Diagnostic Evaluation of Children With Movement Disorders

Introduction

The approach to the diagnosis of a pediatric movement disorder often overlaps with other areas of pediatric medicine in requiring a careful medical, developmental, family, and social history and comprehensive physical examination. An additional requirement, however, is the need to observe, either in person or via video, and characterize the phenomenology of the disordered movement. While technological advances such as neuroimaging and rapid genome sequencing have modified our workflow, observation and classification remain indispensable. ^,

The time-tested approach to diagnosis of movement disorders involves pattern recognition of phenomenology and classification into one or more established categories ( Chapter 3 ). While this process typically precedes diagnostic neuroanatomic localization, clinical evaluation is accomplished more effectively when there is also a working understanding of the structure and function of the overlapping, integrated motor circuits involving the basal ganglia ( Chapter 1 ) and cerebellum ( Chapter 2 ). For more common and/or moderately specific symptoms, pattern recognition in the mind of an experienced clinician may narrow the differential diagnosis substantially. Ultimately, however, classification schemes commonly guide (1) decisions about whether to obtain additional medical diagnostic testing, and (2) approaches to treatment or management. The differential diagnosis, however, as in other areas of medicine, may remain extensive.

As discussed in Chapter 3 , the term movement disorder designates hyperkinetic and hypokinetic neurological phenomena that interfere with the initiation and precise execution of movement as well as abnormal involuntary movements. Some experts also include abnormalities in muscle tone (e.g., spasticity), coordination (e.g., ataxia), and complex disorders of execution of movement (e.g., apraxia). In general, conditions in which the primary problem is an interruption in the terminal pathway from the primary motor cortex to muscle (cortico-spinal and spinal cord-muscle) resulting in weakness are excluded. For example, there are numerous neurological disorders (e.g., motor cortex strokes, spinal cord diseases, anterior horn cell diseases, neuropathies, diseases at the neuromuscular junction, and myopathies) that interfere with movement but are not designated movement disorders. Rather, movement disorders typically result from an interruption in the adaptive function of subcortical and cerebellar structures and their circuits, the activity of which precedes signaling in motor cortex and in the final common pathway from motor neuron to muscle. In sum, cortico-basal ganglia-thalamo-cortical (CBGTC) circuits with inputs from the cerebellum and other regions (e.g., hippocampus and amygdala) subserve planning, selection, timing, and inhibition of movement. In parallel, they also subserve cognitive and emotional functions. As discussed in other parts of this book, the use of the terms “basal ganglia disorders” or “extrapyramidal disorders” used in the past to describe various movement disorders is now strongly discouraged.

In practice, movement disorders (CBGTC circuits) and abnormalities affecting movement (corticospinal, nerve, muscle) can overlap. For example, children with cerebral palsy may have mixed lesions with both spasticity and dystonia. Similarly, in the hereditary spastic paraplegias, affected individuals have varying symptoms and involvement of the cerebellum and basal ganglia. Thus, in this book, which aims to be comprehensive in its coverage of childhood diseases in which movement disorders may occur, there are extensive discussions of multiple pediatric neurological diseases.

It is also helpful throughout the diagnostic process of a child with a movement disorder to recognize the importance to the child and parent of having a normally functioning motor system and to assess the patient's perception of agency, or voluntariness. Full control over one's motor system for the automatic or voluntary execution of actions is often taken for granted by most persons during all waking hours. Development of movement control and a sense of agency for one's actions is a basic experience of childhood. Training in execution of skilled actions may occupy hundreds of hours in children and adolescents involved in the arts or sports. Loss of a sense of this control due to reduced efficiency of action performance, the occurrence of movements without a sense of agency, or compulsions to move repetitively without adaptive purpose often has psychological consequences. Any disease or disorder that interferes with the execution of movements can potentially cause substantial impairment, psychological distress (for the child or parent), and reduced quality of life. Hence, the treating physician should address personality traits and psychological distress as well as the disordered movement.

The most common movement disorders occurring in childhood (e.g., tics) will likely be seen by all general pediatric neurologists. These diagnoses are often reliably based on pattern recognition and, especially in milder cases, may require little clinician time, effort, or healthcare resources. In these individuals, a more time-consuming diagnostic challenge might be the identification of commonly cooccurring emotional or cognitive problems, tasks which often involve referrals to other specialists. In contrast, there are extremely rare movement disorders discussed in this book which may never be seen or diagnosed by most neurologists. Nevertheless, taken collectively, the presentation of a child with a rare movement disorder diagnosis is not a rare event in pediatric neurology. Indeed, many of the rare disorders are important to recognize as they are often treatable. ^, These diagnoses may be time-consuming for physicians, emotionally difficult for families, and costly for the healthcare system. Parents want their child's physician to make a specific diagnosis. Even if no medical treatment is available, a specific diagnosis, a cause for the problem, can bring emotional closure and support parental efforts.

