Introduction Gait is a fundamental human skill. It permits movement from place to place, and, as anthropologists are fond of pointing out, that humans do it on two legs frees up the arms for other skilled tasks. The ability to walk is basic to human quality of life. However, walking on two legs is a difficult motor task involving the ability to balance and execute a…

Introduction Literally, myoclonus means “a quick movement of muscle.” Sudden, brief jerks may be caused not only by active muscle contractions, positive myoclonus, but also by sudden, brief lapses of muscle contraction in active postural muscles, negative myoclonus or asterixis ( ). The history of myoclonus has been described by , , and . Friedreich first defined myoclonus as a discrete entity in a case report…

Introduction The topic of tardive dyskinesia (TD) syndromes is very broad, covering different phenomenologies. There have been several recent reviews written on this topic, but most research has focused on new treatments ( ; ; ; ; ; ). This chapter will cover tardive and nontardive neuroleptic-induced movement disorders, further extending the scope of material to review. Because of the volume of material to cover, the…

Introduction Stereotypies may be defined as involuntary or unvoluntary (in response to or induced by inner sensory stimulus or unwanted feeling), coordinated, patterned, repetitive, rhythmic, seemingly purposeless movements or utterances ( , ; ; ; ). Although each child tends to have his or her own repertoire of movements, typical motor stereotypies include body rocking, head nodding, head banging, hand waving, covering ears, fluttering of fingers…

Introduction Tourette syndrome (TS), which should be more appropriately called Gilles de la Tourette syndrome, is a neurologic disorder manifested by motor and vocal or phonic tics starting during childhood and often accompanied by obsessive-compulsive disorder (OCD), attention deficit–hyperactivity disorder (ADHD), poor impulse control, and other comorbid behavioral problems ( ; ; ; ; ). Once considered a rare psychiatric curiosity, TS is now recognized as…

Introduction Chorea consists of involuntary, continual, abrupt, rapid, brief, unsustained, and irregular movements that flow randomly from one body part to another. Patients can partially and temporarily suppress the chorea and frequently camouflage some of the choreiform movements by incorporating them into semipurposeful activities (parakinesia). The inability to maintain voluntary contraction (motor impersistence), such as manual grip (milkmaid grip) or tongue protrusion, is a characteristic feature…

Introduction George Huntington published his essay “On Chorea” in 1872 (Huntington, 1872), 1 year after graduating from Columbia College of Physicians and Surgeons and while practicing general medicine with his father on Long Island, New York. In this paper, he described many of the clinical features associated with the entity later to carry his name. These features included onset in adulthood, hereditary nature, presence of abnormal…

Introduction Despite paucity of knowledge about the cause and pathogenesis of dystonic disorders, the symptomatic treatment of dystonia has markedly improved, particularly since the introduction of botulinum toxin (BoNT). In most cases of dystonia, the treatment is merely symptomatic, designed to improve posture and function and relieve associated pain. In rare patients, however, dystonia can be so severe that it can produce not only abnormal postures…

In the course of the last 5 years I have repeatedly observed an affliction, whose meaning and classification caused great difficulties. When examining the first cases I was trying to decide between a diagnosis of hysteria, and idiopathic bilateral athetosis; but then I soon realized that neither of these diagnoses was appropriate, and that this was a new condition, or at least a new type of…

Introduction Tremor is a rhythmic, oscillatory movement produced by alternating or synchronous contractions of antagonist muscles. It is the most common form of involuntary movement, but only a small fraction of those who shake seek medical attention. Indeed, in one epidemiologic study of normal controls, 96% were found to have clinically detectable postural tremor and 28% had a postural tremor of “moderate amplitude” ( ). Tremors…

Introduction Parkinsonism is a dominant or an important clinical feature in a large number of neurodegenerative disorders ( ; ; ). Most patients who are referred to specialized movement disorder clinics with hypokinetic disorders are diagnosed clinically as having Parkinson disease (PD); others have a variety of parkinsonian disorders, including (in descending order of frequency, vascular parkinsonism (VP), progressive supranuclear palsy (PSP), multiple system atrophy (MSA),…

Introduction Although the motor symptoms of Parkinson disease (PD) dominate the clinical picture—and even define the parkinsonian syndrome—many patients with PD have other complaints that have been classified as nonmotor ( ), and several recent scales have been developed to quantify these symptoms ( ). The Unified Parkinson’s Disease Rating Scale (UPDRS) has been recently modified by the Movement Disorders Society (MDS) to include more nonmotor…

Introduction A variety of surgical treatments for Parkinson’s disease (PD), including ablation or deafferentation of motor and premotor cortex, cervical cordotomy, and mesencephalic pedunculotomy, were performed in the first five decades of the twentieth century ( ). These procedures generally yielded relief of the movement disorder at the expense of concomitant weakness and other complications. Surgery at the level of the basal ganglia for PD was…

Introduction The clinical symptoms and signs of Parkinson disease (PD) can be conveniently divided into motor and nonmotor features, necessitating individualization of therapy tailored to each patient’s needs ( ). Although the nonmotor aspects of PD can be equally incapacitating for people with PD, it is the motor component that defines the disease, for without the motor component, the diagnosis cannot be established. This chapter focuses…

Anatomical and biochemical pathologic processes of PD Historical introduction Parkinson disease (PD) was first described in 1817 with the publication by James Parkinson of a small book entitled An Essay on the Shaking Palsy ( ). In it, he described six individuals with the clinical features that have come to be recognized as a disease entity. One of the people was followed in detail over a…

Introduction Parkinsonism is a syndrome manifested by a combination of the following six cardinal motor features: tremor-at-rest, rigidity, bradykinesia, loss of postural reflexes, flexed posture, and freezing (motor blocks). A combination of these signs is used to clinically define definite, probable, and possible parkinsonism ( Table 4.1 ). The most common form of parkinsonism is the idiopathic variety known as Parkinson disease (PD), first recognized as…

Introduction The basal ganglia comprise a collection of nuclear structures deep in the brain and have been defined anatomically and functionally. Anatomically, the basal ganglia are the deep nuclei in the telencephalon. Functionally, three closely associated structures, the subthalamic nucleus (STN) (in the diencephalon), the substantia nigra (SN), and pedunculopontine nucleus (PPN) (both in the mesencephalon), are also included as part of the motor part of…

Movement, whether voluntary or involuntary, is produced by the contraction of muscle. Muscle, in turn, is normally controlled entirely by the anterior horn cells or alpha motoneurons. An anterior horn cell with its innervated muscle fibers is called the motor unit. Some involuntary movement disorders arise from muscle, the alpha motoneuron axon, or the alpha motoneuron itself. Although this territory might be considered neuromuscular disease, the…

To study the phenomenon of disease without books is to sail an uncharted sea, while to study books without patients is not to go to sea at all. Sir William Osler Fundamentals The quotation from Sir William Osler in 1901 at the dedication ceremony for a new building of the Boston Medical Library (cited by ) is an apt introduction to this chapter, which offers a…