Oculomasticatory myorhythmia: a unique movement disorder occurring in Whipple's disease

A Case of Anti-Ma2 Encephalitis Presenting with Pendular Torsional Nystagmus

Antibodies against the neuronal protein Ma2 have been reported in a peculiar form of paraneoplastic encephalitis with prominent involvement of the limbic, brainstem, and diencephalic structures and usually associated with germ cell testicular, lung, or breast cancer. The diagnosis is frequently challenged by atypical clinical manifestations including parkinsonism, sleep disturbances, hypothalamic-pituitary dysfunctions, and motor neuron-like syndrome. In recent years, the advent of monoclonal antibodies targeting immune checkpoints has deeply changed the treatment of different tumors, especially melanoma and lung cancer. However, given their nature, an increasing number of neurological immune-related adverse events, including ocular motor abnormalities, have been described. Here, we report a woman with advanced non-small cell lung cancer treated with anti-PD-L1 durvalumab, presenting with an isolated pendular torsional nystagmus, in association with anti-Ma2 antibodies. This peculiar case widens our knowledge on the clinical presentation of anti-Ma2 encephalitis associated with checkpoint inhibitors.

How to face the hemifacial spasm: challenges and misconceptions

Hemifacial spasm (HFS) is characterised by intermittent, brief or sustained, repetitive contractions of the muscles innervated by one facial nerve. It is one of the most frequent movement disorders affecting the face. However common and allegedly straightforward to diagnose, it might reveal as a challenge for clinicians in various situations. Indeed, it often needs prior exclusion of many other movement disorders affecting the face, with frequent phenomenological overlaps with blepharospasm, post-facial palsy, facial motor tics, etc. The clinical diagnosis shall be supported by modern brain imaging techniques, and sometimes electromyography, as some particular aetiologies may require specific treatment. Primary forms are associated with vascular compression of the ipsilateral seventh cranial nerve, whereas secondary forms can be caused by any injury occurring on the facial nerve course. This article proposes a global and organised approach to the diagnosis, and the ensuing therapeutic options, as many practitioners still use some inefficient medications when they encounter a case of facial spasm.

Ophthalmic manifestations of Whipple's disease

PURPOSE OF REVIEW

Whipple's disease is an infectious cause of uveitis that may present with nonspecific findings of intraocular inflammation, which can precede the development of neurologic symptoms and signs. Whipple's disease, then, may evade consideration in the differential diagnosis for uveitis.

RECENT FINDINGS

Molecular tests can be helpful in identifying the presence of Tropheryma whipplei from ocular specimens. The application of metagenomic sequencing for ocular specimens is promising, as it offers the opportunity to identify the pathogen when suspicion for an intraocular infection is high. Whipple's disease demonstrates the ability to abrogate the host immune response, which gives some insight into its pathogenesis.

SUMMARY

Whipple's disease should be suspected in patients who have uveitis refractory to anti-inflammatory therapy. Knowledge of this important pathogen can help direct the timely implementation of diagnostic testing.

Ocular Whipple Disease: Cases Diagnosed Over Four Decades

PURPOSE

To describe ocular involvement in subjects with Whipple's disease (WD).

METHODS

Retrospective review of documented WD cases seen at Mayo Clinic between 1980 and 2021 with ocular involvement.

RESULTS

Of 217 patients with WD, 30 had eye exams and four (two female, median age 58.5 years) had ocular involvement. Findings included anterior/intermediate uveitis (n = 2), intermediate uveitis and phlebitis (n = 1), and chorioretinitis with vitritis (n = 1). The diagnosis was confirmed by vitreous biopsy in three of four cases. In two cases, WD diagnosis was unconfirmed prior to the ocular diagnosis. Systemic manifestations included gastrointestinal symptoms in all patients, synovitis (n = 3), weight loss (n = 2), and pericarditis (n = 1). Mean time from onset of ocular symptoms to ocular diagnosis was 11 months (range 2-28 months). Prior systemic symptoms were present as long as 3 years.

CONCLUSIONS

WD is uncommon and ocular involvement is even more rare. However, WD should be considered in the differential for all patients with chronic recalcitrant uveitis, especially in the setting of polyarthralgias and/or gastrointestinal symptoms. Vitreous biopsy is a reliable method to diagnose ocular WD.Abbreviations and Acronyms: Whipple's disease (WD), intestinal lipodystrophy (IL), polymerase-chain reaction (PCR), periodic acid-Schiff (PAS), trimethoprim/sulfamethoxazole (TMP/SMX).

