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Show ,. Cli". Nellro-ophllwlmol. 5: 153-157, 1985 Congenital Vertical Ocular Motor Apraxia JANE L. HUGHES, M.D. PATRICK S. O'CONNOR, M.D. PAUL D. LARSEN, M.D. JOHN V. MUMMA, M.D. IlJ 1985 Raven Press, New York Abstract The case of a oI 1J2-year-old boy with congenital vertical ocular motor apraxia who was otherwise developmentally and neurologically normal is reported. The presence of perinatal hypoxia in this patient may have been etiologic. While the presence of a supranuclear vertical ocular motor abnormality usually suggests a serious, acquired neurologic or systemic disease it may rarely occur as an isolated congenital finding, as demonstrated in this case. Congenital ocular motor apraxia has been described as an inability to voluntarily direct horizontal gaze in the presence of intact involuntary movements and in the absence of other serious neurologic disease. l It has been stressed that such defects are always in the horizontal plane and that the presence of a vertical component should suggest an acquired disorder associated with serious and more diffuse neurological and/or systemic disease. The following case represents the first report, to our knowledge, of a predominantly vertical ocular motor apraxia present from birth. This 41h-year-old boy was a 30-week, premature, genetically identical twin weighing 2 Ib, 8 oz at birth. His Apgar score at 1 min was 4, at 3 min it was 1, and at 5 min it was 6; he required immediate intubation and resuscitation in the delivery room. At 7 days of age he was noted to have intermittent opisthotonos and was hy- From the Department of Ophthalmology U. L. H.. P. S. O. J. V. M.) and the Division of Pediatric Neurology (p. D. L.). University of Texas Health Science Center at San Antonio, San Antonio, Texas. This paper was prest'nted In part at the Rocky Mountain Neuro-ophthalmo!ogy Meeting in January 1984. Write for reprints /0: P. S. O'Connor, M.D., Department of Ophthalmology, University of Texas Health SCience Center, 7703 Floyd Curl Drive, San Antonio, IX 78284, U.S.A. September 1985 pertonic. Two computed tomography (CT) scans, an electroencephalogram, and two lumbar punctures were normal. Intermittent hyperbilirubinemia of up to 9.7 mg/dl was treated with a brief course of phototherapy and resolved. The patient was kept on a ventilator for a total of 15 days and his hypertonia and intermittent posturing cleared within 1 month. The patient's identical twin had Apgar scores of 6 at 1 min and 8 at 3 min, was on a ventilator for 7 days, and was also treated for hyperbilirubinemia with phototherapy. He did not, however, have any perinatal neurological deficits. Shortly after birth, as the patient began to respond, his parents noted that his eyes were fixed in either an upward or downward position, with very little random movement. When attempting to look at objects in his environment he would develop head flexion or extension (Fig. 1). Photographs at age 6 months (Fig. 2) and 15 months (Fig. 3) documented this posturing. This tonic deviation was later replaced by vertical head thrusting when the child wanted to look at specific objects in his environment. We first saw him at the age of 41/2 years for these head movements. On examination, his best corrected vision was 20/40 on the right and 20/30 on the left. Previous evaluation had revealed an intermittent exotropia, which had resolved. Pursuit movements were normal vertically and horizontally. Optokinetic nystagmus was present in the horizontal plane but absent in the vertical plane. Horizontal vestibul<H stimulation yielded slightly dampened but present refixation saccades. Doll's head testing was normal horizontally but accentuated vertically. When the child was tilted backward and then suddenly lifted to an erect position his eyes became fixed in upgaze for some seconds. In addition, he was unable to voluntarily look up or down, although downgaze appeared to be more affected. To voluntarily look at an object in his lap he would throw his head forward past the object, gain fixation 153 Con~l'nit,ll Vl'rtic.1llkul,u Motor Apr,l;\i.l Figure 1. Ph,'t,)"raph 01 patient taken during the first n1l1nth ,,( life. Noli.