The Ophthalmologist’s Role in Visual Processing and Learning Disabilities



The Ophthalmologist’s Role in Visual Processing and Learning Disabilities


Harold P. Koller

Kenneth B. Goldberg



SYSTEMIC CONDITIONS THAT MAY AFFECT READING AND LEARNING

Many systemic conditions can be responsible for temporary or chronic visual disturbances in the classroom that can impact performance and reading efficiency. Learning in the long term, however, is not affected. Children with chronic allergies that cause tearing, itching, redness, and burning often have these annoying symptoms during class. Appropriate treatment is readily available with antihistaminic eye drops. Other systemic conditions such as juvenile rheumatoid arthritis, chronic sinusitis, and ocular trauma all, at one time or another, can result in some visual discomfort and make reading a bit stressful (usually leading to frustration or reduction in reading rate or fluency). They never interfere with learning or cerebral processing function and can once again be compensated for with accommodations (i.e., increasing time for reading, books on tape, having a “note-taking” service for class).1

Other disorders affecting learning that an ophthalmologist frequently sees include Tourette syndrome and other developmental neurologic conditions (i.e., cerebral palsy). Idiopathic sleep disorders can also affect learning, as can social and family dysfunction or poor school instruction. Several serious genetic diseases are frequently associated with learning disorders. These include familial dysautonomia (Reilly-Day syndrome2) and mitochondrial cytopathy.3 Both of these conditions involve multiple organ systems. The brain is a high oxygen/energy uptake organ system, and the mitochondria are the oxygen generators of our cells. Any disease of the mitochondria affects most organ systems. The autonomic nervous system is almost nonfunctional in familial dysautonomia, and brain processing is also affected. Much more research regarding mitochondrial (not nuclear) inheritance is required to associate learning disorders with these conditions. Familial dysautonomia may also be a partial mitochondrial disorder, as might certain types of learning disorders.


OCULAR CONDITIONS AFFECTING READING

Koller has described a number of purely ophthalmic conditions that at times may affect reading efficiency and attention (Table 42.1).4 All of them do not, however, permanently influence learning. These conditions include strabismus, amblyopia, nystagmus, pituitary disorders, infections (such as herpes simplex), trauma, and various congenital anomalies of the anterior and posterior ocular segments. Convergence insufficiency exophoria/tropia may cause reading fatigue, but never has been shown to cause a learning disorder. The other conditions may make seeing a bit more difficult and create a need for more testing time and/or visual aids, but they do not directly or indirectly affect comprehension and learning. Intermittent blurring can occur with any of these conditions. Individuals with Disabilities Education Act (IDEA) and help with Individual Educational Plans are available to such students, if only for the period their ocular symptoms are active. This of course may be permanent in a number of cases (i.e., albinism, optic atrophy). Orthoptic eye exercises may be of benefit for individuals with true convergence insufficiency to alleviate their reading fatigue by creating diplopia awareness and improving convergence amplitudes.


MIGRAINE

Migraine has been defined as “a familial disorder characterized by recurrent attacks of headache of variable frequency, duration, and intensity, which are usually unilateral and associated with anorexia, nausea, and vomiting, the attacks may be preceded or accompanied by neurologic or visual symptoms.”5 The 28th edition of Dorland’s Illustrated Medical Dictionary defines migraine as “an often familial symptom complex of periodic attacks of vascular headache, usually temporal and unilateral in onset, commonly associated with irritability, nausea, vomiting, constipation, or diarrhea, and often photophobia. Attacks are preceded by constriction of the cranial arteries, often with resultant prodromal sensory (especially ocular) symptoms and the spreading depression of Leão; the migraines themselves commence with the vasodilation that follows.”6 Migraines can occur without aura in approximately 10% of the population and are responsible for approximately 60% of all types of migraine attacks.7 Classic migraine begins with an aura, whereas common migraine may not. Migraine may also occur without headache. This “acephalgic migraine” variant is more common in children and may consist of any type of aura5 affecting vision alone (Table 42.2).








TABLE 42-1. Visual Perception and Learning Differences in Pediatric Ophthalmology: What the Ophthalmologist Needs to Know about LDs in Clinical Practice

























































































































































































































































































































































































































































