Signs distinguishing spasmus nutans (with and without central nervous system lesions) from infantile nystagmus

Measurement of visual function in infantile nystagmus: a systematic review

BACKGROUND/AIMS

Recent work has called into question the ability of visual acuity (VA) to accurately represent changes in visual function in infantile nystagmus (IN). This systematic review investigated factors affecting visual performance in IN, to guide development of suitable alternatives to VA.

METHODS

Included studies used an experimental manipulation to assess changes in visual function in people with IN. Interventional studies, case series and case studies were excluded. Six databases were searched in August 2023. Selection, detection, attrition and measurement bias were assessed. Due to heterogeneous methodologies, narrative synthesis was undertaken.

RESULTS

Eighteen relevant papers were identified, 11 of which complied with the review criteria. Articles were grouped according to the factor manipulated to evoke within-participant changes in performance (motion blur, psychological state, gaze angle or visual crowding). Optotype, image, grating and moving stimuli have been employed under varying lighting conditions and exposure duration.

CONCLUSION

Several factors affecting visual performance should be considered when assessing visual function in IN. While maximum VA is a useful metric, its measurement deliberately minimises nystagmus-specific factors such as changes in visual performance with gaze angle and the 'slow to see' phenomenon. Maximum VA can be measured using the null zone, providing unlimited viewing time, reducing stress/mental load and minimising visual crowding. Gaze-dependent functional vision space is a promising measure which quantifies the impact of the null zone but does not consider temporal vision. Although no complete measurement technique has yet been proven, this review provides insights to guide future work towards development of appropriate methods.

Infantile nystagmus syndrome: An observational, retrospective, multicenter study

SIGNIFICANCE

This multicenter study assessed clinical and psychological aspects of infantile nystagmus syndrome (INS) focusing on its management and nonsurgical treatment.

PURPOSE

This study aimed to assess clinical features, management, relationship life, and psychological impact in a group of patients with nystagmus onset in pediatric age.

METHODS

This observational study included patients diagnosed with INS referred to two Italian centers from January 1, 2017, to December 31, 2020. Ophthalmologic and orthoptic features and impact of visual function on quality of life, according to nystagmus-specific nystagmus quality of life questionnaire, were analyzed within the overall sample and in any of INS subgroups.

RESULTS

Forty-three patients were included; 65.1% of them had idiopathic INS (IINS), and 34.9% had INS associated with ocular diseases (INSOD). The median age was 15.4 years (interquartile range [IQR], 10.4 to 17.3 years), significantly different between groups (median, 15.8 years among those with IINS vs. 12.3 years among those with INSOD; p<0.001). In the INSOD subgroup, strabismus was significantly more prevalent (93.3 vs. 57.1%; p=0.017). Binocular distance best-corrected visual acuity in primary position was significantly higher in the IINS subsample (p<0.001). Such behavior was further confirmed at anomalous head position evaluation (p<0.001). At near best-corrected visual acuity assessment, differences between groups were more remarkable in primary position (p<0.001) than in anomalous head position. Contrast sensitivity showed significantly higher values in the IINS subgroup (p<0.001). The nystagmus quality of life questionnaire disclosed a significantly lower score in IINS as compared with INSOD (median total score, 90.5 [IQR, 84 to 97] vs. 94 [IQR, 83.0 to 96.5]; p<0.001).

CONCLUSIONS

The IINS group showed significantly better ophthalmologic and orthoptic outcomes than the INSOD group. The psychological and quality-of-life impact was instead significantly greater in the IINS group. To the best of our knowledge, this is the first multicenter study investigating the clinical features of IIN and comparing the two main subgroups, IINS and INSOD.

Eyetracking-enhanced VEP for nystagmus

Visual evoked potentials (VEPs) are an important prognostic indicator of visual ability in patients with nystagmus. However, VEP testing requires stable fixation, which is impossible with nystagmus. Fixation instability reduces VEP amplitude, and VEP reliability is therefore low in this important patient group. We investigated whether VEP amplitude can be increased using an eye tracker by triggering acquisition only during slow periods of the waveform. Data were collected from 10 individuals with early-onset nystagmus. VEP was obtained under continuous (standard) acquisition, or triggered during periods of low eye velocity, as detected by an eye tracker. VEP amplitude was compared using Bonferroni corrected paired samples t-tests. VEP amplitude is significantly increased when triggered during low eye velocity (95% CI 1.42-6.83 µV, t(15) = 3.25, p = 0.0053). This study provides proof-of-concept that VEP amplitude (and therefore prognostic reliability) can be increased in patients with early onset nystagmus by connecting an eye tracker and triggering acquisition during periods of lower eye velocity.