-e "\,,,S "fwzen" in dOlVngaze. and return his head in line with the object (Fig. 4). A detailed neurological examination, including psychometric testing, revealed normal cranial nerve responses except for eye movements, normal coordination without tremor, and normal finger-to-nose rapid alternating movements. The deep tendon reflexes were 2 + throughout, with normal muscle bulk, tone, and strength. The patient's gait was normal for his age, although his mother felt he was slightly more clumsy than his twin. Psychometric testing revealed a normal IQ with a selective deficit in receptive language ability (he performed 1. 75 years below his chronological age). Both twins had also met their milestones for age, although our patient had lagged slightly behind his brother. A repeat, high-resolution CT scan in April 1984 was normal. Electronvstagmography testing revealed grossly normal optokinetic nystagmus horizontally. Nystagmus developed with Bar~ny c;hair as w~1l as caloric stimulation. Test calibratIon and SinUSoidal tracking were abnormal; both of these are dependent on a voluntary ocular motor response, suggesting a mild horizontal deficit as well as a vertical abnormality. The patient's mother said that his head thrusting had improved remarkably since first observed. Discussion In Cogan's article l on congenital ocular motor apraxia, he described a clinical entity in which there was full inability to voluntarily turn the eves in a direction for which there was fuJI i~voluntary movement and in which there was a characteristic horizontal compensatory head thrust. He described four patients, and since that time at least 60 cases have been reported. 2-1; All of these patients had defective voluntary horizontal gaze and head thrust, with no reported vertical abnormalities. Cogan felt these head thrusts were characteristic of congenital ocular motor apraxia, but these movements subsequently have been noted in acquired cases.~·Y Of the 60 patients whose cases were reviewed, 37 .\'ere male, 20 were female, and 3 were of unspecified sex. Of these, 12 had affected siblings, two of which were identical twins. When tested, optokinetic nystagmus revealed an abormal horizontal but intact vertical response. Most patients were noted to have maturational problems and delayed motor development. Although clumsiness was frequently mentioned, most of the children were of normal intelligence. Various gestational insults and other abnormalities have also been reportedl-~.1i1 (Table 1). The pathogenesis of ocular motor apraxia is unknown. Speculation on pathologic localization has not been based on direct autopsy evidence, and lesions in several different areas Figure 2. Photograph of patient (left) and identi.-a) twin (right) at about age 8 n1'lnths. Note that the patient's eyes are "frozen" in upgaze. 154 Journal of Clinical Neuro-ophthalmology Hughes et al. Figure 3. rh"l,,~raph of patient (lett) ,!Od identic,,1 twin (right) at db"ut 'lge 15 Ill"nth~. N"te a~din thdt the pdtienr~ l'ye~ are "frozen" in d"wn~dzl" have given rise to similar syndromes. II Lesions resulting in ocular motor apraxia have been identified in cortical, basal ganglion, diencephalon, and brainstem areas. II Cogan7 and othersD feel that the lesions may be located in Brodmann's frontal area or its cortical fungal fibers because of the similarities between congenital ocular motor apraxia and acquired forms lal (h) (e) Figure 4. Photographs taken from a Videotape demonstratin~ patil'nt's head thrust when attempting to voluntarily view an objl'ct in hi~ lap, a: After an upward head thrust the patient has fixated on l'X"mil1l'r'~ finger. b: Patient instructed to look at toy placed in hi~ lap, Notl' bl'gillnill~ of head thrust with eye lid closure and position of l'yl'S, c: Oversho(>t of head thrust allowing eyes to gain fixation. d: Rl'lurn of Iwad to position aligned with object. September 1985 155 (d) Cnn~enit,ll Vertit-'lllkulM Motor I\praxia caused by lesions in these areas. Lyle4 and others12 believe that the clinical findings and coexisting central nervous system pathology implicate the brainstem and cerebellum. Zaret et al. 12 reported a case that they felt initially to be typical ocular motor apraxia, but the infant's condition deteriorated 4 months after diagnosis, with the subsequent discovery of a large cystic neoplasma of the rostral brainstem, Recent CT findings8 suggest that hypoplasia of the cerebellar vermis and its brainstem connections may be responsible for the congenital ocular motor apraxia in some cases. Several patients with this syndrome have also been noted to have agenesis of the corpus callosum10. 