Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Cranial Neuropathies

Olfactory Nerve (Cranial Nerve I) See Chapter 19 . Optic Nerve (Cranial Nerve II) See Chapter 16, Chapter 43 . Oculomotor Nerve (Cranial Nerve III) Anatomy Paired oculomotor nuclei are located in the dorsal midbrain ventral to the periaqueductal gray matter at the level of the superior colliculus. Each nucleus is composed of a superior rectus subnucleus providing innervation to the contralateral superior rectus; inferior rectus,…

Headache and Other Craniofacial Pain

Pain Transmission and Modulation as Related to Headache Headache arises from activation of pain-sensitive intracranial structures. In the 1930s, Ray and Wolff identified which intracranial components were pain sensitive and mapped the pattern of pain referral based on studies in which various intracranial structures were stimulated during intracranial surgery performed during local anesthesia. Intracranial pain-sensitive structures include the arteries of the circle of Willis and the…

Sleep and Its Disorders

Since antiquity, scientists, philosophers, writers, and religious scholars from all cultures and continents have repeatedly raised two fundamental questions—(1) what is sleep? and (2) why do we sleep?—without satisfactory answers. Some 2000 years ago, Lucretius postulated that sleep is an absence of wakefulness. Macnish, in 1830, proposed a variation of Lucretius’s concept, defining sleep as “suspension of sensorial power in which the voluntary functions are absent…

Epilepsies

Seizures and Epilepsy Definitions Seizures are transient events that include symptoms and/or signs of abnormal excessive hypersynchronous activity in the brain ( ). The traditional definition of epilepsy required the occurrence of two unprovoked seizures. It is known that the risk of seizure recurrence after two unprovoked seizures is greater than 60% ( ), and treatment would normally be initiated with an antiseizure medication (ASM) in…

Neurocutaneous Syndromes

Neurocutaneous disorders are congenital or hereditary conditions that feature lesions of both the skin and nervous system. Although each condition, or phakomatosis , is distinct and characterized by a unique pathophysiology, the concept of neurocutaneous disorders unifies those neurological disorders, whose identification depends primarily on simple visual diagnosis. These disorders may be inherited or sporadic; some of the sporadic disorders result from somatic mosaicism. Advances in…

Channelopathies: Episodic and Electrical Disorders of the Nervous System

Channelopathies are disorders caused by ion channel dysfunction. Because of the great diversity of ion channel proteins and their expression in different tissues, channelopathies comprise a wide variety of clinical diseases ( Table 98.1 ), the discovery of which helps elucidate how ion channels function in both illness and health. The periodic paralyses —the first group of ion channel disorders characterized at a molecular level—defined the…

Disorders of Upper and Lower Motor Neurons

It is important for the practicing clinician to make the distinction between the term motor neuron disease (MND) and motor neuron diseases (MNDs). The intention of the first term, coined by Brain in 1969, is to refer to a specific disorder of both upper and lower motor neurons, otherwise known as amyotrophic lateral sclerosis (ALS). The second term refers to the broader family of disorders that…

Parkinson Disease and Other Movement Disorders

Movement Disorders and the Basal Ganglia Neurologists often equate movement disorders with disease or dysfunction of the basal ganglia, so no review of movement disorders would be complete without a discussion of these subcortical structures and their connections. In some movement disorders such as parkinsonism, chorea, and ballism, the link to the basal ganglia is supported by clinicopathological, biochemical, functional neuroimaging, and electrophysiological data, whereas in…

Alzheimer Disease and Other Dementias

Normal Aging and Mild Cognitive Impairment Normal Aging A cognitive continuum exists from normal aging through mild cognitive impairment (MCI) to dementia. This continuum is better understood when realizing that it occurs on a background of some degree of cognitive decline with aging. While the theoretical ideal is to age without cognitive change, typically cognitive function declines over time. Research has provided normative data on cognitively…

Prion Diseases

Prion (pronounced pree-ahn ) diseases (PrDs) are a group of uniformly fatal neurodegenerative diseases caused by the transformation of an endogenous protein, PrP (prion-related protein), into an abnormal conformation (misfolded protein) called the prion . The term prion is derived from the term proteinaceous infectious particle and was named by Stanley Prusiner, who discovered prions ( ). For many years, prion diseases were mistakenly thought to…