A systematic but pragmatic approach to diagnosis of both rare and common movement disorders is the primary goal of this chapter. The approach is based on knowledge of relevant neuroanatomy ( Chapter 1, Chapter 2 ) and understanding of phenomenologic classification ( Chapter 3 ). Recognizing, however, that this chapter is not an encyclopedia of diagnoses, clinical features, imaging findings, or genes, the goal of this chapter is to address general approaches to obtaining the most comprehensive and accurate information in the clinic and the subsequent application of this information to making both straightforward and difficult diagnoses. Utilizing this approach, a provisional diagnosis, or at least a narrowed differential diagnosis, should be achievable for most children referred for movement disorders.

The skill of recognition of movement disorder phenomenology involves practiced visual pattern recognition, an understanding of the neuroanatomy of motor control, and foundation in movement disorder classification systems. A fundamental challenge in evaluating children is that the nervous system is developing, and the term “normal” or “typical” is a moving target. Further, diseases can manifest in different forms at varying stages of motor system maturation. Lastly, children may not communicate symptoms and will not always cooperate with the examination. Diagnosis through pattern recognition is greatly enhanced by clinical experience and training in the medical care of healthy and neurologically impaired children as well as by independent reading and the study of case videos.

This chapter is organized in the framework of a new clinic visit for a chief complaint of a movement disorder, with the primary goal being a stepwise phenomenological diagnosis. The elements of a typical outpatient visit form the chapter sections. The use of computer databases for diagnosis is discussed in the final section.

Preclinic

The Scheduling Process

Some institutions support clinics devoted specifically to pediatric movement disorders. This requires an appropriate triaging process where schedulers have a list of chief complaints. Essentially, the appropriate referrals include conditions listed as chapter titles in this book. For children, this works well for common problems such as tremor or tics that are readily recognized by referring physicians (or self-referring parents). Other problems, such as ataxia, dystonia, or chorea, create greater difficulties because referring physicians and office staff may not know how to describe the problem or whether it is a movement disorder. However, once a clinic program becomes established in a community, with good physician communication and marketing, the percentage of appropriate referrals is likely to improve.

Urgent Referrals

Most movement disorders are chronic and not life-threatening. Therefore, emergency department consultations and medically urgent scheduling encompass a small fraction of neurologist encounters for movement disorders. However, some movement disorders, including those listed in Table 4.1 , may emerge and become disabling fairly rapidly. Costly emergency department visits sometimes can be avoided with flexible scheduling and supportive clinician communication about urgent visits. Recognizing both real disability in children and overwhelming distress in some parents, it is important to have mechanisms in place to facilitate rapid evaluation of patients. The successful pediatric neurologist should be available for some form of direct communication from primary care physicians and advanced practice providers who may need to advocate for children with particularly impairing movement disorders. Parents often advocate directly for their children through phone calls or electronic communication. An advantage of email and other electronic communications is that parents can provide chief complaint and history of present illness data and even videos in advance, which can assist with the triaging process.

Table 4.1

Acute, Subacute Pediatric Movement Disorders Which May Present Urgently

Movement disorder phenomenology	Most common etiology or precipitant	Comment
Acute ataxia	Postinfectious/postvaccine	Usually causes significant functional interference
Akathisia, ataxia, chorea, dyskinesias, dystonia, myoclonus, rigidity with hyperthermia, tics, tremor while starting, adjusting, stopping psychiatric medications	Drug-induced, particularly related to dopamine receptor blockers	Acute akathisia or dystonic reactions, withdrawal emergent dyskinesias on rapid neuroleptic withdrawal
Chorea	Poststreptococcal (Sydenham), other immune mediated	Usually causes significant functional interference
Chorea/ballism	Fever/illness in children with dyskinetic cerebral palsy	Can lead to rhabdomyolysis
Dystonia/status dystonicus	Variable—for example, neurodegenerative diseases, baclofen pump failure	Can lead to rhabdomyolysis, respiratory compromise
Encephalopathy with any facial dyskinesia or mixed movement disorder	Encephalitis	Anti-NMDA receptor, other auto-immune
Functional movement disorders: Psychogenic tremor/shaking, tics, gait disturbance, dystonia	Acute stressors often not identified in children	Early diagnosis is probably critical for improving prognosis
Opsoclonus myoclonus	Unknown	Usually causes significant functional interference
Tics/status ticcus	Sometimes acute stressor	Tourette Syndrome or provisional tic disorder may present or exacerbate dramatically in the absence of an identifiable precipitant