I. Ophthalmic Causes of Temporary Learning Impairment and Inefficiency

A. Strabismus, amblyopia, and refractive errors


1. Decompensated accommodative esotropia with secondary diplopia


2. Secondary ocular cranial nerve palsies (n. III, IV, VI)


3. Uncorrected congenital vertical strabismus with abnormal face and head positions


4. Bilateral very high ametropias, such as bilateral amblyopia of high hyperopia


5. Bilateral occlusion amblyopia, such as after congenital cataract surgery


6. Associated untreated “A” and “V” syndromes


7. Convergence insufficiency exotropia/phoria in certain individuals

B. Nystagmus of moderate-to-severe degree causing significant vision loss

C. Pediatric ocular diseases that can affect learning via visual and emotional effects


1. Severe juvenile rheumatoid arthritis and related ocular inflammations


2. Congenital glaucoma with vision loss


3. Congenital cataracts and major corneal opacities with vision loss and nystagmus


4. Significant unilateral and/or bilateral ocular trauma with vision loss


5. Ocular and adnexal neoplasms with secondary disfigurement and vision loss


6. Severe chronic ocular infections such as HSV-I with vision loss


7. Congenital and degenerative retinal diseases affecting the macula


II. Neuro-Ophthalmic Causes of Temporary or Intermittent Learning Impairment and Inefficiency

A. Brain tumors causing a change in personality and behavior in a pediatric patient

B. Migraine symptoms


1. Acephalgic pediatric migraine with visual disturbances and variable vision in school


2. Ophthalmic migraine in childhood


3. Ophthalmoplegic migraine


4. Classic migraine in the older student

C. Optic nerve disease with significant visual impairment


III. Systemic Diseases Associated with Vision and Neurologic Dysfunctions Potentially Affecting Learning

A. Metabolic and endocrinic diseases

B. Blood dyscrasias affecting the eye and brain

C. Metastatic neoplastic disease to the eye and/or brain


IV. The Ophthalmologist’s Role in Examining a Child and Advising the Family of a Defect in visual processing and/or learning is to rule out the presence of eye disease or related systemic disorder and to refer the pediatric patient to the proper professionals for more definitive diagnoses and subsequent treatment(s). In order to effectively do this, a classification of nonophthalmic learning disorders will now be outlined.

A. LDs (differences)


1. Developmental speech and language-based disorders (epidemiology)



a. Articulation disorders



b. Expressive language disorders



c. Receptive




i. Dyslexia—phonologic processing disorder





• genetics





• pathophysiology





• remediation





• early preschool identifying characteristics




ii. Other receptive language disorders


2. NLDs



a. Definition



b. Characteristics and affected areas of learning




i. visual-spatial perception




ii. visual memory




iii. psychomotor coordination




iv. complex tactile-perceptual skills




v. reasoning




vi. concept formulation




vii. mathematical abilities




viii. psychological behavioral difficulties




ix. strong verbal and reading skills



c. Early identification traits



d. Differential diagnosis



e. Methods of treatment. What exactly is optometric vision training?


3. ADHD (epidemiology)



a. Definition



b. Characteristics (DSM-IV) and diagnostic criteria observable during an eye exam




i. squirms in seat, fidgets with hand and/or feet




ii. unable to remain seated when required to do so




iii. easily distracted




iv. blurts out answers before a question is finished




v. difficulty following instructions




vi. unable to sustain attention in work activities




vii. interrupts or intrudes on others




viii. does not appear to listen




ix. loses items for tasks such as toys, pencils, and books




x. often engages in dangerous activities without considering the consequences



c. Subclassification




i. inattention




ii. impulsivity/hyperactivity



d. Common comorbid diagnosis E




i. Tourette syndrome/tic disorders




ii. conduct disorder




iii. oppositional defiant disorder




iv. other LDs




v. anxiety/depression


4. PDDs/ASDs



a. Definition



b. Characteristics—defects in social relatedness and language/communication skills



c. Subclassifications




i. Autism




ii. Asperger syndrome (chief eye symptom is “lack of eye contact”)




iii. Rett syndrome




iv. Pervasive developmental disorders, not otherwise specified



d. Referral and treatment options



e. Micro and primary dyskinetic strabismus as a presenting sign of PDD



f. Hyperlexia


Reprinted with permission from: Koller HP. An ophthalmologist’s approach to visual processing/learning differences. J Pediatr Ophthalmol Strabismus. 2002;39(3):140.


Although there are many migraine variants, Dorland’s6 goes on to define acute confusional migraine, which is a rare variant of classic migraine that occurs in children. It is marked by attacks of confusion and disorientation with agitation that manifest as a mixture of apprehension and combativeness. A headache may occur later. We have observed that the cause of frequent complaints of intermittent blurred vision in school-age children while in the classroom, with an otherwise normal eye examination, is migraine. Photophobia is the most common complaint of children who are found to have migraine. In adults, basal migraine is defined as that which results in a prodrome of visual field constriction with various other visual phenomena. In children, this may manifest in the classroom environment as intermittent blurred vision (fortification spectrum). However, on ophthalmologic examination, visual acuity of 20/20 in each eye, near and far, is frequently obtained, with normal stereopsis and no strabismus. They merely are experiencing the pediatric equivalent of adult, constricting visual fields, and the typical “scintillating scotoma.”7,8