Eye oscilations with neurological implications in pediatric age

INTRODUCTION

Eye oscillations, both nystagmic and non-nystagic, can occur from birth. Most correspond to infantile nystagmus that dubates in the first six months of life, which include idiopathic, sensory, latent, or overt latent motor nystagmus. Those associated with neurological diseases or syndromes correspond to approximately 33%, their identification and correct evaluation being important given the potential visual and vital complications.

MATERIAL AND METHODS

We made a systematic review of the literature on supranuclear gaze control mechanisms and the main ocular oscillations with possible neurological implications, both in childhood. With this, we intend to assess if there are already established clinical-anatomical associations, and to propose a protocol on the complementary studies to be carried out in these cases.

RESULTS

There are still anatomical pathways involved in supranuclear gaze control that are not fully clarified and understood. Besides, except in the case of nystagmus in seesaw and upbeat, we did not find anatomical explanations for their pathogenesis. The need for complete neuro-ophthalmological physical examinations and the request for additional tests in children who present ocular oscillations with neurological characteristics are clear.

CONCLUSIONS

Supranuclear gaze control follows a complex neurological network that still needs to be studied better. With a better dissection of the same we could try to understand why the ocular oscillations that we studied have these specific forms of presentation. As for the complementary requests, the request for neuroimaging tests is practically constant, making the others according to the specific case before which we find ourselves.

Management of nystagmus in children: a review of the literature and current practice in UK specialist services

Nystagmus is an eye movement disorder characterised by abnormal, involuntary rhythmic oscillations of one or both eyes, initiated by a slow phase. It is not uncommon in the UK and regularly seen in paediatric ophthalmology and adult general/strabismus clinics. In some cases, it occurs in isolation, and in others, it occurs as part of a multisystem disorder, severe visual impairment or neurological disorder. Similarly, in some cases, visual acuity can be normal and in others can be severely degraded. Furthermore, the impact on vision goes well beyond static acuity alone, is rarely measured and may vary on a minute-to-minute, day-to-day or month-to-month basis. For these reasons, management of children with nystagmus in the UK is varied, and patients report hugely different experiences and investigations. In this review, we hope to shine a light on the current management of children with nystagmus across five specialist centres in the UK in order to present, for the first time, a consensus on investigation and clinical management.

Visual Behaviors and Adaptations Associated with Cortical and Ocular Impairment in Children

Visual loss leads to visual behaviors and adaptations that tend to reflect the onset, severity, and types of visual impairment. In this article, the characteristic behaviors associated with different degrees of visual loss and their importance in the diagnosis of cortical versus ocular visual impairment are discussed.

Visual Function, Brain Imaging, and Physiological Factors in Children With Asymmetric Nystagmus due to Chiasmal Gliomas

PURPOSE

Asymmetric nystagmus can be an important presenting sign of optic pathway gliomas in young children. We investigated the causes of asymmetric nystagmus in children with chiasmal or suprasellar optic pathway gliomas compared with children with similar optic pathway gliomas and stable gaze.

METHODS

Longitudinal magnetic resonance imaging before and after treatment, age-corrected visual acuity, ocular examinations, video-oculography, visual evoked potentials, and retinal nerve fiber layer thickness were retrospectively reviewed.

RESULTS

Twenty-two children were included (eight with asymmetric nystagmus and 14 with stable gaze). Subjects with asymmetric nystagmus presented at a younger age than those with stable gaze (2.0 vs 5.6 years; P < 0.001). None had neurofibromatosis type 1. Visual acuity, visual evoked potentials, nerve fiber layer, severity of optic atrophy, hydrocephalus, tumor volume, and tumor locations did not differ between those with asymmetric nystagmus and stable gaze. Asymmetric nystagmus resolved shortly after treatment, even though the average visual acuity did not improve. Changes in visual acuity or tumor volume were not different between those with asymmetric nystagmus and stable gaze after treatment. Eye movement recording from two subjects with asymmetric nystagmus revealed an asymmetric pendular-oscillation with vertical components. One subject with stable gaze developed asymmetric nystagmus with tumor growth into the rostral midbrain and associated unilateral vision loss. Another subject with tumor growth into the rostral midbrain acquired vertical saccade dysmetria.