Mitochondrial Disorders

The bacterial hypothesis of the origin of mitochondria suggests that approximately 1–2 billion years ago, alpha-purple bacteria were incorporated into evolving eukaryotic cells. During evolution, these bacteria transferred many of their essential genes to the nuclear chromosomes. Mitochondria still have many remnants of their bacterial origin, such as the use of N -formylmethionyl-tRNA (transfer ribonucleic acid) as the initiator of protein synthesis. Our current knowledge of…

Neurodegenerative Disease Processes

Acknowledgments We thank Dr. Aviva Tolkovsky for her critical review of the original manuscript and Dr. Janelle Drouin-Ouellet for her help with the figure. Neurodegenerative disorders of the central nervous system (CNS) are characterized by the loss of specific populations of neural cells, the pattern and distribution of which shape the clinical presentation of the patient. This has led to the standard way in which these…

Inborn Errors of Metabolism and the Nervous System

Acknowledgment This chapter, updated from the prior edition, was originally a revised version of the chapter by G.M. Pastores in the sixth edition. The concept of inborn errors of metabolism (IEM) was introduced by Sir Archibald Garrod in the 1908 Croonian Lectures, and further developed in his Huxley Lecture presented at Charing Cross Hospital in London ( ). IEM constitute a heterogeneous group of disorders resulting…

Autism and Other Neurodevelopmental Disabilities

Autism Spectrum Disorders Diagnostic Criteria Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in two areas: (1) deficits in social communication and social interactions; and (2) restricted and repetitive patterns of behavior, interests, and activities ( ). With the revised Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), ASD now subsumes what were previously separate diagnostic categories of autistic disorder (also…

Developmental Disorders of the Nervous System

Embryological and Fetal Development of the Nervous System Neuroembryology integrated with molecular genetics provides the key to understanding congenital malformations of the nervous system. Modern neuroembryology or ontogenesis encompasses not only classical descriptive morphogenesis but also the molecular genetic programming of development and the immunocytochemical demonstration of maturation of neuronal and glial proteins in individual cells and sequences of neurotransmitter biosynthesis, synapse formation, and myelination. Neuroimaging…

Brain Edema and Disorders of Cerebrospinal Fluid Circulation

Acknowledgments The neuroradiological illustrations were generously provided by Blaine Hart, MD, Department of Radiology (Neuroradiology), University of New Mexico Health Sciences Center. Brain Edema and Disorders of Cerebrospinal Fluid Circulation Increased intracranial pressure (ICP) and cerebral edema are life-threatening complications of shifts in water between cells and tissue that are final common pathways of injury in many neurological disorders. Separation of brain fluids from blood is…

Effects of Drug Abuse on the Nervous System

Drug dependence is of two types. Psychic dependence (addiction) refers to craving and drug-seeking behavior. Physical dependence refers to an adaptive state in which abrupt cessation of drug use results in somatic withdrawal symptoms. Tolerance refers to the need for increasing doses of a drug to produce a desired effect or to avoid withdrawal. Abuse refers to the perception that use of a drug, or the…

Effects of Toxins and Physical Agents on the Nervous System

Neurotoxic disorders are occurring increasingly as a result of occupational or environmental exposure and often go unrecognized. Exposure to neurotoxins may lead to dysfunction of any part of the central, peripheral, or autonomic nervous system and the neuromuscular apparatus. Neurotoxic disorders are recognized readily if a close temporal relationship exists between clinical onset and prior exposure to an agent, especially one known to be neurotoxic. Known…

Deficiency Diseases of the Nervous System

Malnutrition causes a wide spectrum of neurological disorders ( Table 85.1 ) . Despite socioeconomic advances, nutritional deficiency diseases such as kwashiorkor and marasmus are still endemic in many underdeveloped countries. The problem in Western countries is usually the result of dietary insufficiency from chronic alcoholism or malabsorption due to gastrointestinal (GI) diseases. Bariatric surgery has become an important risk factor of malabsorption due to its…

Toxic and Metabolic Encephalopathies

Toxic and metabolic encephalopathies are a group of neurological disorders characterized by an altered mental status—that is, a delirium , defined as a disturbance of consciousness characterized by a reduced ability to focus, sustain, or shift attention that cannot be accounted for by preexisting or evolving dementia and that is caused by the direct physiological consequences of a general medical condition (see Chapter 4 ). Fluctuation…