Staab, Jeffrey P

Abstract Introduction Alice in Wonderland Syndrome (AIWS) is an uncommon condition manifesting visual and somatosensory disturbances in which patients may perceive objects, including their own bodies, as larger or smaller than they are. In adults, AIWS typically is associated with migraine and epilepsy but has been reported as an adverse effect of topiramate, which is used to treat both illnesses, making it difficult to ascertain whether illness or medication causes altered perceptions. Reported is a case of topiramate-associated AIWS, which adds to the limited reports published on this unique phenomenon. Case Report A 40-year-old woman admitted to a 3-week pain rehabilitation program to treat chronic migraine reported macrosomatognosia that she retrospectively recalled beginning during titration of topiramate. The symptoms of AIWS resolved after the topiramate was discontinued. An assessment with the Naranjo ADR Probability Scale indicated a possible association between topiramate and macrosomatognosia. Discussion In this patient with migraine, the onset of AIWS coincided with titration of topiramate, providing a clue that its emergence may have been an adverse drug reaction rather than the underlying illness. Consistent with previous reports, AIWS resolved shortly after topiramate was discontinued, lending credence to this conclusion. However, the mechanism of AIWS is unknown and may be multifactorial, leaving the possibility that migraine predisposed the patient to develop AIWS from topiramate. Conclusion The long association of AIWS with migraine and epilepsy makes it possible that cases caused by medications used to treat these illnesses, like topiramate, are underreported. Awareness of the temporal relationships between the course of illness and the timing of drug therapy can help guide the recognition of AIWS as a potential adverse event.

In 2007, the Bárány Society embarked on a project to establish definitions of vestibular syndromes and disorders based on best available evidence, referred to as the International Classification of Vestibular Disorders (ICVD). Since then, numerous publications providing consensus-driven diagnostic criteria for vestibular symptoms, syndromes, and disorders have been published. Here, we reflect on the rationale for developing the ICVD as well as its subsequent achievements, challenges, and outlook. In this summary of the work of the ICVD to date, the authors will focus on practical aspects to help improve the utility and applicability of these diagnostic criteria moving forward.

A growing body of clinical and epidemiological evidence supports a specific relationship between vestibular symptoms and migraine. Without a biomarker or complete understanding of pathophysiology, diagnosis of vestibular migraine (VM) currently depends upon symptoms in two dimensions: episodic vestibular symptoms temporally related to migraine symptoms. The Bárány Society and the International Headache Society have recently developed consensus diagnostic criteria. However, many issues remain unsettled, including the type, duration, and timing of vestibular symptoms related to headache that should be required for diagnosing VM. This paper focuses on the challenging third dimension of comorbidity, a frequent cause of diagnostic uncertainty that may confound clinical application and research validation of VM criteria. Several other neurotologic conditions occur more frequently in migraineurs than controls, including benign paroxysmal positional vertigo, Ménière's disease, and motion sickness. Patients with VM also have high rates of chronic subjective dizziness, which may be associated with anxious, introverted temperaments that can affect clinical presentation and treatment response. Broadly inclusive studies of well-characterized patients with other neurotologic and psychiatric comorbidities are needed to fully understand how vestibular symptoms and migraine interact in order to truly validate vestibular migraine, distill its essential features, define its boundaries, and characterize overlapping comorbidities.

Recent years have witnessed an upsurge of interest in migraine as a cause of vestibular symptoms. Starting with 1970s case reports linking migraine to childhood vertigo, neurotologists worldwide have increasingly diagnosed migraine. Various syndromes of vestibular migraine (VM) have been described, diagnostic criteria proposed, epidemiologic data collected, and neurophysiologic models developed. Yet, the concept that migraine causes vestibular symptoms rests on a surprisingly thin research database. Current concepts of VM are based on expert opinion, not empirical data. No general consensus exists about the definition of VM. No studies have analyzed its essential features. Just one well-controlled medication trial has been published. No biomarkers are known. To stimulate more rigorous research, this paper poses three questions about clinical investigations into migraine and vestibular symptoms: What variables should be measured? What patients should be studied? How might clinical trials yield both clinically useful results and greater insights into pathophysiologic processes? Using these questions, the limits of current knowledge are explored. Applicable research methods from epidemiology to genetics are examined. Pilot data demonstrating pharmacologic and genetic dissection techniques are presented. Ambitious, but practical, near-term clinical research goals are enumerated, including rigorous validation of diagnostic criteria and development of empirically derived management guidelines.

Persistent postural-perceptual dizziness (PPPD) is a newly defined diagnostic syndrome that unifies key features of chronic subjective dizziness, phobic postural vertigo and related disorders. It describes a common chronic dysfunction of the vestibular system and brain that produces persistent dizziness, non-spinning vertigo and/or unsteadiness. The disorder constitutes a long-term maladaptation to a neuro-otological, medical or psychological event that triggered vestibular symptoms, and is usefully considered within the spectrum of other functional neurological disorders. While diagnostic tests and conventional imaging usually remain negative, patients with PPPD present in a characteristic way that maps on to positive diagnostic criteria. Patients often develop secondary functional gait disorder, anxiety, avoidance behaviour and severe disability. Once recognised, PPPD can be managed with effective communication and tailored treatment strategies, including specialised physical therapy (vestibular rehabilitation), serotonergic medications and cognitive-behavioural therapy.

Purpose of review Functional dizziness is the new term for somatoform or psychogenic dizziness. The aim of this study is to review arguments for the new nomenclature, clinical features, possible pathomechanisms, and comorbidities of functional dizziness. Recent findings The prevalence of functional dizziness as a primary cause of vestibular symptoms amounts to 10% in neuro-otology centers. Rates of psychiatric comorbidity in patients with structural vestibular syndromes are much higher with nearly 50% and with highest rates in patients with vestibular migraine, vestibular paroxysmia, and Ménière's disease. Pathophysiologic processes seem to include precipitating events that trigger anxiety-related changes in postural strategies with an increased attention to head and body motion and a cocontraction of leg muscles. Personality traits with high levels of neuroticism and low levels of extraversion appear as risk factors for anxiety and depressive disorders and increased morbidity in functional disorders. Summary Correct and early diagnosis of functional dizziness, as primary cause or secondary disorder after a structural vestibular syndrome, is very important to prevent further chronification and enable adequate treatment. Treatment plans that include patient education, vestibular rehabilitation, cognitive and behavioral therapies, and medications substantially reduce morbidity and offer the potential for sustained remission when applied systematically.