Ta ble 9 .14 Differentiation of peripheral and central vestibular disturbances Test Peripheral (lesiononthe right) Central Nystagmus Rapid component to the left May be vertical, rotatory, or dissociated(i.e.,onlydetect- able in one eye in particular positions); may be accompa- nied by otherbrainstem signs Excitability of laby- rinth Diminished or none on right Normal Other Romberg test: fall to right Walking a straight line: deviationtoright Unterberger stepping test: more than 45% turn to right after 40 steps Arm position test: deviationtoright B´ar´any pointing test: past- pointing to right These tests yield variable and often mutually inconsistent findings with respect to late- rality and direction (so-called “dysharmonie vestibulaire”) tion (cf. positional nystagmus, p. 695). The various types of nystag- mus and their localizing significance are described on p. 643. The features thatdistinguish central from peripheral vestibular disorders are important to know and are sum- marized in Table 9.14. Various tests of stance and gait are useful in the demonstration of ve stib- ular disturbances (and other types of disturbances causing dysequilib- rium), particularly the Unterberger step test and the Babinski-Weil walk- ing test. In the B´ar´any pointing test (see Fig. 9.31), the patient extends his arms and points with his index f in- gers to the examiner’s index fingers. He is then asked to close his eyes and advance his index fingers straight for- ward to touch the examiner’s fingers. In the presence of a vestibular lesion, the patient’s fingers deviate to the side of the lesion. The brain has multiple sources of in- formation that help it to maintain the body’s balance and orientation in space (Figs. 9.27,9.28): the vestibular apparatus, the visual system, and the proprioceptive system (in which im- pulses from the peripheral nerves are relayed to t he sp inal cord and upward to the cerebellum. If one of these sys- tems should cease tofunction,the body can remain inbalance, but if two or all three cease to function, dy- sequilibrium arises. Patients experi- ence this as unsteady gait, subjective imbalance, and vertigo. Information from the vestibular, vi- sual, and proprioceptive systems con- verges in the central nervous system, where it is integrated and determines the motor response that regulates 692 9DiseasesAffecting the Cranial Nerves Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. Visual system, eye movements Brainstem Cerebellum Labyrinth Spinal cord, peripheral nervous system Pyramidal and extrapyramidal motor system Vestibular nuclei Fig. 9.28 Maintenance of balance by integra- tion of information from multiple channels. muscle tone and body posture. A ma- jor role is played by reciprocal connec- tions between the visual and vestibu- lar systems and by motor control of the eyes and head, which depends on the normal functioning of the cerebel- lum and cerebral cortex (see also ocu- lar motility, p. 634). If all of the infor- mation converging on the CNS is con- sistent with prior experience, it is pro- cessed without reaching the level of consciousness, and the individual re- mains unaware of it. If, however, infor- mation arrives that is inconsistent with prior experience, an unpleasant sensation generally arises, namely, vertigo. (This is anoutlineof the so- called mismatch hypothesis.) If this sensation persists, the individual feels unwell and begins to suffer from other vegetative phenomena such as nausea, diaphoresis, salivation, or vomiting. Physiologic vertigo. Individual expe- rience has trained the brain of each of us to expect a certain amount of shift in the retinal image of the environ- ment when we take a step forward. If we stand on top of a mountain or sky - scraper, the retinal image of the now very distant objects around us shifts much less than we are accustomed to when we move. As a result, we be- come nervous or dizzy (height dizzi- ness, acrophobia). This is one example of normal, physiologic vertigo; an- other is motion sickness, with its vari- ants carsickness and seasickness,in which unusual movement of the body creates a conflict between vi- sual and vestibular input, and thereby produces vertigo. Pathological vertigo. Temporary or persistent, functional or structural impairment of the vestibular, visual, or proprioceptive systems or of the central integrative