Pediatric migraine, paramigraine phenomena, and/or associated symptoms in a school-aged child are very important to diagnose early to understand secondary ocular symptoms that might affect classroom efficiency. Migraine is a genetic disorder, and first-line blood relatives will likely have a history of vascular headache syndromes.9 In addition, the affected child will likely have a history of several of the following symptoms9:

Infantile colic

Lactose intolerance requiring a milk substitute

Frequent infantile febrile seizures

Unexplained abdominal discomfort on a recurrent basis

Photophobia

Phonophobia

Hyper smell sense

Allergic predisposition








TABLE 42-2. Visual Phenomena of Migraine









































































Silver streaks


White lights


Light objects appear excessively bright


All objects appear gray or yellow


Photophobia


Distortion of all linear objects


Dancing and moving cobwebs


Moving black veils


Scintillating picket fences


Silver stars


Wavy perpendicular lines


Flashing gold lights


Fourth-of-July sparklers (prevent reading)


Pinwheels


Welder’s sparks


Sparking star-like objects


Rotating gears


Visual field interference (multiple)


Diplopia


Zigzag streaks of light


Shimmering spots of light


Small pinpoint circles of light (red, yellow, blue)


Varicolored circles


Green spots (partial loss of vision)


Central bright-red flashing lights


Shimmering gray-brown spots (partial loss of vision)


Corrugated lines of light


Irregular reddish areas


Shimmering reddish circles (enlarge and interfere with vision)


Black spaces surrounded by shimmering triangles


Rotating black or dark gray spots


Halo vision (without glaucoma)


Herringbone pattern


Narrowed peripheral fields (prevents reading)


Reprinted with permission from Miller NR, Newman NJ. Migraine. In: Miller NR, Newman NJ, eds. Walsh and Hoyt’s Clinical Neuro-Ophthalmology. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1998:3664.


Sleep disturbances, including nightmares, night terrors, and sleep walking

Motion sickness, especially when riding in a motor vehicle

Type A personality

Macropsia/micropsia/metamorphopsia, in which things seem larger or closer than they actually are or smaller or farther away than they actually are, with and without associated distortion (the “Alice in Wonderland” syndrome)

Numerous other visual phenomena such as silver foils, sparkling lights, and seeing various colors at different times.

These last two symptoms are classified as ophthalmic or ocular migraine (Table 42.2).10


Diplopia without Strabismus

Migraine symptoms often go undetected in childhood and may be the only factor responsible for children with visual difficulties in school without other afflictions. Because these children frequently have type A personalities, the fact that they have recurrent disturbing symptoms without an apparent cause may in and itself cause them to have difficulty concentrating in school, the intermittent blurring notwithstanding. The blurring is believed to be a result of vascular constriction causing decreased blood supply to the retina. There are a significant number of children with defined learning disorders who also have migraine or paramigraine symptoms that may interfere with concentration and attention in the classroom and at home (personal observation).11

A comprehensive medical history and appropriate treatment are always indicated in severe cases that involve functional incapacity. The worst cases of migraine in children can involve ophthalmoplegias in which paralysis of one or more of the extraocular muscles causes diplopia. Double vision may last for hours or months and can be disturbing to the school-aged child. Diplopia without strabismus, however, is more frequent.9


LEARNING DISABILITIES

Learning disabilities (LDs) can be defined as “a generic term that refers to a heterogeneous group of disorders manifested by significant difficulties in the acquisition and use of listening, speaking, reading, writing, reasoning, or mathematic abilities. These disorders are presumed to be caused by CNS dysfunction and may occur in conjunction with other handicapping conditions (e.g., mental retardation, psychological problems) and environmental circumstances (e.g., poor instruction).”11 LD can take a variety of presentations on the basis of the symptoms that the child demonstrates (i.e., reading disorder, math disorder, disorder of impulse control, and disorder of social cognition) and can be a result of a variety of pathologic causes (i.e., genetic, environmental base).

The literature has reported that approximately 7% to 15% of all school-aged children have been diagnosed with an LD.12 Other samples have varied depending on definitions of LDs and sampling procedures.13,14 There has been much debate as to how to define and quantify LDs to enhance nosologic systems and diagnostic clarification. These diagnostic systems seem to differ between professional groups (i.e., physicians, psychologists, and educators) and jurisdictions (state by state). Several methods of defining LDs include (1) intellectual functioning versus achievement discrepancy, (2) response to intervention, and (3) cognitive processing models. All these methods of defining LDs have strengths and flaws and thus typically are used in combination.