Diagnostic Uncertainties in Tremor

The approach and diagnosis of patients with tremor may be challenging for clinicians. According to the most recent consensus statement by the Task Force on Tremor of the International Parkinson Movement Disorder Society, the differentiation between action (i.e., kinetic, postural, intention), resting, and other task- and position-specific tremors is crucial to this goal. In addition, patients with tremor must be carefully examined for other relevant features, including the topography of the tremor, since it can involve different body areas and possibly associate with neurological signs of uncertain significance. Following the characterization of major clinical features, it may be useful to define, whenever possible, a particular tremor syndrome and to narrow down the spectrum of possible etiologies. First, it is important to distinguish between physiological and pathological tremor, and, in the latter case, to differentiate between the underlying pathological conditions. A correct approach to tremor is particularly relevant for appropriate referral, counseling, prognosis definition, and therapeutic management of patients. The purpose of this review is to outline the possible diagnostic uncertainties that may be encountered in clinical practice in the approach to patients with tremor. In addition to an emphasis on a clinical approach, this review discusses the important ancillary role of neurophysiology and innovative technologies, neuroimaging, and genetics in the diagnostic process.

Limb myorhythmia treated with chemodenervation: a case report

We describe a case of limb myorhythmia successfully palliated with botulinum toxin injections. The patient is a 30-year-old male evaluated for abnormal movements of the left lower foot that began after an ankle injury for which the patient underwent Achilles tendon scar tissue debridement without improvement. On examination, he had near-constant involuntary, slow, rhythmic flexion/extension tremor of toes 2-4 that was diminished during active movement. Needle electromyography (EMG) revealed a rhythmic, 2-3 Hz tremor isolated to the flexor digitorum brevis. After failure of medical management with muscle relaxants, gabapentin, and levodopa trials, the patient underwent two EMG-guided chemodenervation procedures with incobotulinum toxin A injections of the left flexor digitorum brevis. At 3-month follow-up, he had achieved a sustained 50% reduction in the intensity of the movements and improved quality of life. Myorhythmia is a rare condition characterized by a repetitive, rhythmic, slow frequency (1-4 Hz) movement affecting the cranial and limb muscles. The most common causes include stroke, demyelinating disorders, drug or toxin intake, trauma, and infections. The management of this condition is very limited with pharmacologic agents such as anticholinergics, antispasmodics, anticonvulsants, or dopaminergic agents showing limited efficacy. The use of botulinum toxin chemodenervation aided by EMG muscle targeting can be a useful therapeutic intervention in cases of medication-refractory regionally distributed myorhythmia involving accessible muscles.

Eye Movement Disorders in Movement Disorders

Oculomotor assessment is an essential element of the neurological clinical examination and is particularly important when evaluating patients with movements disorders. Most of the brain is involved in oculomotor control, and thus many neurological conditions present with oculomotor abnormalities. Each of the different classes of eye movements and their features can provide important information that can facilitate differential diagnosis. This educational review presents a clinical approach to eye movement abnormalities that are commonly seen in parkinsonism, ataxia, dystonia, myoclonus, tremor, and chorea. In parkinsonism, subtle signs such as prominent square wave jerks, impaired vertical optokinetic nystagmus, and/or the "round the houses" sign suggest early progressive supranuclear gaze palsy before vertical gaze is restricted. In ataxia, nystagmus is common, but other findings such as oculomotor apraxia, supranuclear gaze palsy, impaired fixation, or saccadic pursuit can contribute to diagnoses such as ataxia with oculomotor apraxia, Niemann-Pick type C, or ataxia telangiectasia. Opsoclonus myoclonus and oculopalatal myoclonus present with characteristic phenomenology and are usually easy to identify. The oculomotor exam is usually unremarkable in isolated dystonia, but oculogyric crisis is a medical emergency and should be recognized and treated in a timely manner. Gaze impersistence in a patient with chorea suggests Huntington's disease, but in a patient with dystonia or tremor, Wilson's disease is more likely. Finally, functional eye movements can reinforce the clinical impression of a functional movement disorder.

