Geriatric Neurology

Three principles distinguish the neurologic assessment of older patients. First, and most important, people accumulate more diseases the longer they live. Second, some diseases occur primarily in the elderly. Third, even in the absence of any apparent disease, some components of the aging nervous system gradually deteriorate. As a consequence, older patients often have numerous symptoms referable to more than one organ system. The standard approach of trying to localize all symptoms to a single lesion is untenable in many cases. Instead, the question is whether the patient has a degenerative disease affecting sites distributed diffusely throughout the nervous system or a combination of unrelated diseases. The neurologic examination provides useful information for answering this question, but accurate interpretation of the examination requires knowledge of the changes that occur during normal aging.

Incontinence

Incontinence is a particularly distressing symptom for patients and their families, and this would be reason enough to evaluate it promptly. In addi- tion, although incontinence is not an emergency in and of itself, it some- times indicates the presence of an underlying neurologic condition that must be addressed urgently. Neurologic conditions more often produce urinary incontinence than fecal incontinence, and when both occur, urinary incontinence generally appears first.

Headache

Headaches can occur independently of any other disease processes (primary headache disorders) or they can be associated with a wide variety of underlying neurologic and systemic conditions (secondary headache disorders). The pathophysiologic mechanisms are incompletely under- stood. Most research has focused on migraine headaches, with the tacit assumption that other headache syndromes, both primary and secondary, have similar mechanisms.

Sleep Disorders

Sleep consists of a highly patterned sequence of cyclic activity in various regions of the brain; it is not simply a state of temporary unconsciousness. Although the brain is less responsive than normal during sleep, it is not totally unresponsive. In fact, during sleep the brain responds more readily to meaningful stimuli. Rapid eye movement (REM) sleep can be characterized as a period when the brain is active and the body is paralyzed, whereas in nonrapid eye movement (NREM) sleep, the brain is less active but the body can move. Sleep disorders are grouped into three general categories, based on whether patients have trouble staying awake, trouble sleeping, or abnormal behaviors during sleep.

Visual Symptoms

An accurate description of visual symptoms is the key to diagnosis. Patients with static or progressive deficits can be examined while symptoms are present. It is helpful to instruct patients that if they have more episodes in the future they should cover each eye in turn during the episodes and pay careful attention to how this affects their symptoms.

Acute Mental Status Changes

Acute mental status changes can be either focal (such as aphasia, neglect, or visual hallucinations) or diffuse (such as delirium or stupor).

Multifocal Central Nervous System Disorders

Most systemic illnesses, neuromuscular diseases, dementing illnesses, movement disorders, and sleep disorders affect the nervous system diffusely. Still, even these diffuse conditions possess some pattern and symmetry. The particular pattern of involvement is generally the basis for making a diagnosis. Unlike focal lesions and diffuse processes, multifocal conditions are characterized primarily by the lack of a consistent pattern.

Movement Disorders

The term “movement disorder” refers to a heterogeneous group of conditions that result in abnormal form or timing of voluntary movement in individuals with normal strength and sensation. Movement disorders can be grouped into three general categories, hypokinetic, hyperkinetic, and ataxic. Hypokinetic movement disorders are characterized by tremors. Hyperkinetic movement disorders are characterized by involuntary movements that intrude into the normal flow of motor acts. Ataxic movement disorders are characterized by a lack of speed and skill in performing acts requiring the smoothly coordinated activity of several muscles.

Dementing Illnesses

Dementia is defined as an acquired, persistent decline of intellectual function that causes impaired performance of daily activities, without clouding of the sensorium or underlying psychiatric disease. The decline must involve at least two of the following domains: (a) ability to learn and remember new information, (b) reasoning and judgment, (c) visuospatial perception, (d) language function, and (e) personality and behavior. Patients who have experienced an episode of brain dysfunction from a wide variety of causes may be left with significantly impaired cognitive function that subsequently remains stable or improves. These nonprogressive dementias do not present the same diagnostic or management issues as the progressive dementias.

Stroke

This chapter focuses on the primary causes and preventions of stroke. Ischemic stroke occurs when a localized area in the nervous system is deprived of glucose and oxygen because of inadequate cerebral blood flow. The severity of injury is a function of how much the blood flow has been reduced and for how long. In most cases, strokes can be diagnosed purely on the basis of the history and examination. After a stroke occurs, it will continue to manifest as a region of impeded diffusion (also referred to as “restricted diffusion”) on MRI for about two weeks, but MRI scans are unnecessary when the history and examination provide compelling evidence of a stroke and the mechanism of stroke is apparent. Some studies have shown that early rehabilitation allows stroke patients to recover more quickly and perhaps to a higher level of function. Stroke prevention will continue to be the cornerstone of stroke management. Primary prevention is directed toward the early recognition and treatment of risk factors that predispose to the development of cerebrovascular disease.