CONCLUSION

We hypothesize that asymmetric nystagmus associated with optic pathway gliomas is caused by subclinical abnormalities to retinal axons that connect to gaze holding centers in the rostral midbrain. Direct compression of the rostral midbrain was a possible factor to asymmetric nystagmus in some subjects. However, many subjects with stable gaze also show midbrain compression.

Acquired monocular nystagmus in chiasmal glioma-a video-oculographic study

We report the case of a 9-year-old girl with chiasmal glioma and longstanding monocular nystagmus, in whom video-oculography showed a disconjugate binocular nystagmus indistinguishable from spasmus nutans. The "acquired monocular nystagmus" associated with chiasmal glioma is actually a binocular nystagmus that is indistinguishable from spasmus nutans, except that it lacks the associated head nodding and torticollis. Superimposed visual loss in one eye predisposes to acquired monocular nystagmus and explains the absence of the other components of the spasmus nutans triad.

Long-Term Follow-up of Spasmus Nutans

PURPOSE

Spasmus nutans is an acquired form of nystagmus that is classically associated with torticollis and titubations of the head, often presenting in the first year of life and spontaneously resolving within the next 2 years. The purpose of our study was to record and characterize the long-term prognosis of children diagnosed with spasmus nutans.

METHODS

All patients under the age of 21 years with a diagnosis of spasmus nutans were included. Parameters of age, nystagmus symmetry and quality, presence of titubations, torticollis, and strabismus, and findings on CT or MRI were recorded.

RESULTS

Our 22 patients had an average age of onset of 9.8 and a follow-up of 62.6 months. Nystagmus was unilateral in 5 children, asymmetric in 5, symmetric in 10, and inapparent in 2. Titubations were identified in 10 and torticollis in 7. Nystagmus persisted in 16 of 20 children, titubations in 3, and torticollis in 6. Neuroimaging, performed on 17 of the 22 children, was negative for any space-occupying lesions.

CONCLUSION

In conclusion, we are reluctant to assure parents of children who have even the most typical spasmus nutans that their child will be normal after a predictable interval. Instead, we advise them that many children do well, assuming normal imaging, but that nystagmus, torticollis, and even titubations may persist. Follow-up, especially for strabismus and amblyopia, should be continued throughout childhood.

Infantile and acquired nystagmus in childhood

Nystagmus is an involuntary, periodic eye movement caused by a slow drift of fixation which is followed by a fast refixation saccade (jerk nystagmus) or a slow movement back to fixation (pendular nystagmus). In childhood most cases are benign forms of nystagmus: idiopathic infantile, ocular or latent nystagmus. They arise at the age of 3 months, without oscillopsia and show the absence of the physiologic opto-kinetic nystagmus. A full ophthalmologic evaluation is all that is needed in most cases: albinism, macular or optic nerve hypoplasia and congenital retinal dystrophies are the most common forms of ocular nystagmus. Idiopathic infantile nystagmus can be hereditary, the most common and best analyzed form being a mutation of the FRMD7 gene on chromosome Xq26.2. The mutation shows a mild genotype-phenotype correlation. In all female carriers the opto-kinetic nystagmus is absent and half had mild nystagmus. Latent nystagmus is part of the infantile esotropia syndrome and shows the unique feature of change of direction when the fixing eye changes: it is always beating to the side of the fixing eye. There is no cure for infantile nystagmus but therapeutic options include magnifying visual aids or eye muscle surgery at the age of 6-8 y in patients with head turn. Less than 20% of childhood nystagmus are acquired and need further neurological and imaging work-up. Alarming signs and symptoms are: onset after the age of 4 months, oscillopsia, dissociated (asymmetric) nystagmus, preserved opto-kinetic nystagmus, afferent pupillary defect, papilloedema and neurological symptoms like vertigo and nausea. The most common cause is due to pathology of the anterior optic pathway (e.g. optic nerve gliomas). It shows the same clinical feature of dissociated nystagmus as spasmus nutans but has a higher frequency as in INO. Other forms of acquired nystagmus are due to brainstem, cerebellar or metabolic diseases.