11 but Slager et al. 13 failed to find any ocular motor dysfunction in their patient or in other reported cases with congenital absence of the corpus callosum. Acquired ocular motor apraxia is seen with disorders that involve saccadic eye movement systems, particularly in a vertical direction. Such an acquired vertical apraxia has been reported in Niemann-Pick disease and its sea-blue histiocyte or OAF variant. 9,14.15it can also be seen in Huntington's chorea, ataxia telangiectasia, Wilson's disease, and other disease stateslO,16 (Table 2). Kernicterus can also cause an acquired ocular motor apraxia,!? but clinical involvement of the basal ganglia and hearing are usually present. Lesions involving bilateral fronto-mesencephalic pathways or bilateral subthalamic and upper brainsteam areas, as in the Roth-Bielschowsky syndrome, I yield various ocular motor apraxias but are also accompanied by other ocular as well as neurologic signs. Bal- TABLE 2. Syndromes Associated with Various Ocular Motor Apraxias inl's syndrome,1U secondary to bilateral parietooccipital lesions, and progressive supranuclear palsy also represent acquired forms of ocular motor apraxia. 1IJ Our patient was born premat~rely a~d experienced significant birth hypOXia ,and Ischemia, which has also been reported In the horizontal form of congenital motor apraxia. I.? His transient perinatal neurologic deficits were felt to be due to this hypoxia and ischemia. Although he did develop hyperbilirubinemia, it responded rather rapidly to phototherapy, and when he was examined at the age of 4.5 years his hearing was normal and he had no evidence of basal ganglion dysfunction. A vertical ocular motor apraxia can be a prominent early finding in storage diseases such as Niemann-Pick and its OAF variant 9 ,IU5 This seems unlikely in our patient, since his abnormality was present from birth, is improving over time, and he has no evidence of hepatosplenomegaly, progressive neurologic disease, or intellectual deterioration. In addition, his identical twin is unaffected, which would argue against it being a genetic disease. While our patient's milestones were normal for his age, he did lag slightly behind his brother. Birth hypoxia was probably responsible for this lag as well as for his gaze disorder. Drs. Buncic and Crawford recently reported a case that was almost identical to ours at the American Association of Pediatric-Ophthalmology and Strabismus Meeting in Puerto Rico in March 1985. CT scanning in that case showed a small hvpolucent area in the left thalamus thought to represent a perinatal infarct. Although our patient's CT scans were normal, such a perinatal infarct seems a plausible explanation ior the apraxia given that the identical twin, who had normal ocular motility and who had also been mildly hypoxic and hyperbilirubinemic, was free of perinatal neurologic problems. In considering the differential diagnosis (Table 3) in a child with apraxia of gaze on a congenital basis (before the development of head thrusts) it is helpful to recall that this is a normal, transient state in some neonates. 18,19 TAULE I Congenital Ocular Motor Apraxia l'\lllll1lillll" .''''~(ld.'ll·d lil\llinh~ Dt'I,II't'd nl<llor dt'Vt'lopllll'nl ('lulllsi,ll'ss, .11.l,i.1 Norlll.,1 inlL'll<'ct Rl,.ldill~ pmbl<'llls 1.<:,-;.