mechanism also causes “mismatch” and, therefore, pathological vertigo. The diagnostic evaluation of vertigo has two pur- poses: localizing its site of origin and determining its etiology . Disturbances of the Vestibulocochlear Nerve 693 Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. Clinical History The patient’s spontaneous descrip- tion of vertigo is rarely precise enough to yield useful information for diagnosis. Thus, the clinician must know what specific questions to ask to bring the diagnostic process fur- ther. The most important points to be clarified are listed in Table 9.15. Historical Clues toDifferential Diagnosis The subjective quality of vertigo may already constitute strong evidence for or against a vestibular disturbance. Directional sensations such as rota- tion, a “carousel” feeling, lateropul- sion, or a feeling of being lifted are more likely to b e due to a vestibular lesion than such sensations as reel- ing, staggering, dazedness, quasi- drunkenness, lightheadedness, dark- ness before one’s eyes, or a feeling of emptiness. The duration of vertigo may point to a particular group of possible etiolo- gies. An attack duration of a few sec- onds is typical for all forms of posi- tional vertigo, minutes for vertebro- basilar TIA or migraine, hours for M´eni`ere’s disease, and days for vesti- bulopathies such as vestibular neuri- tis or labyrinthine infarction. Persis- tent vertigo is rarelyofvestibularori- gin. Positional vertigo occurs only in cer- tain positions of the head or body, or only during certain changes of posi- tion. Concomitant auditory symptoms indicate a peripheral vestibular etiol- ogy, while visual abnormalities indi- cate cortical pathology (in the case of diminished visual acuity or a field de- fect) or a brainstem process (in the case of diplopia). Accompanying vegetative distur- bances point to a peripheral vestibu- lar origin for vertigo, as such distur- bances are generally only mild in cen- tral vestibular or nonvestibular ver- tigo. Gait unsteadiness due to polyneuro- pathy or posterior column disease may be perceived by the patient as vertigo. This symptom worsens when the eyes are closed or in the dark, just as in the rarer case of a bilateral ves- tibular deficit. Characteristic of the latter is a perception of the environ- ment as b eing in motion – dancing or sliding away (oscillopsia,cf.p.646). Psychogenic vertigo,ofwhichthe most common type is phobic postural vertigo, should be suspected in pa- tients with obsessive-compulsive or hysterical personality traits com- bined with anxiety or phobias (agora- phobia, fear of falling, fear of death), and in patients complaining of situation-dependent vertiginous at- tacks (e.g., only on bridges or on stair- cases, while driving on the highway, etc.). Physical Examination of the Patient with Vertigo (298e) Pathologic nystagmus isthemostim- portant sign to b e looked for (cf. Ta- bles 9.5 and 9.13,andFig.9.16). As al- ready mentioned on p. 643, the ex- amination must b e carried out with the patient wearing Frenzel goggles, or in the dark with aninfrared device for visualization. Visual fixation could otherwise suppress vestibular nys- tagmus, producing falsely negative findings. Spontaneous vestibular nystagmus. This is characterized by a horizontal beat with a small torsional compo- 694 9DiseasesAffecting the Cranial Nerves Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. Ta ble 9 .15 Questions for history-taking in apatientcomplaining of dizziness Circumstances in which dizziness first arose? Quality of dizziness? Episodic or continuous? Single or multiple episodes? Duration of episode (seconds, minutes, hours, days)? In what bodily position(s) is dizziness worst? Do particular changes of position in- duce dizziness(bendingforward, lying down, turning in bed, looking up or down)? Auditory symptoms such as tinnitus, hearing loss, ear pain or pressure? Visual symptoms (blurring, diplopia, phosphenes)? Oscillopsia, spontaneous or induced by particular head positions? Effect of darkness or closing eyes on dizziness? Autonomic symptoms(nausea, vomit- ing, diaphoresis)? Situational dizziness (in a department store, in a crowd, on a staircase)? Neurologic symptoms, such as dyspha- gia, dysarthria, sensory disturbances on the faceorbody,or weakness of the face, arm, or leg? History of migraine? Medications? nent (see Fig. 9.16). It is provoked by gaze in the direction of the beat. It can be gradedintermsofseverity (Alexander grades I, II, and III). An at- tempt should alsobemadetopro- voke vestibular nystagmus by ma- neuvers such as shaking the head; any nystagmus produced in this way is abnormal and should be consid- ered a form of perhaps very mild spontaneous vestibular ny stagmus. Finally, the examiner should look for other forms of nystagmus, such as gaze-evoked, upbeat, downbeat, purely horizontal, or diagonal nystagmus, and note whether the beat is conju- gate o r dissociated. Positional nystagmus. Nystagmus may arise only when the head is in certain positions; as a typical exam- ple, when the head is positioned with the right ear down, there may be a nonfatigable, left-beating nystagmus. Note the rule of thumb that positional nystagmus ofthistypebeatstoward the higher ear, or, in equivalent terms, away from the ground – it is “ageotropic.” Positioning nystagmus. On the other hand, nystagmus may be present only transiently after a shift of position (cf. the above discussion of positional vertigo, p. 694). Nystagmus of this type must be sought with the Hall- pike maneuver, i llustrated in Fig. 9.29.Thepatientisshiftedfrom the sitting position to the supine po- sition with the head 30° downward and to the left or right. Nystagmus typically appears after a latency of a few seconds, increases in intensity over a few seconds, then diminishes and disappears. The patient simulta- neously experiences intense rotatory vertigo, perhapsaccompanied by nausea. The nystagmus is mainly ro- tatory, clockwise when the head is down and to the left and counter- clockwise when the head is down and to the right. Ifthepatientlooksto- Disturbances of the Vestibulocochlear Nerve 695 Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. a b Fig. 9.29a–e Positioning vertigo and nystagmus. The patient, wearing Frenzel goggles, is rapidly moved from the sitting position (a) to the supine position with the head hanging down and to the right (b)orleft(c). Po- sitioning vertigo manifests itself in counterclockwise ro- tating nystagmus when the head is down and to the right (d), clockwise rotating nystag- mus when the head is down and to the left (e). The nys- tagmus may beat vertically if the subject looks away from the floor. The intensity of nys- tagmus and vertigo first in- creases and then decreases within a few seconds. ward the floor, the nystagmus be- comes purely rotatory; if the patient looks at his own nose (away from the floor), it beats upward. This type of positioning nystagmus generally fa- tigues rapidly and can often be elic- ited only if the patient is allowed to rest for a while before the test is per- formed. Further T ests The normal suppression of vesti- bular nystagmus by visual fixation can be checked with the nystagmus suppression test (p. 643; see Fig. 9.15). Elicitation of vestibular nystagmus. Vestibular nystagmus isnormally symmetricallyelicitableand visible to the examiner when the patient, 696 9DiseasesAffecting the Cranial Nerves Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. Head down and to the ri g ht Head down and to the lef t c d, e Fig. 9.29c–e wearing Frenzel goggles, is rotated back and forth on a swivel chair. This test is not very sensitive, but any asymmetry or absence of nys- tagmus indicates uni- or bilateral vestibular pathology. Caloric vestibular testing provides a more sensitive indication of a ves- tibular deficit. The patient lies with the body and head rotated 30° from the supineposition,orelse sits up- right with the head tilted back 60°. If the left ear canal is then irrigated with 100–200 mL of water at room temperature, or 5–10 mL of ice wa- ter, h orizontal nystagmus normally appears, beating to the right. The patient points to the left on the B´ar´any pointing test(seebelow) and tends to fall to the left. Vertigo and nausea are simultaneously in- duced. Ir rigation with warm water (44°C) produces the opposite ef- fects. Absence of these reactions indicates that the labyrinth is un- excitable or that its connection to the brainstem is interrupted. Tym- panic perforation should always Disturbances of the Vestibulocochlear Nerve 697 Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. be ruled out by otoscopy before caloric testing is performed. Electronystagmography