Gathering Data Before the Visit

Standardized intake questionnaires can yield essential information for the diagnostic evaluation. Much of this information can be effectively provided by parents before the visit; however, for many families, attempts to obtain extensive information before the visit will have low yield. Sending questionnaires by regular mail is expensive and time-intensive for staff, and emailing long intake questionnaires before the visit can also have low yield, particularly for new patients or families without good computers or access to a printer. An additional inconvenience is questionnaires that require scanning or data entry after the visit. Probably the most effective options at present are questionnaires of modest length sent out through the scheduling process formatted to be filled out on a smart phone with an automatic upload into the patient record. Video files or links may also be sent prior to the visit. Indeed, good quality of home videos taken before or after the clinic encounter can markedly enhance the diagnostic process, particularly in patients with paroxysmal or fluctuating movement disorders.

In Clinic

The goal of the first clinic encounter is to arrive at a specific diagnosis or to formulate a plan that will lead to a diagnosis and eventually to a specific treatment. It is helpful to bear in mind that the most common movement disorder complaints in children, tics and stereotypies, while usually benign, may be emotionally distressing to parents. Through history, examination, and direct observation, the clinician should obtain an accurate impression of the movement phenomenology. Another important goal is to establish a trusting relationship with the child and family to facilitate appropriate, beneficial long-term management.

In the Waiting Room/Check-in by Ancillary Personnel or Nursing

Some information about phenomenology can be gathered before entry into the clinic room. One obvious example is loud vocal tics. However, more severe problems affecting gait or involuntary movements can be observed in the waiting room or during check-in when vital signs are being obtained. Staff can also gauge parental anxiety and may record the primary movement disorder of concern to the family. The use of tablets during the check in process and in the waiting room to obtain background information, details about the chief complaint, impairment related to the movement disorder, and impairment related to commonly cooccurring problems like ADHD symptoms, in a form that is automatically uploaded into the electronic patient record, is extremely helpful.

The First Physician Encounter in the Clinic Room

Some parents may wish to discuss the chief complaint with the physician separately, without the child present. This is often counterproductive, as it may reinforce or create anxiety in the child about the problem. Verbal, school age children usually know they have the movement for which they are being evaluated.

The first minutes of the clinic room encounter with the physician are very important for both the diagnosis and the therapeutic alliance. After a brief introduction to parents, the clinician should focus on the child. This provides an important opportunity for observation, during which the chief complaint may often be directly observed. For an infant, this can involve complimenting the child's appearance and asking to hold him or her. For toddlers or older children who may be playing in the room, watching or participating in their play with toys can be useful. When children are engaged with cell phones or other electronic devices, quick observation of their interactions with the device, followed by handing the device to the parent is advisable, as is turning off any other distracting electronics in the room.

Interviewing the Child

The diagnostic assessment is best served by opening the conversation with topics such as fun after-school activities, hobbies, sports, music participation, pets, and/or best friends. An age-appropriate conversation about these topics helps make the child feel comfortable, so that the history and examination are more likely to be informative. This also provides essential information for assessing symptom-related impairment and making treatment decisions later. Finally, parents usually appreciate kind and direct interaction by the physician with the child.

During this conversation, continuous abnormal movements will be observed if present. Also, intermittent or paroxysmal movements may be observed. Many children are anxious in clinic and may be embarrassed about their movement disorder. Sensing this, a clinician may set the child more at ease by indicating that he has observed the movements during the conversation and that they resemble movements in some other boys and girls. The reassured, less anxious child may then be able to provide additional important information and cooperation during the examination.

Data about the movement disorder to be obtained from the child include the following:

Awareness of the movement in real time
Preceding/premonitory sensations, urges, or intrusive thoughts related to the movement
Volition—is there agency (a perception of voluntariness)? Is the movement perceived as involuntary?
Suppressibility, even briefly, and whether an urge or tension builds up during suppression
Whether, after suppression, a rebound increase in movements occurs
Exacerbating and ameliorating factors
Associated pain
Effect of purposeful actions, for example, during the fun activities already discussed, using the same body area as that involved in the movement disorder
Functional interference/effect on performance
Awareness, comments on the movement by previously discussed friends or teachers
Associated social embarrassment/effect on peer relationships and activity participation
Any effect on school performance or education

Interviewing the Parents/Guardians

While it is important to attempt to obtain most of this information, in an age-appropriate way, from the child, often the child's account will have gaps. During the remainder of the history, the parents/guardians can provide complementary and usually more detailed and accurate information. This may be efficiently provided as well on a standardized intake questionnaire. A preclinic review of the electronic health record also helps with effective, comprehensive evaluations. In clinic, parents/guardians can provide the following information:

