Figure 14-3. A simplified diagram of the vestibulocerebellar and vestibulospinal pathways and connections between vestibular and ocular motor nuclei. The medial longitudinal fasciculi (blue lines) are the main pathways for ascending vestibular impulses. (See text and also Fig. 14-1.)
Figure 14-4. The vestibular reflex pathways. (Reproduced by permission from House EL: A Systematic Approach to Neuroscience. New York, McGraw-Hill, 1979.)
Figure 14-5. Dix-Hallpike maneuver to elicit benign positional vertigo (originating in the right ear). A. The maneuver begins with the patient seated and the head turned to one side at 45 degrees, which aligns the right posterior semicircular canal with the sagittal plane of the head.
B. The patient is then helped to recline rapidly so that the head hangs over the edge of the table, still turned 45 degrees from the midline. Within several seconds, this elicits vertigo and nystagmus that is right beating with a rotary (counterclockwise) component. An important feature of this type of “peripheral” vertigo is a change in the direction of nystagmus when the patient sits up again with his head still rotated. If no nystagmus is elicited, the maneuver is repeated after a pause of 30 s, with the head turned to the left. Treatment with the canalith repositioning maneuver is shown in Fig. 14-6.
Figure 14-6. Bedside maneuver for the treatment of a patient with benign paroxysmal positional vertigo affecting the right ear. The presumed position of the debris within the labyrinth during the maneuver is shown on each panel. The maneuver is a four-step procedure. First, a Dix-Hallpike test is performed with the patient’s head rotated 45 degrees toward the (affected) right ear and the neck slightly extended with the chin pointed slightly upward. A. This position results in the patient’s head hanging to the right. B. Once the vertigo and nystagmus provoked by this maneuver cease, the patient’s head is rotated about the rostral–caudal body axis until the left ear is down. C. Then the head and body are further rotated until the head is almost facing down. The vertex of the head is kept tilted upward throughout the rotation. The patient should be kept in the final, face down position for about 10 to 15 s. D. With the head kept turned toward the left shoulder, the patient is brought into the seated position.
Chapter  14    Deafness, Dizziness, and Disorders of Equilibrium
Chapter 16  Coma and Related Disorders of Consciousness
The prevalence and importance of epilepsy, recurrent unprovoked seizures, can hardly be overstated. From the epidemiologic studies of Hauser and colleagues, one may extrapolate an incidence of approximately 2 million individuals in the United States who have epilepsy and predict about 44 new cases per 100,000 persons each year. These figures are exclusive of patients in whom seizures transiently complicate febrile and other illnesses or injuries. It has also been estimated that slightly less than 1 percent of persons in the United States will have epilepsy by the age of 20 years (Hauser and Annegers). Over two-thirds of all epileptic seizures begin in childhood (most in the first year of life), and this is the period when seizures assume the widest array of forms. In the practice of pediatric neurology, epilepsy is one of the most common disorders, and the chronicity of childhood forms adds to their importance. The incidence increases again after age 60 years. For all these reasons, physicians should know something of the nature of seizure disorders and their treatment. It is notable that, in striking contrast to the many treatments available for epilepsy, as pointed out by J. Engel, 80 to 90 percent of persons with epilepsy in the developing world never receive medical attention.