Rapidly progressive dementia and intractable diarrhea: a teaching case report and a systematic review of cognitive impairment in Whipple’s disease

Objective

Methods

Results

Conclusions

Supplementary Information

Classification of vestibular signs and examination techniques: Nystagmus and nystagmus-like movements

This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations.

View accompanying videos at http://www.jvr-web.org/ICVD.html

Fatal familial insomnia and Agrypnia Excitata: Autonomic dysfunctions and pathophysiological implications

Fatal Familial Insomnia (FFI) is a hereditary prion disease caused by a mutation at codon 178 of the prion-protein gene leading to a D178N substitution in the protein determining severe and selective atrophy of mediodorsal and anteroventral thalamic nuclei. FFI is characterized by physiological sleep loss, which polygraphically appears to be a slow wave sleep loss, autonomic and motor hyperactivation with peculiar episodes of oneiric stupor. Alteration of autonomic functions is a great burden for FFI patients consisting in sympathetic overactivation, dysregulation of its physiological responses and disruption of circadian rhythms. The cardiovascular system is the most frequently and severely affected confirming the increased sympathetic drive with preserved parasympathetic responses. Sleep loss, autonomic and motor hyperactivation define Agrypnia Excitata (AE), which is not exclusive to FFI, but it has been canonically described also in Morvan Syndrome and Delirium Tremens. These three conditions present different pathophysiological mechanisms but share the same thalamo-limbic impairment of which AE is one of the possible clinical presentations. FFI, and consequently also AE, is a model for the investigation of the essential role of the thalamus in the organization of body homeostasis, integrating both sleep and autonomic function control.

Approach to the Examination and Classification of Nystagmus

BACKGROUND AND PURPOSE

Physical therapists caring for patients with neurologic or vestibular disorders must routinely examine and characterize nystagmus and other oscillatory eye movements. Often, the diagnosis hinges on proper interpretation of the nystagmus pattern. This requires understanding the terminology surrounding the numerous attributes and influencing factors of nystagmus, a systematic approach to the examination, and a classification structure that guides practitioners to the specific nystagmus type and subsequent evaluation and management.

SUMMARY OF KEY POINTS

Nystagmus is an involuntary, rapid, rhythmic, oscillatory eye movement with at least 1 slow phase. Jerk nystagmus has a slow phase and a fast phase. Pendular nystagmus has only slow phases. Nystagmus is distinguished from other types of oscillatory eye movements, such as saccadic intrusions or oscillations. Characterizing nystagmus requires clearly describing its trajectory. This includes choosing a reference frame to describe the axes or planes and direction of eye movements. Several attributes are used to describe nystagmus: binocularity, conjugacy, velocity, waveform, frequency, amplitude, intensity, temporal profile, and age at first appearance. Several factors may influence nystagmus, including gaze position, visual fixation, vergence, and a variety of provocative maneuvers. Classification of nystagmus may be organized by physiologic or pathologic nystagmus versus other nystagmus-like movements. Pathologic nystagmus may be spontaneous, gaze-evoked, or triggered by provocative maneuvers. The combination of attributes allows differentiation between the many peripheral and central forms.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Therapists should carefully examine and characterize the trajectory and other attributes and influencing factors of nystagmus to accurately classify it and arrive at the correct diagnosis.

Abnormal Eye Movements in Parkinsonism and Movement Disorders

Abnormal eye movements are commonly observed in movement disorders. Ocular motility examination should include bedside evaluation and laboratory recording of ocular misalignment, involuntary eye movements, including nystagmus and saccadic intrusions/oscillations, triggered nystagmus, saccades, smooth pursuit (SP), and the vestibulo-ocular reflex. Patients with Parkinson’s disease (PD) mostly show hypometric saccades, especially for the self-paced saccades, and impaired SP. Early vertical saccadic palsy is characteristic of progressive supranuclear palsy-Richardson’s syndrome. Patients with cortico-basal syndrome typically show a delayed onset of saccades. Downbeat and gaze-evoked nystagmus and hypermetric saccades are characteristic ocular motor findings in ataxic disorders due to cerebellar dysfunction. In this review, we discuss various ocular motor findings in movement disorders, including PD and related disorders, ataxic syndromes, and hyperkinetic movement disorders. Systemic evaluation of the ocular motor functions may provide valuable information for early detection and monitoring of movement disorders, despite an overlap in the abnormal eye movements among different movement disorders.

