Horizontal voluntary eye movements (saccades and pursuit) are absent but reflex (vestibulo-ocular) horizontal eye movement is intact (ocular motor apraxia)

•All vertical eye movements are intact

•Child blinks and thrusts head in direction of intended horizontal gaze

•Usually a form of delayed maturation of brain, with spontaneous recovery by second decade, but may be associated with other developmental, progressive metabolic, or degenerative neurologic conditions

Clinical Findings

•Horizontal saccades and pursuit are impaired or absent but vestibulo-ocular reflex, tested with doll’s head maneuver, is intact

•All vertical eye movements are intact

•Child blinks and thrusts head in direction of intended horizontal gaze

•Developmental delay is common

•Other neurologic deficits may be present

Ancillary Testing

•Brain imaging usually normal but may show:

•midline dysgeneses

•signs of perinatal ischemia

•heterotopias

•Metabolic screening indicated if there are other neurologic abnormalities

Differential Diagnosis

•Head thrusts may be misinterpreted as part of an involuntary movement disorder

•Myasthenia gravis

•Genetic extraocular myopathy

Treatment

• None

Prognosis

•If the ocular motor apraxia is an isolated finding, patients spontaneously recover normal eye movements by second decade

A

B

C

Fig. 9.1 (A) A patient is unable to generate any horizontal eye movements to command, either by saccades or pursuit. (B) When the patient wishes to look at a target to his right, he thrusts his head toward the right. This thrust elicits a contraversive reflex binocular eye movement to the left, which places his eyes to the left of the target he intends to view. (C) He moves his head slowly to the left, eliciting a reflex binocular eye movement to the right in order to place his eyes on the target. When reflex eye movements are more ample than volitional eye movements, the disorder is called apraxic or supranuclear.

Apraxia Motor Ocular Congenital

• 9 SECTIONDisorders Gaze Cerebral

Acquired Ocular Motor Apraxia

(Supranuclear Gaze Palsy)

Key Facts

•Acquired loss of all voluntary eye movements (saccades and pursuit) with preserved reflex eye movements (ocular motor apraxia)

•Also called a supranuclear gaze disorder

•Doll’s head maneuver elicits reflex eye movements by drawing on intact vestibulo-ocular reflex

•Common causes:

• progressive supranuclear palsy (PSP) • bilateral frontoparietal infarcts

• Alzheimer disease

Clinical Findings

•Voluntary saccades and pursuit in all planes are reduced or absent

•Doll’s head maneuver extends amplitude of horizontal and/or vertical gaze

•Other neurologic manifestations:

•impaired visuospatial function (Alzheimer disease, frontoparietal infarcts)

•ataxia (ataxia telangiectasia) • rigidity • masked facies (PSP) • cognitive decline (Niemann–Pick disease type C) • pendular convergence nystagmus and rhythmic twitching of masticatory and limb muscles (Whipple disease)

•memory loss (Alzheimer disease)

•Non-neurologic manifestations:

•visceromegaly (Niemann–Pick type C) • blepharitis (PSP) • diarrhea (Whipple disease) • sinopulmonary infections (ataxia telangiectasia)

Ancillary Testing

•PSP: brain imaging may be normal or show atrophy of superior colliculus, low T2 signal in putamen (iron deposition)

•Ataxia telangiectasia: superior cerebellar vermis atrophy

•Bilateral frontoparietal infarcts: MRI signal abnormalities in affected brain regions

•Whipple disease: small bowel biopsy for periodic acid Schiff positivity in macrophages or PCR test for Tropheryma whippelii DNA in spinal fluid

•Neimann–Pick type C: bone marrow biopsy for sea-blue histiocytes, foam cells

Differential Diagnosis

•PSP • Bilateral frontoparietal infarcts • Alzheimer disease • Ataxia telangiectasia • Niemann–Pick disease type C • Whipple disease • Wilson disease • Psychogenic lack of cooperation

Treatment

•PSP: supportive care

•Ataxia telangiectasia: supportive care, treat infections as they develop

•Bilateral frontoparietal infarcts: supportive care

•Whipple disease: intravenous ceftriaxone or trimethoprim–sulfamethoxazole

•Niemann–Pick type C: supportive care

•Wilson disease: tetrahydromolybdate

Prognosis

• Depends on condition

A

B

Fig. 9.2 (A) A patient is unable to generate any horizontal or vertical eye movements to command, either by saccades or pursuit. (B) Passive movement of the patient’s head (doll’s head maneuver) elicits contraversive reflex eye movements. Two differences between congenital and acquired ocular motor apraxia are: 1, in the congenital form, volitional gaze palsy is limited to the horizontal plane; 2, in the acquired form, head thrusts are not common.

Fig. 9.3 Acquired ocular motor apraxia caused by bilateral frontoparietal infarcts. Diffusion-weighted MRI discloses high signal areas in the watershed frontoparietal regions bilaterally (arrows) in a patient who developed severe systemic hypotension during heart transplant surgery.

Palsy) Gaze (Supranuclear Apraxia Motor Ocular Acquired