Models of Learning Disabilities

The intellectual functioning versus achievement discrepancy model or aptitude versus achievement model is the most commonly used practice in diagnosing LDs in the school setting.15,16 The premise of this model is that the individual’s IQ score should be approximately equivalent with his or her academic achievement. Instances in which the achievement level is below the IQ score, by a certain degree (not defined in strict terms), would lead to the diagnosis of an LD. This model has advantages in that it is the easiest to operationally define and perform in a daily setting. The standards can be held in a rigid fashion by schools and are easy to enforce, and many of the most used testing tools used for diagnosis have been standardized together to allow for this process. However, there are many problems with this model, including the size of the discrepancy that is needed to diagnose LD and psychometric difficulties with testing (i.e., it is difficult to discover LD in younger children in this model because of the test properties and because LD may be more difficult to diagnose in children at the extremes of IQ). Moreover, this approach does not appreciate the aberrant cognitive processes that lead to the diagnosis, which would ultimately aid with the development of remediation strategies.

The response to intervention model proposes that children who fail to progress in school, with intensive instruction geared toward individual learning needs, are learning disabled.17 This model allows the classroom teacher to identify a struggling student for additional resource instruction prior to the diagnosis. The problem inherent with this model is the failure-based position of having to watch a child struggle until he or she can receive specialized instruction, possibly taking many years. This runs in contrast to most researchers including Shaywitz who reported that early intervention and specialized instruction have led to better functional outcomes.18 This methodology would hamper the child’s access to early interventions.

The cognitive processing model is one put forth by the field of neuropsychology.

Neuropsychology is a branch of psychology that studies the relationship between brain function and behavior.19 Neuropsychology, as a field, attempts to study areas of the brain and correlate certain behaviors (i.e., memory, language, attention/concentration, problem solving, reading, and math) with the underlying physiologic brain region. The neuropsychological study of LDs operates under the notion that brain systems develop in concert with the environment and stimulation to specialize in the processing of certain types of information. Foder20 called this modularity, and Pennington21 refers to this phenomenon as the genesis for the creation of his model for the study of LDs.

Foder’s20 modularity hypothesis also plays a role in the understanding of the development of LDs and the categorization of LD typologies that will be presented in this chapter. Cognitive functions exist in a systematic fashion (i.e., language, visual-perceptual) subsumed by regions in the brain that can be impacted during development through genetic, intrauterine, and/or environmental variables. Each type of LD has a certain prevalence in the community (reading disorders and attention deficit/hyperactivity disorder [ADHD] tend to be greater than nonverbal learning disorders [NLDs] and pervasive developmental disorders [PDDs]) because the brain systems that underlie reading (posterior left hemisphere) and attention (prefrontal cortex) tend to be more susceptible to damage than other brain regions that are involved in the other conditions.21 This model also allows for the study of comorbid disabilities (a frequent occurrence in the LD population) because the cause of the neuropathology may not always be circumscribed to one functional system. Ultimately, these systems would need to interact successfully to produce optimal academic and social performance.

The neuropsychological evaluation is a one-on-one evaluation performed by the clinician that typically lasts 6 to 8 hours (depending on the child’s age, levels of functioning, and referral question). The evaluation is designed to provide stimuli to elicit behaviors that will examine the functional systems of the brain. Neuropsychological evaluations typically study the following areas of functioning: (1) intellectual functioning, (2) attention/concentration, (3) learning and memory, (4) language, (5) visual-spatial/visual-motor skills, (6) executive functioning and problem solving, (7) motor/sensory skills, (8) academic skills (reading, writing, arithmetic), and (9) psychological/behavioral processing through a question-and-answer, paper-andpencil assessment (no imaging or invasive techniques are used). Traditional psychoeducational testing performed by the schools is subsumed within the neuropsychological evaluation.

The four basic types of LD based on functional brain systems will now be described. These types are (1) speech and language disorders, including most types of reading disorders, (2) NLDs, (3) ADHD, and (4) PDDs. It should be noted that other authors use different nomenclature and the reader should be aware of subtle differences in the literature.


SPEECH AND LANGUAGE DISORDERS

Articulation and expressive language disorders can be diagnosed grossly by taking a history from the parents and observing and hearing the child speak or not speak while seated in the ophthalmologist’s examining chair. If not already accomplished, these children should be referred to their primary care physician, ear, nose, and throat specialist, and speech and language pathologist. Typically, younger children are easier to recognize with pathologic conditions than older children, who may have more subtle problems with speech.

Auditory processing disorders are diagnosed and treated by ear, nose, and throat specialists, as well as speech and language pathologists.22,23 Treatment tends to focus on training auditory processing (sound discrimination, receptive vocabulary) and can also include classroom interventions (i.e., auditory systems for the classroom, teachers using different vocabulary).

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Jul 11, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on The Ophthalmologist’s Role in Visual Processing and Learning Disabilities

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