Tremor

Tremor is a phenomenon observed in a broad spectrum of diseases with different pathophysiologies. While patients with tremor may not complain in the clinic of symptoms of imbalance, gait difficulties, or falls, laboratory research studies using quantitative analysis of gait and posture and neurophysiologic techniques have demonstrated impaired gait and balance across a variety of tremor etiologies. These findings have been supported by careful epidemiologic studies assessing symptoms of imbalance. Imaging and neurophysiologic studies have identified cerebellar networks as important mediators of tremor, and therefore a likely common site of dysfunction to explain the phenomenologic overlap between impaired postural and gait control with tremor. Further understanding of these mechanisms and networks is of crucial importance in the development of new treatments, particularly surgical or minimally invasive lesional therapies.

The diagnostic value of saccades in movement disorder patients: a practical guide and review

Saccades are rapid eye movements designed to shift the fovea to objects of visual interest. Abnormalities of saccades offer important clues in the diagnosis of a number of movement disorders. In this review, we explore the anatomy of horizontal and vertical saccades, discuss practical aspects of their examination, and review how saccadic abnormalities in hyperkinetic and hypokinetic movement disorders aid in diagnosis, with video demonstration of classic examples. Documentation of the ease of saccade initiation, range of motion and conjugacy of saccades, speed and accuracy of saccades, dynamic saccadic trajectory, and the presence or absence of saccadic intrusions and oscillations are important components of this exam. We also provide a practical algorithm to demonstrate the value of saccades in the differential diagnosis of the movement disorders patient.

The Dystonias

Dystonia is a difficult problem for both the clinician and the scientist. It is sufficiently common to be seen by almost all physicians, yet uncommon enough to prevent any physician from gaining broad experience in its diagnosis and treatment. Each case represents a difficult challenge even to the specialist. The basic scientist is faced with investigating a disorder that is without relevant animal models and which is so rare that obtaining suitable tissue for study is a major obstacle. Dystonia may be idiopathic, or associated with lesions from many sources, including a variety of rare diseases. If idiopathic, it may be genetically transmitted or sporadic. If genetically transmitted, it may be generalized or focal, with symptoms varying in different members of the same family. It may be refractory to treatment, or it may respond to any one of a number of individual drugs that have very different mechanisms of action. For idiopathic dystonias, no clear method of genetic transmission has been established and no consistent pathology identified.

Movement disorders in systemic diseases

Movement disorders, classically involving dysfunction of the basal ganglia commonly occur in neurodegenerative and structural brain disorders. At times, however, movement disorders can be the initial manifestation of a systemic disease. In this article we discuss the most common movement disorders which may present in infectious, autoimmune, paraneoplastic, metabolic and endocrine diseases. Management often has to be multidisciplinary involving primary care physicians, neurologists, allied health professionals including nurses, occupational therapists and less frequently neurosurgeons. Recognizing and treating the underlying systemic disease is important in order to improve the neurological symptoms.