-; In'qlH..'nlly rt'p{lrlt'd .I ....snei.'ll'd Iindill)!,:-' (;l'sl.,liull.11 insulls Wl'bbilll'. uf lues (Ihrt't' (t1Sl'S) Immunul'.lobulin A dl'ficiency (unt' casl') Esolropid, exolmpid. hypnlropia Al'.enesis "f the corpus c.ll1osum HamMtoma of foramen of Munro Occipilal purencephalic cyst Medulloblasloma Cleft palale Oral-facial-digital syndrome Me~lal relardalion (four cases) Huntington's chorea Neimann-Pick disease Caucher's disease Central nervous system neoplasms Spinocerebellar degt>neration Ataxia telangectasia Multiple sclerosis Wilson's disease Central nervous system infarctions Olivopontocerebellar degeneration 156 Journal of Clinical Neuro-ophthalmology TABLE 3. Differential Diagnosis of Congenital Ocul.u Motor Apraxia in Infants and Children \'isillil Palsil's llt (l)llillg~lt..• g~l/l' 3. P"l'lIlhH'phth.llm,'pl,'gi.l -!. Sacc.ldic di",'r,it'rs .1ssl1ci.ltl'd with sp,'cilic ~Vndrl)n..,t.·s llr it'Sill!1S Assessment llf visual acuity in preverbal children is dept'ndent lln motlH rt'Spl111St'S. Gittinger and Sllkl)l~tl h,1\'e 1,1bt'1ed such delayed maturation infants ,1S "slow to see." ThuS: in the presence of an inability tll establish fixation or following n1l1\'ements and with a normal funduscopic e'amination, Leber's (Lmgenital amaurosis, cortical blindness, and congenital ocular motor apra'ia are the major considerations. The pattern-reversal visual evoked response and electroretinogram are valuable aids in distinguishing these entities because these tests are relatively independent of abnormalities in the motor system. If a normal visual-evoked response and electroretinogram are present, the diagnosis is most probably congenital ocular motor apraxia.~o In the older child, one must differentiate between simple palsies of conjugate gaze, in which random movements are lost to a greater extent than voluntary movements, and other forms of congenital pseudo-ophthalmoplegia, in which vertical movements are predominantlY affected and in which other neurologic symptoms are prominent. Uo Summary The case of a 41/2-year-old boy with congenital vertical ocular motor apraxia who was otherwise developmentally and neurologically normal was described. The presence of perinatal hypoxia in this and other patients with congenital ocular motor apraxia may be etiologic in some cases. That there was an unaffected identical twin suggested that a hereditary basis for the syndrome was unlikely. Vertical ocular motor apraxia, which usually indicates a serious, acquired neurologic or systemic disease, can occur as an isolated congenital finding that improves with age. Acknowledgment This study was supported in part by a grant from the Society to Prevent Blindness. September 1985 Hughes et al. References 1. Cogan, D. C.: A type of congenital motor apraxia prl'sl'nling jerky head movements. Trans. Am. 1It't1l1. Ophtlmllliol. Oto/al'l/II,I;o/. 56: 853-862, 1952. ") Reed, J. D., and Israelis, S.: Congenital ocular motor ,lpraxia. Hr. f. OphtI1l1/lI/o!. 40: 444-448, 1%6. .1. Riopel, D. A.: Congenital ocular motor apraxia. 11111. I. Ophtha/II/o/. 55: 511-514, 1963. 4. Lyle, D. J.: A discussion of ucular motor apraxia with a case presentation. TrailS. Am. Ophtha/mo/. Soc. 59: 274-285, 1961. 5. Godel, Y., Nemet, r., and Lazar, M.: Cungenital ocular motor apraxia-familial occurence. Optha/ II/%gica 179: 90-93, 1979. 6. Robles, J.: Congenital ocular motor apraxia in identical twins. Arch. Ophthalmol. 75: 746-749, 1966. 7. Cogan, D. G.: Cungenital ocular motor apraxia. Call. f. Optha/I/IO/. 1: 253-260, 1966. 8. Eda, I., Takashima, S., Kitahara, T., Ohno, K., and Takeshita, K.: Computed tomography in congenital ocular motor apraxia. Neuroradi%gy 26: 359-362, 1984. 9. Wybar, K.: Disorders of ocular motility in brain stem lesions in children. AIIII. Oplltlll1/1I10l. 3: 645662, 1971. 10. Miller, N. R.: Walsll alld Hoyt's Clillica/ NCI/ro-ophthaill/% gy (4th ed.), vol. 2. Williams & Wilkins, Baltimore, 1984, pp. 722-732. 11. Orrison, W. W., and Robertson, W. C, Jr.: Congenital ocular motor apraxia: a possible disconnection sYndrome. Arch. NCl/roi. 36: 29-31, 1979. 12. Zaret, C 'R., Behrens, M. M., and Eggers, H. M.: Congenital ocular motor apraxia and brainstem tumor. Arch. Optha/II/o/. 98: 328-330, 1980. 13. Slager, U. T., Kelly, A. B., and Wagner, J. A.: Congenital absence of the corpus callosum: report of a case in review of the literature. N. EllSI. 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