Epidemiology and management of essential tremor in children

Essential tremor (ET) is a common, often familial, movement disorder characterized by tremor of the limbs, head, and voice. Epidemiological surveys indicate that up to 5% of the adult population has ET, and 5-30% of adults with ET report symptom onset during childhood. There is, however, little published regarding ET in the pediatric population, and no prospective studies targeted specifically to children. Retrospective studies from subspecialty movement disorder clinics indicate that childhood-onset ET is usually hereditary, begins at a mean age of 6 years, and affects boys three times as often as girls. While ET occasionally results in disability during childhood, only one-quarter of children seeing a neurologist for ET require pharmacotherapy. Small case series suggest that propranolol is effective in approximately 50% of children with ET, but controlled treatment trials are lacking.

Tremor in childhood

Tremor in childhood is not commonly described in the literature; but it is also likely underappreciated. The etiology of childhood tremor encompasses a wide variety of pathologic processes. Tremor may occur in isolation, or in association with other neurologic findings or systemic disorders. This article aims to provide an overview of tremorogenic mechanisms with respect to neuroanatomy and neurophysiology, particularly as they relate to children. Classification of tremors, diagnostic entities in childhood, and treatment will also be discussed. With improved recognition and characterization of childhood tremors, we may gain a better understanding of the pathophysiology of the disease and determine more age-appropriate treatment strategies.

Spasmus Nutans-Like Nystagmus is Often Associated With Underlying Ocular, Intracranial, or Systemic Abnormalities

BACKGROUND

There is uncertainty as to whether spasmus nutans (SN) is an isolated idiopathic entity or whether there are underlying conditions that could cause or be associated with the nystagmus. We undertook this study to determine the frequency of ocular, intracranial, and systemic conditions in patients with nystagmus having characteristics of SN.

METHODS

We performed a chart review of 22 consecutive patients examined from 2000 through 2005 at the Dean McGee Eye Institute and Children' Hospital of Oklahoma with nystagmus consistent with SN. We collected information related to gender, age at presentation and age at final visit, visual acuity, refractive error, laterality of nystagmus, presence of head nodding and torticollis, pattern of strabismus, neuroimaging and electroretinography results, and other associated clinical findings.

RESULTS

Visual acuity was reduced in 75% of eyes at presentation and 58% of eyes at last visit. Eight patients had significant refractive error. Seven patients had strabismus. Two patients had chiasmal gliomas. Four patients had cone or rod/cone dystrophy. Only three patients had no associated ocular, intracranial, or systemic conditions.

CONCLUSIONS

A substantial proportion of patients presenting with SN-like nystagmus have important underlying ocular, intracranial, or systemic abnormalities that may require evaluation and management.

Paroxysmal nonepileptic events of childhood

The paroxysmal nonepileptic events of childhood are a group of disorders, syndromes, and phenomena that mimic true epileptic seizures. Clinical experience and a clear description of the event in question will usually lead to a correct categorization. They span in age from neonate to young adult and are apt to be the most common diagnostic challenges clinicians face regularly. The key to diagnosis is a detailed history and careful observation. Despite the large number of discrete entities enumerated herein, common principles in clinical approach are successful and described. Each entity can pose a significant clinical challenge in identification, etiologic pathophysiology, genetics, and management. A simple division is offered here separating those episodes that are associated with an altered mental status or occurring during sleep and those without an altered mental status or occurring while awake.

Medical Imaging in Pediatric Neuro-Ophthalmology

This article provides an outline of the congenital and acquired conditions encountered in the practice of pediatric neuro-ophthalmology. Although some entities can be effectively evaluated clinically, CT and MR imaging studies may prove instrumental in many instances for detailed evaluation, narrowing of the differential diagnosis, or exclusion of underlying central nervous system pathologic findings.

Infantile-onset nystagmus

PURPOSE OF REVIEW

Recent studies on the various forms of infantile-onset nystagmus have advanced our understanding of these disorders. The previously described waveforms of infantile nystagmus syndrome (congenital nystagmus) may be identified in infants less than 7 months of age, including the more mature forms; the visual status of these patients may be directly correlated with their mean foveation times.