Central ocular motor disorders, including gaze palsy and nystagmus

An impairment of eye movements, or nystagmus, is seen in many diseases of the central nervous system, in particular those affecting the brainstem and cerebellum, as well as in those of the vestibular system. The key to diagnosis is a systematic clinical examination of the different types of eye movements, including: eye position, range of eye movements, smooth pursuit, saccades, gaze-holding function and optokinetic nystagmus, as well as testing for the different types of nystagmus (e.g., central fixation nystagmus or peripheral vestibular nystagmus). Depending on the time course of the signs and symptoms, eye movements often indicate a specific underlying cause (e.g., stroke or neurodegenerative or metabolic disorders). A detailed knowledge of the anatomy and physiology of eye movements enables the physician to localize the disturbance to a specific area in the brainstem (midbrain, pons or medulla) or cerebellum (in particular the flocculus). For example, isolated dysfunction of vertical eye movements is due to a midbrain lesion affecting the rostral interstitial nucleus of the medial longitudinal fascicle, with impaired vertical saccades only, the interstitial nucleus of Cajal or the posterior commissure; common causes with an acute onset are an infarction or bleeding in the upper midbrain or in patients with chronic progressive supranuclear palsy (PSP) and Niemann-Pick type C (NP-C). Isolated dysfunction of horizontal saccades is due to a pontine lesion affecting the paramedian pontine reticular formation due, for instance, to brainstem bleeding, glioma or Gaucher disease type 3; an impairment of horizontal and vertical saccades is found in later stages of PSP, NP-C and Gaucher disease type 3. Gaze-evoked nystagmus (GEN) in all directions indicates a cerebellar dysfunction and can have multiple causes such as drugs, in particular antiepileptics, chronic alcohol abuse, neurodegenerative cerebellar disorders or cerebellar ataxias; purely vertical GEN is due to a midbrain lesion, while purely horizontal GEN is due to a pontomedullary lesion. The pathognomonic clinical sign of internuclear ophthalmoplegia is an impaired adduction while testing horizontal saccades on the side of the lesion in the ipsilateral medial longitudinal fascicule. The most common pathological types of central nystagmus are downbeat nystagmus (DBN) and upbeat nystagmus (UBN). DBN is generally due to cerebellar dysfunction affecting the flocculus bilaterally (e.g., due to a neurodegenerative disease). Treatment options exist for a few disorders: miglustat for NP-C and aminopyridines for DBN and UBN. It is therefore particularly important to identify treatable cases with these conditions.

Whipple's in the valleys: a case of Whipple's with thrombocytopenia and endocarditis

INTRODUCTION

This case report details the second described case of Whipple's disease-related thrombocytopenia in the medical literature. Whipple's disease is a rare multisystem infection caused by the actinomycete Tropheryma whipplei, first described by George Whipple in 1907. The key clinical manifestations are weight loss, diarrhoea and malabsorption, but arthralgia and endocarditis are also well described.

CASE PRESENTATION

A 62-year-old Caucasian female presented with weight loss, anaemia and behavioural changes but denied any abdominal symptoms. Thrombocytopenia subsequently developed rapidly. Bone marrow examination showed abundant megakaryocytes in keeping with peripheral platelet sequestration. In addition, there was significant polyclonal plasmacytosis. She was also found to have a 1.6 cm tricuspid vegetation. The diagnosis was confirmed by presence of foamy macrophages on duodenal biopsy, positive periodic acid-Schiff staining and visualisation of T whipplei actinomycetes on electron microscopy. Tissue PCR performed mid-treatment showed traces of T whipplei DNA. The infection was treated with a 2-week intravenous course of ceftriaxone followed by 12 months of oral co-trimoxazole. The thrombocytopenia and anaemia resolved rapidly with antibiotic therapy, her behaviour returned to normal and she remains clinically well.

CONCLUSIONS

This report confirms the association of thrombocytopenia with Whipple's disease, likely due to peripheral platelet sequestration, which resolves rapidly with treatment. In patients with a long history of unintended weight loss, Whipple's disease is a rare but important differential diagnosis as it is ultimately fatal if left untreated.

Isolated CNS Whipple disease with normal brain MRI and false-positive CSF 14-3-3 protein: a case report and review of the literature

Whipple disease (WD) is usually a systemic infectious disease that can have central nervous system (CNS) involvement. WD confined to the CNS is extremely rare and difficult to diagnose, but can be fatal if not treated in a timely fashion. We present the case of a 42-year-old man with a subacute dementia accompanied by a movement disorder consisting of progressive supranuclear gaze palsy, myoclonus, and ataxia. Our patient lacked the typical magnetic resonance imaging (MRI) findings reported with isolated CNS WD and had a false-positive cerebrospinal fluid (CSF) 14-3-3 protein. The patient expired, and definitive diagnosis of isolated CNS WD was made by autopsy with characteristic macrophage accumulations found in the brain but not in the gastrointestinal tract. We examine the literature on isolated CNS WD and discuss how these previously unreported findings make a rare diagnosis even more challenging. The reported patient is the first in the literature with tissue diagnosis of isolated CNS WD in the setting of normal brain MRI and positive CSF 14-3-3 protein. Isolated CNS WD should be added to the list of considerations for a false-positive CSF 14-3-3 protein. Even in the absence of typical MRI lesions, a patient with subacute progressive dementia, supranuclear gaze palsy, and other various neurologic abnormalities should have the diagnosis of isolated CNS WD considered.