allows standardized evaluation of differ- ences between the caloric re- sponses of the right and left ears. It is even more informative when combined with the use of a computer-controlled swivel chair. The head thrust maneuver (Hal- magyi-Curthoys test) (376a) is used to test the oculovestibular re- flex in the horizontal plane and is thus a test of the horizontal semi- circular canal. The examiner rap- idly turns the patient’s head to one side while the patient looks at the examiner’s nose. The patient’s eyes should remain fixed on the exam- iner’s nose the entire time, includ- ing while the head is turning, be- cause the oculovestibular reflex is very f ast (p. 653). If the labyrinth is partially or totally dysfunctional, the eyes go along with the h ead as it is rotated, and, as soon as the head comes to a stop, a saccade brings the eyes back into fixation on the examiner’s nose (Fig. 9.30). If the right labyrinth is dysfunc- tional, the saccade is to the left af- ter a head t hrust to t he right;ifthe left labyrinth is dysfunctional, the saccade is to the right after a head thrust to the left. Walking with the eyes closed in the presence of a vestibular deficit re- sults in the appearance (or worsen- ing) of gait unsteadiness or a con- stant deviation to one side. The pa- tient is asked to walk toward the examiner from a distance of 5 m. This test is performed three times in succession. If there is an asym- metry of vestibular tone, the pa- tient’s gait will consistently deviate to one side. Care should be taken to eliminate brightness cues that the patient might see even with the eyes closed (e.g., the examiner should not stand in front of the window on a sunny day). Positional and pointing tests (Fig. 9.31)andUnterberger’s step- ping test can also reveal deviation to one side. In the Unterberger test, the patient walks in place for 1–3 minutes. Rotation or change of position is no more than slight in the normal situation, but marked if there is an asymmetry of vestibular tone. Threshold values for a posi- tive test are 1 m forward move- ment and 40–60° of rotation after 50 steps. The Babinski-Weil walking test is analogous to the above. The patient closes his eyes and walks repeat- edly two steps forward and two steps b ac kward; any rotation or lin- ear displacement implies a vestibu- lar deficit. Otoscopy and a complete neurologi- cal and general physicalexamina- tion complete the work-up. The ex- aminer should remember to mea- sure the blood pressure in both arms, and with the patient lying and sitting, to rule out vascular presyncope due to orthostatic hy- potension or subclavian steal syn- drome (p. 554). Patients with oscillopsia depending on head position or whose vertigo worsens in the dark should un- dergo caloric vestibular testing, as described above. A fistula test should be performed whenever a perilymph fistula is sus- pected, as well as routinely in chronic otitis. Digital pressure on the tragus suffices, in some cases, to provoke the symptoms; in other cases, a pressure wave of graded in- 698 9DiseasesAffecting the Cranial Nerves Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. Normal finding Head rotation Final position R L 1 1 2 3 1 2 3 2 3 Amplitude R L 1 2 3 Am p litude Saccade Time Head rotation Eye movement Eye movement Deficit of right horizontal semicircular canal a c b Fig. 9.30a–c Head thrust maneuver for testing of the horizontal semicircular ca- nal. (Explanation on p. 698 of text; adapted from Huber.) Disturbances of the Vestibulocochlear Nerve 699 Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. a b Fig. 9.31a, b Modified B´ar´any pointing test. a The patient points with her extended in- dex fingers to the ex- aminer’s index fin- gers. b The patient closes her eyes. Deviation to one side or the other indi- cates asymmetry of vestibular tone. tensity can be created in the external ear canal by stepwise inflation of a Politzer balloon.Apositivetestisas- sociated with the appearance of Hen- nebert’s sign (vertigo and nystagmus to the affected side). This test detects fistulae of the lateral semicircular ca- nal (912). 700 9DiseasesAffecting the Cranial Nerves Mumenthaler, Neurology © 2004 Thieme All rights reserved. Usage subject to terms and conditions of license. [...]