RECENT FINDINGS

Refractive errors in patients with infantile nystagmus syndrome do not follow the expected trend toward emmetropization during infancy and early childhood. A study on the torsional component of nystagmus present in most patients with infantile nystagmus syndrome found it to be generated centrally and not by peripheral or mechanical dynamics. Two psychophysical studies on patients with infantile nystagmus syndrome revealed significant differences compared with control subjects. Two different animal models imply that lack of normal visual motion during a critical period of development in infancy leads to infantile nystagmus syndrome. An electron microscopic study of the enthesis site-where the extraocular muscle tendon inserts onto the sclera-in normal individuals versus patients with infantile nystagmus syndrome revealed significant abnormalities in the latter. Significant demographic and socioeconomic differences were reported between patients with infantile nystagmus syndrome and those with spasmus nutans.

SUMMARY

New evidence supports a role for sympathomimetic modulation of infantile nystagmus syndrome. Novel surgical treatments for infantile nystagmus syndrome are also discussed.

A comparative demographicand socioeconomic study of spasmus nutans and infantile nystagmus

PURPOSE

To compare the demographic and socioeconomic background of patients with spasmus nutans (SN) and patients with idiopathic infantile nystagmus (IIN).

METHODS

This study was performed according to an observational case-control design. Parents or guardians of 23 patients with SN and 24 patients with IIN completed a 28-point questionnaire on demographic, socioeconomic, behavioral, personal, and family history. Mann-Whitney U tests were used to compare continuous dependents and chi(2) analyses for categorical variables. Correlation between variables was calculated by Spearman rho tests and odds ratios for SN by Mantel-Haenszel estimates.

RESULTS

Comparing SN and IIN, Afro-American, and Hispanic ethnicity was significantly more common in SN (14 patients, 61%) than in IIN (1 patient, 4%). Significant differences between the groups were also found for gestational age (mean SN: 37.7 weeks, IIN: 40.3 weeks), home luminance at birth was reported to be brighter in more IIN patients (22 patients, 96%) as compared with the SN patients (15 patients, 71%). Factors reflecting a lower socioeconomic status were more prevalent in SN patients (annual household income, individual financially responsible for the household, source of income, availability of private medical insurance). In the SN group there were fewer married parents living together (9 families, 39%) than in the IIN group (21 families, 88%). Psychiatric disorders, including alcohol and drug abuse, were more frequent among parents of SN (10 parents, 47%) than of IIN (none). Annual household income and ethnicity correlated significantly with number of rooms/household.

CONCLUSION

This study demonstrated differences between SN and IIN patients and their families with regard to socioeconomic status, ethnicity, gestational age, psychiatric diseases of parents, and parental estimation of light exposure early in life. We conclude that low socioeconomic status represents a risk factor for the development of SN.

Nystagmus

This report reviews the recent contributions to the field of pathologic nystagmus. The classification and nomenclature of nystagmus with onset in infancy is controversial. Because there are differences in nystagmus forms between patients with idiopathic nystagmus and those with nystagmus associated with afferent sensory defects, a distinction between these two nystagmus types is proposed. The distinctions are also helpful for clinicians, because these separate entities imply different diagnostic evaluations and visual prognosis. Recent studies have confirmed that periodic alternating nystagmus is detected more easily if the patient is evaluated for a longer time period and occurs more commonly than previously thought. Psychophysical investigations indicate that extraretinal signals play an important role in suppression of oscillopsia in infantile nystagmus. Genetic analysis recently has allowed identification of genes of X-linked idiopathic nystagmus and achromatopsia.

Electroretinography is necessary for spasmus nutans diagnosis

The purpose of the present study was to determine whether that which clinically appeared to be spasmus nutans could actually represent retinal sensory deficits diagnosable by electroretinography. Eight patients clinically thought to have spasmus nutans underwent electroretinography according to international standards. Five had normal electroretinograms and represented cases of true spasmus nutans. Three patients had abnormal electroretinograms, indicating that they did not have spasmus nutans. The clinical findings used to diagnose spasmus nutans can be simulated by retinal dystrophies. A normal electroretinogram is needed to confirm the diagnosis of spasmus nutans.

Vertical or asymmetric nystagmus need not imply neurological disease

AIM

To indicate that congenital idiopathic nystagmus (CIN) and sensory defect nystagmus (SDN) can be vertical or asymmetric in some children.