Rapidly progressive Whipple's disease of the central nervous system

We describe a patient with rapidly progressive Whipple's disease confined to the central nervous system (CNS). The diagnosis was made pre-mortem following stereotactic and open brain biopsis and confirmed at autopsy. Despite appropriate antibiotic treatment, the disease ran a fulminant course to death after nine weeks.

The emerging link between autoimmune disorders and neuropsychiatric disease

Abnormal autoimmune activity has been implicated in a number of neuropsychiatric disorders. In this review, the authors discuss a newly recognized class of synaptic autoimmune encephalitides as well as behavioral and cognitive manifestations of systemic autoimmune diseases.

Progressive dementia associated with ataxia or obesity in patients with Tropheryma whipplei encephalitis

Background

Tropheryma whipplei, the agent of Whipple's disease, causes localised infections in the absence of histological digestive involvement. Our objective is to describe T. whipplei encephalitis.

Methods

We first diagnosed a patient presenting dementia and obesity whose brain biopsy and cerebrospinal fluid specimens contained T. whipplei DNA and who responded dramatically to antibiotic treatment. We subsequently tested cerebrospinal fluid specimens and brain biopsies sent to our laboratory using T. whipplei PCR assays. PAS-staining and T. whipplei immunohistochemistry were also performed on brain biopsies. Analysis was conducted for 824 cerebrospinal fluid specimens and 16 brain biopsies.

Results

We diagnosed seven patients with T. whipplei encephalitis who demonstrated no digestive involvement. Detailed clinical histories were available for 5 of them. Regular PCR that targeted a monocopy sequence, PAS-staining and immunohistochemistry were negative; however, several highly sensitive and specific PCR assays targeting a repeated sequence were positive. Cognitive impairments and ataxia were the most common neurologic manifestations. Weight gain was paradoxically observed for 2 patients. The patients' responses to the antibiotic treatment were dramatic and included weight loss in the obese patients.

Conclusions

We describe a new clinical condition in patients with dementia and obesity or ataxia linked to T. whipplei that may be cured with antibiotics.

The many faces of hemifacial spasm: differential diagnosis of unilateral facial spasms

Hemifacial spasm is defined as unilateral, involuntary, irregular clonic or tonic movement of muscles innervated by the seventh cranial nerve. Most frequently attributed to vascular loop compression at the root exit zone of the facial nerve, there are many other etiologies of unilateral facial movements that must be considered in the differential diagnosis of hemifacial spasm. The primary purpose of this review is to draw attention to the marked heterogeneity of unilateral facial spasms and to focus on clinical characteristics of mimickers of hemifacial spasm and on atypical presentations of nonvascular cases. In addition to a comprehensive review of the literature on hemifacial spasm, medical records and videos of consecutive patients referred to the Movement Disorders Clinic at Baylor College of Medicine for hemifacial spasm between 2000 and 2010 were reviewed, and videos of illustrative cases were edited. Among 215 patients referred for evaluation of hemifacial spasm, 133 (62%) were classified as primary or idiopathic hemifacial spasm (presumably caused by vascular compression of the ipsilateral facial nerve), and 4 (2%) had hereditary hemifacial spasm. Secondary causes were found in 40 patients (19%) and included Bell's palsy (n=23, 11%), facial nerve injury (n=13, 6%), demyelination (n=2), and brain vascular insults (n=2). There were an additional 38 patients (18%) with hemifacial spasm mimickers classified as psychogenic, tics, dystonia, myoclonus, and hemimasticatory spasm. We concluded that although most cases of hemifacial spasm are idiopathic and probably caused by vascular compression of the facial nerve, other etiologies should be considered in the differential diagnosis, particularly if there are atypical features.

Nystagmus and saccadic intrusions

We review current concepts of nystagmus and saccadic oscillations, applying a pathophysiological approach. We begin by discussing how nystagmus may arise when the mechanisms that normally hold gaze steady are impaired. We then describe the clinical and laboratory evaluation of patients with ocular oscillations. Next, we systematically review the features of nystagmus arising from peripheral and central vestibular disorders, nystagmus due to an abnormal gaze-holding mechanism (neural integrator), and nystagmus occurring when vision is compromised. We then discuss forms of nystagmus for which the pathogenesis is not well understood, including acquired pendular nystagmus and congenital forms of nystagmus. We then summarize the spectrum of saccadic disorders that disrupt steady gaze, from intrusions to flutter and opsoclonus. Finally, we review current treatment options for nystagmus and saccadic oscillations, including drugs, surgery, and optical methods. Examples of each type of nystagmus are provided in the form of figures.