Verification of the details above, provided by the child
Past diagnostic testing for this movement disorder, if any
Past treatments for this movement disorder, if any
Current and past medications
Past medical history: Detailed prenatal and perinatal history including maternal health, diseases, medication or substance use, delivery, postnatal hospitalization, jaundice
Other medical diagnoses
Neurologic development: skill acquisition—gross motor, fine motor, speech, and language
Academic performance: for example, whether the child reads at grade level
Provision of school-based services like speech, occupational, or physical therapy
Emotional/behavioral and cognitive problems
Past school testing details
Review of systems
Family history—movement disorders, neurologic, psychiatric, or learning disorders and diseases. At least three generations (siblings; parents, aunts, uncles; grandparents)
Parent education and occupation
Social history/recent stressors/substance abuse history

The family history may be critical to identifying the etiology. Neurologists must understand patterns of inheritance: autosomal dominant and recessive, X-linked, and maternal/mitochondrial. Other important concepts are penetrance, genetic anticipation, premutation status, copy number variation, toxic gain of function, and haplotype insufficiency (See Table 4.2 ). The examiner should be sensitive to the possibility that parents may feel guilty or sad about the role of genetics in their child's symptoms. Inquiring about consanguinity can be important and may require an understanding approach. Ethnic backgrounds may also narrow the differential diagnosis.

Table 4.2

Definitions of Genetic Terms Related to Variability in Disease Expression

Term	Definition	Example
Penetrance	The frequency of expression of an allele when it is present in the genotype; the frequency with which a heritable trait occurs in individuals carrying the principal gene(s) for that trait	The penetrance of DYT1 mutations is 30%; 30% of persons carrying the GAG deletion in the DYT1 gene develop dystonia
Genetic anticipation	When genetically transmitted diseases manifest earlier or more severely in successive generations	The biological basis for genetic anticipation in Huntington disease is expansion of trinucleotide CAG repeats in the huntingtin (HTT) gene, leading to increasingly dysfunctional protein/earlier onset
Premutation status	A genetic variation that increases the risk of disease in subsequent generations	Based on the number of CGG repeats in the FMR-1 (Fragile X) gene, the status of individuals may be classified as healthy, premutation, or full mutation
		Normal : Fewer than 54 CGG repeats
		Premutation : Male or female carrier with 54–200 CGG repeats; premutation females are unaffected or mildly affected cognitively but are at risk for affected sons with full mutation. Premutation males over age 50 are at risk for Fragile X tremor ataxia syndrome
		Full mutation : Trinucleotide CGG expansion over 200 causing Fragile X syndrome with autism, intellectual disability
Haplo-insufficiency/haplotype insufficiency	When a mutation occurs in one gene, and the amount of protein produced by the other gene is insufficient for healthy function. This concept that disease symptoms may depend on gene dosage/protein dosage may partially explain differences in penetrance and disease severity in autosomal dominant, single gene diseases	Haplo-insufficiency has been suggested to play a role in forms of disease expression related to potassium channel subunits and to mitochondria-regulating polymerase gamma1 (POLG1)
Copy number variation (CNV)	In comparative genome studies, segments of DNA have been identified where duplications, deletions, inversions, or translocations have resulted in changes in copy number. These CNVs are heritable and may affect gene expression	CNV has been suggested to play a role in susceptibility to autism, schizophrenia, Tourette Syndrome, and Parkinson disease

The previously described history-taking process is usually sufficient to diagnose tic disorders and stereotypies in otherwise healthy children. For these common, patterned, hyperkinetic movement disorders, the amount of additional information gained from the general and neurologic examinations may be small. However, the examination is important for distinguishing tics from functional movement disorders ^, and may provide useful, nonspecific complementary information, for example, about fine motor coordination. In addition, the examination remains important for those less prevalent instances of a secondary tic disorder. Another important purpose of the examination is to reassure anxious parents. It is easier (and more appropriate) to convey reassurance about the child's neurologic health and development if there has been a moderately thorough neurologic examination, even in cases where the examination adds no new information. In academic clinic settings where a trainee has been the initial examiner, it is important for the attending physician to “lay on the hands” as well. When staffing the encounter with the trainee, the attending physician should establish a friendly rapport with the parents and child and repeat key portions of the motor examination, even if she or he trusts this has been competently performed by the trainee.

The Physical and Neurologic Examination

The examination begins with observation and ideally may include observation in the waiting room, during walking into the clinic room, and in all cases during the previously described interview.

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