METHODS

Of 276 children presenting with nystagmus for electrophysiological testing, 14 were identified as having CIN or SDN, yet had a nystagmus which was either vertical (n=11) or horizontal asymmetric (n=3). Flash electroretinograms and flash and pattern visual evoked potentials (VEPs) were recorded in all patients. Eye movement assessment, including horizontal optokinetic nystagmus (OKN) testing, was carried out in 11/14 patients.

RESULTS

Eight patients (seven with vertical, one with asymmetric horizontal nystagmus) had congenital cone dysfunction. One patient with vertical and another with asymmetric nystagmus had cone-rod dystrophy. One patient with vertical upbeat had congenital stationary night blindness. Two patients (one downbeat, one upbeat nystagmus) had normal electrophysiological, clinical, and brain magnetic resonance imaging findings and were classified as having CIN. One patient with asymmetric nystagmus showed electrophysiological and clinical findings associated with albinism. Horizontal OKN was present in 80% of patients tested, including the three cases with horizontal asymmetric nystagmus. This is atypical in both CIN and SDN, where the OKN is usually absent.

CONCLUSIONS

Vertical and asymmetric nystagmus are most commonly associated with serious intracranial pathology and its presence is an indication for neuroimaging studies. However, such nystagmus can occur in children with retinal disease, albinism, and in cases with CIN. These findings stress the importance of non-invasive VEP/ERG testing in all cases of typical and also atypical nystagmus.

Childhood head tremor

We report here four children (three girls, one boy) with head tremor followed longitudinally, ages 15 months to 11 years, with follow-up over 1 to 8 years. Each demonstrated onset of head tremor between the ages of 5 and 10 months. In each case head tremor was characterized by a predominant "yes-yes" or "no-no" movement of the head. In two of the children the movement was slightly skewed with chin movement toward the shoulder. Oscillations were at a frequency of about 1 to 2 Hz. They were accentuated when sitting upright without head support, increased at times of movement, and dissipated while lying flat or sleeping. The children were unable to voluntarily suppress the action and did not experience any sensation of movement. Three of the children had shuddering spells prior to onset of head tremor. Two children have developed mild dystonic posturing of the legs when intently concentrating. Their general and neurologic examinations were normal. Normal investigations included brain magnetic resonance imaging and computed tomography, urine amino acids and organic acids screening, serum lactate, erythrocyte sedimentation rate, antinuclear antibodies, and ceruloplasmin and copper levels. A family history of tremor was present in two children, maternal epilepsy in one child, and infantile shuddering occurred in the father of one child. Therapy included trials of selective and nonselective beta-adrenergic blockers, alpha-adrenergic agonists, anticholinergics, anticonvulsants, and amantadine. One child responded well to both timolol and trihexyphenidyl. A second child responded moderately to primidone. Two have not been treated. Two have had head tremor spontaneously remit. We conclude from this small series of children with head tremor that it can evolve from a prior history of shuddering spells, occurs in the context of a positive family history of tremor, and can be accompanied by the development of a mild dystonia. Therapeutic response is variable to multiple agents. Spontaneous remission occurs, suggesting a benign course.

Nystagmus mimicking spasmus nutans as the presenting sign of Bardet-Biedl syndrome

PURPOSE

To investigate the nystagmus of twin brothers presenting with spasmus nutans later diagnosed as Bardet-Biedl syndrome.

METHODS

The twins presented at the age of 14 months with a presumed diagnosis of spasmus nutans. They were followed clinically and with quantitative electro-oculographic eye movement recordings until the age of 6 years.

RESULTS

Polydactyly, truncal obesity, mild delay in cognitive development, visual acuity of 20/100, attenuated retinal vessels and pale disks, and bilaterally almost extinguished scotopic and photopic electroretinograms were found in both brothers. They had fine, fast, pendular, disconjugate, intermittent, oblique nystagmus. No head nodding was observed.

CONCLUSION

As described in patients with other retinal diseases such as achromatopsia and congenital stationary night blindness, nystagmus of patients with Bardet-Biedl syndrome can mimic spasmus nutans.