An introduction to dyskinesia--the clinical spectrum

The term movement disorder is used to describe a variety of abnormal movements, and may involve an excess or paucity of movement. Careful characterization of phenomenology is an essential component of diagnosis. Factors such as speed, amplitude, duration, distribution, rhythmicity, suppressibility and pattern of movement provide valuable information to guide the clinician in their assessment of the movement disorder. In this chapter, the clinical spectrum and phenomenology of dyskinesias will be reviewed.

The emerging link between autoimmune disorders and neuropsychiatric disease

Abnormal autoimmune activity has been implicated in a number of neuropsychiatric disorders. In this review, the authors discuss a newly recognized class of synaptic autoimmune encephalitides as well as behavioral and cognitive manifestations of systemic autoimmune diseases.

MR imaging of central nervous system Whipple disease: a 15-year review

CNS WD is fatal if antibiotics are not begun early, but knowledge regarding the variety of presentations on MR imaging is limited. In order to more effectively recognize this entity on MR imaging, the Mayo Clinic medical records were reviewed for subjects diagnosed with CNS WD from 1992-2006 who had also undergone MR imaging of the neuraxis. Seven subjects were identified and their imaging findings were reviewed by the authors. Four of 7 had head MR imaging findings indicative of WD. Two subjects demonstrated high T2 signal within the corticospinal tracts. CNS WD may demonstrate high T2 signal with minimal enhancement and no restricted diffusion, primarily in the midline of the midbrain, hypothalamus, and mesial temporal lobes and occasionally the corticospinal tracts. MR imaging may also be normal. Radiologists should be aware of these presentations and be prepared to mention CNS WD as a diagnostic possibility since early antibiotic therapy may significantly impact morbidity and mortality.

Whipple's disease: a rare disease revisited

Since the original postmortem diagnosis of "intestinal lipodystrophy" by Dr. George H. Whipple in 1907, the complexities of Whipple's disease have been elucidated through case reports. Universally fatal prior to the advent of antibiotics, Tropheryma whipplei is increasingly recognized as an organism that can be treated only if the clinician seeks to identify it. Whipple's disease is primarily a gastrointestinal disease manifesting as a malabsorption syndrome, and is detected through endoscopy and intestinal biopsy. Nongastrointestinal manifestations of the disease, although less common, are reported and have aided in its recognition as a multiorgan disease entity. Because of its rarity, treatment recommendations are currently based on observational studies and on one recent prospective study, which outlined induction therapy followed by several months of suppressive maintenance therapy to prevent relapse, which is often characterized by neurologic symptoms.

Whipple disease of the central nervous system: an unusual occurrence in association with acquired immune deficiency syndrome

Whipple disease is a multisystem infectious disease caused by Tropheryma whippleii. It commonly affects the CNS and produces neurological symptoms in 10–20% of cases. Central nervous system Whipple disease occurring in patients with AIDS is extremely rare. The authors present a case of a newly diagnosed AIDS patient in whom intracranial Whipple disease was diagnosed by stereotactic brain biopsy.

The distinctive movement disorder of ovarian teratoma-associated encephalitis

The movement disorder observed in four cases of ovarian teratoma associated encephalitis is described. The illness began with neuropsychiatric symptoms and was followed by prolonged unresponsiveness, respiratory failure, and autonomic instability. The movement disorder consisted of semirhythmic repetitive bulbar and limb movements and persisted during prolonged periods of unresponsiveness, diminishing as awareness returned. The characteristics of the movement disorder differed from recognized dyskinesias. It is suggested that interruption of forebrain corticostriatal inputs by anti-N-methyl-D-aspartate (NMDA) receptor antibodies removes tonic inhibition of brainstem pattern generators releasing primitive patterns of bulbar and limb movement. Recognition of the distinctive movements should prompt a search for an ovarian teratoma since the condition is responsive to tumor resection and immunomodulation.