... side Nystagmus may be present or absent These patients usually also suffer from complex partial and grand mal seizures, of which vertigo may be the aura Migraine and Vertigo (p 80 4) Vertigo may be the expression of migraine (so-called “vestibular migraine”) This condition is easy to di- Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license Disturbances... der topischen Gehirn- und Rückenmarksdiagnostik, Basle: Schwabe, 1953) Abbreviations: add = adductor, artic = articularis, dig = digitorum, f = fasciae, int = internus, obt = obturator (Cont.) 1 Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license 720 10 Spinal Radicular Syndromes Table 10.2 (Cont.) Mumenthaler, Neurology © 2004 Thieme All rights... denervation produces a dermatomal, usually band-like zone of hypesthesia, which, because of the overlap between neighboring dermatomes, is not always easy to demonstrate Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license 7 18 10 Spinal Radicular Syndromes General Symptoms and Signs > Dermatomal sensory deficit (cf der- Lesions of individual spinal nerve... the tongue occurs in the elderly as a form of glossodynia, without any known cause (p 82 6) The paroxysmal pain of trigeminal neuralgia may affect one-half of the tongue (which receives its sensory innervation from CN V) Paresthesiae and transient “falling asleep” of one-half of the tongue are found in the so-called neck-tongue syndrome (313a) Painful trophic disturbances of the tongue can be seen in isolation... well as of labyrinthine atelectasis or a central lesion Precise observation of the clinical manifestations generally Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license 7 08 9 Diseases Affecting the Cranial Nerves enables a clear-cut differentiation of BPPV from other causes of positional and positioning vertigo Neurovascular compression syndromes... Bilateral central tongue weakness, however, as in pseudobulbar palsy (p 384 ), causes severe dysarthria and dysphagia, and thus considerable functional impairment The tongue is not atrophic The buccolingual apraxia and oral diplegia of Foix-Chavany-Marie syndrome were mentioned in an earlier chapter (p 385 ) infection or cause (81 6) without identifiable Further causes Pain in the tongue may be due to... in 30–60 % after 10–20 years Nonetheless, the course is generally benign, in that 80 % of cases remit spontaneously in 5–10 years Diagnosis The diagnosis of Meniere’s disease is ´ ` based on the clinical triad described above The administration of hyperosmolar substances, such as glycerin Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license Disturbances... Impaired Proprioception Spinal cord lesions that involve the posterior columns (p 441) and polyneuropathies (p 581 ) may produce vertigo, or simply unsteadiness of stance and gait, as their principal symptom because of impaired proprioception These problems worsen Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license 710 S 9 Diseases Affecting the Cranial... an osteolytic process (such as chronic otitis with cholesteatoma) Particular entities to be borne in mind during history-taking include head trauma, barotrauma (flying, diving), Valsalva maneuvers (e.g., during coughing, blowing the nose, or weight-lifting), or surgical procedures on the stapes The fistula test is usually positive (p 6 98) Tullio’s phenomenon is also demonstrable in many cases: loud acoustic... present only when the labyrinth is stressed – i.e., only with certain head movements Mumenthaler, Neurology © 2004 Thieme All rights reserved Usage subject to terms and conditions of license Disturbances of the Vestibulocochlear Nerve Benign Paroxysmal Positioning Vertigo (BPPV) (Cupulolithiasis, Canalolithiasis) (237, 85 6) This disorder consists of transient, severe vertigo induced by changes in the . or lin- ear displacement implies a vestibu- lar deficit. Otoscopy and a complete neurologi- cal and general physicalexamina- tion complete the work-up. The ex- aminer should remember to mea- sure. diplopia). Accompanying vegetative distur- bances point to a peripheral vestibu- lar origin for vertigo, as such distur- bances are generally only mild in cen- tral vestibular or nonvestibular ver- tigo. Gait unsteadiness. maneuver (Hal- magyi-Curthoys test) (376a) is used to test the oculovestibular re- flex in the horizontal plane and is thus a test of the horizontal semi- circular canal. The examiner rap- idly turns