Transient nystagmus in delayed visual maturation

Two infants who presented with wide-amplitude and high-frequency nystagmus and lack of visual awareness in the first 3 months of life were studied. No ocular abnormalities were found. Neurodevelopmental examination, visual evoked potentials and electroretinograms were normal. One infant underwent MRI which resulted in normal findings. Two months later both patients showed increased visual responsiveness and a gradual reduction of the nystagmus amplitude. By 5 months of age nystagmus was no longer detectable and both infants appeared to be visually, developmentally, and neurologically normal. Follow-up at 3 years of age for subject 1 and at 11 months for subject 2 showed that both the infants maintained the normal ophthalmological and neurological assessments. We diagnosed delayed visual maturation with oculomotor involvement.

[Spasmus nutans: apropos of 16 cases]

Spasmus nutans is a syndrome occurring in early childhood. It consists of a triad of symptoms: head nodding, ocular oscillations and anomalous head position. Ophthalmologic and neurological findings are otherwise normal. This syndrome is benign and has spontaneous resolution.

PATIENTS AND METHOD

Sixteen patients with spasmus nutans seen from 1980 to 1995 were retrospectively studied. Their present status was evaluated by clinical examination or questionnaire.

RESULTS

The age at onset ranged from 1 to 15 months (average 7 months). Thirteen of 16 patients were referred for head nodding, which was a constant manifestation; its direction was horizontal, vertical or rotatory. Nystagmus was present in 14 infants. It was acquired, asymmetrical, bilateral (or unilateral in three cases), rapid, fine, pendular and horizontal. Both head nodding and nystagmus were intermittent. Anomalous head position was present in seven cases, consisting of head tilt or a chin upon/chin down posture. Neuroimaging (13 cases) was always normal. The follow-up in 12 children (up to 2 years) showed a complete resolution of the syndrome in 6 months to 6 years (average 2.5 years).

DISCUSSION

The diagnosis was established by the constancy of the characteristic triad and the elimination of the other causes of nystagmus. Isolated head nodding had to be distinguished from bobble head syndrome. In several reported cases, electronystagmography recordings have suggested that head nodding is a compensatory process against nystagmus and that the head tilt allows transient resolution of the nystagmus.

CONCLUSION

Spasmus nutans is a self-limiting benign clinical entity. Normal complete ophthalmologic and neurological examination, as well as magnetic resonance imaging (MRI) are necessary to confirm the diagnosis.

Costenbader Lecture. Idiopathic infantile nystagmus: diagnosis and treatment

Current concepts of idiopathic infantile nystagmus are summarized, with special attention to treatment and differential diagnosis of this condition. Advantages of the Anderson procedure over the Kestenbaum procedure are suggested for head turn associated with this condition, and the need for further studies is acknowledged. The importance of the extended slow phase in understanding the waveforms of infantile nystagmus is stressed. Our studies reinforce what I believe to be the natural history of infantile nystagmus, as well as the history of periodic alternating nystagmus. The critical delineation of diagnosing periodic alternating nystagmus is emphasized with respect to the type of operation to avoid overcorrection of head turns in patients with nystagmus. Continued searches for manifest latent nystagmus are important, because that condition is currently the only truly treatable nystagmus. I thank the American Association for Pediatric Ophthalmology and Strabismus for the privilege and honor of presenting the 1997 Costenbader Lecture.

The association of strabismus, amblyopia, and refractive errors in spasmus nutans

PURPOSE

Spasmus nutans is a condition that includes asymmetric nystagmus and occurs during the amblyogenic period. Because specific alterations in early visual experience are known to be associated with changes in visual development, relations between spasmus nutans and abnormal visual sequelae were examined.

METHODS

The records of 18 patients with spasmus nutans were reviewed retrospectively. The incidence of strabismus, amblyopia, anisometropia, and astigmatism was compared with published age-matched control subjects.

RESULTS

There was a significantly higher incidence of strabismus (10 of 18) and amblyopia (8 of 18) of the eye with the greater amplitude of nystagmus. No correlation of refractive error with lateralization of nystagmus could be established. Twelve of 18 patients required spectacles for improvement in visual acuity and for treatment of amblyopia. Best-corrected visual acuity averaged 1.20 Snellen lines poorer than age-adjusted normative values; however, loss of visual acuity was, in most cases, symmetric and not related to lateralization of nystagmus.

CONCLUSION

Early detection and treatment of anticipated abnormal visual issues in patients with spasmus nutans will optimize visual outcomes.

Prevalence of intracranial lesions in children initially diagnosed with disconjugate nystagmus (spasmus nutans)

A small number of children who develop disconjugate nystagmus, torticollis, and head titubation (spasmus nutans) have been found to have optic chiasm or third ventricle gliomas. However, the prevalence of glioma or other developmental abnormalities in this disorder is unknown because no large series of spasmus nutans cases has previously been reported. A reviewer of the records of 67 consecutive children initially diagnosed with spasmus nutans and followed for an average of 3.3 years at the St Louis Children's Hospital revealed the following: 61% had a history of prematurity, developmental delay, or other systemic abnormality; strabismus, most commonly infantile esotropia, developed in 55%; 43% had neuroimaging studies; and 0% had evidence of a glioma or showed signs of tumor on follow-up examinations. From this consecutive patient series, we estimate the prevalence of tumor in spasmus nutans to be less than 1.4%. Without other evidence of an intracranial mass lesion, neuroimaging of infants initially diagnosed with spasmus nutans may not be immediately warranted.

Quantitative eye and head movement recordings of retinal disease mimicking spasmus nutans

PURPOSE/METHODS

To investigate whether quantitative head and eye movement recordings can distinguish patients with spasmus nutans from patients with retinal diseases mimicking spasmus nutans. A patient with congenital stationary night blindness was followed up for seven years with electro-oculographic eye movement recordings.

RESULTS/CONCLUSIONS

Rhythmic head movements and fine, intermittent, asymmetric, disconjugate, high-frequency, out-of-phase pendular nystagmus were recorded. Eye and head movement recordings of patients with congenital stationary night blindness can mimic spasmus nutans.

Eye and head movements in patients with achromatopsia

The diagnosis of patients with rod monochromatism (RM) and blue-cone monochromatism (BCM) may be difficult. The relative direction and symmetry of nystagmus of the two eyes, as well as the existence or nature of rhythmic head movements, are not known. We analyzed simultaneous eye and head movement recordings of 16 patients with RM and three patients with BCM. Longitudinal examinations were performed in seven patients. Younger patients had pendular, intermittent or continuous oblique nystagmus with both eyes oscillating in phase or out of phase with equal amplitudes. Older patients had continuous symmetrical oblique jerk nystagmus with decreasing velocities in the slow phase. In two children, we demonstrated evolution from pendular to predominantly jerk nystagmus. Rhythmic head movements were detected in all children. Patients with RM and BCM exhibit a distinct entity of nystagmus and can be differentiated from patients with congenital or latent nystagmus. However, eye and head movements can mimic spasmus nutans.

Monocular nystagmus caused by unilateral anterior visual-pathway disease

The authors examined five young children with monocular vision loss who developed monocular nystagmus. The nystagmus was of fast frequency and small amplitude in all fields of gaze. In four children, successful treatment of the cause of the vision loss resulted in cessation of the nystagmus. No child showed signs of spasmus nutans, or of optic nerve or chiasmal tumor. The evaluation of the young child with unilateral nystagmus should begin with a careful eye examination.

Common pediatric neuro-ophthalmologic conditions

Neuro-ophthalmologic problems are some of the most distressing ocular conditions to affect children. In this article the author discusses the differential diagnosis and management of blindness during the first year of life. Nystagmus or 'jiggling eyes' tumors of the visual pathways and acquired ocular motor neuropathies comprise the balance of the article.

Head nodding is compensatory in spasmus nutans

BACKGROUND

Spasmus nutans is defined as asymmetric nystagmus with associated head nodding in childhood. It is not clear whether head nodding is a compensatory mechanism to control the nystagmus or an involuntary movement of pathologic origin.

METHODS

The authors analyzed the relation between head and eye movements by simultaneous eye and head movement recordings of 35 patients with spasmus nutans.

RESULTS

In 21 of these patients, the fine, fast, dissociated nystagmus changed during head nodding to larger and slower symmetric eye movements with both eyes oscillating at the same amplitude in phase and 180 degrees out of phase to the head movements, corresponding to a normal compensatory vestibulo-ocular reflex.

CONCLUSION

These findings indicate that head nodding is compensatory in spasmus nutans.