Central vestibular syndromes in roll, pitch, and yaw planes: Topographic diagnosis of brainstem disorders
ABSTRACT Evidence is presented for a clinical classification of central vestibular syndromes according to the three major planes of action of the vestibulo-ocular reflex (VOR): yaw, pitch, and roll. The plane-specific vestibular syndromes are determined by ocular motor, postural, and perceptual signs. Roll plane signs are: torsional nystagmus, skew deviation, ocular torsion, tilts of head, body, and perceived vertical; pitch plane signs are: upbeat/downbeat nystagmus, forward/backward tilts and falls, deviations of perceived horizontal; yaw plane signs are: horizontal nystagmus, past pointing, rotational and lateral body falls, deviation of perceived straight-ahead. The thus defined VOR syndromes allow for a precise topographic diagnosis of brainstem lesions as to their level and side. A tone imbalance in roll indicates unilateral lesions (ipsiversive at pontomedullary level, contraversive at pontomesencephalic level). A tone imbalance in pitch indicates bilateral (paramedian) lesions or bilateral dysfunction of the flocculus. It is hypothesized that signal processing of the VOR in roll and pitch is conveyed by the same rather than separate ascending pathways in the medial longitudinal fasciculus and the brachium conjunctivum. A unilateral lesion (or stimulation) of these ‘graviceptive’ pathways (which transduce input from vertical semicircular canals and otoliths) affects function in roll, whereas bilateral lesions (or stimulation) affects function in pitch. Thus, the vestibular system is able to change its functional plane of action from roll to pitch by switching from a unilateral to a bilateral mode of operation. Therefore a common integrator system is efficient (and sufficient) for both eye movements in roll and pitch (rostral interstitial nucleus of the medial longitudinal fasciculus and rostral interstitial nucleus of Cajal). Clinically this means that bilateral syndromes in roll (skew torsion) manifest in a syndrome in pitch (upbeat- or downbeat nystagmus). Pure syndromes in yaw are rare, since the small causative area covering the medial and superior vestibular nucleus is not only adjacent to but overlapped by the structures also subserving roll and pitch function. A lesion frequently results in mixed (e.g., torsional and horizontal) nystagmus. The lesional sites of yaw syndromes are restricted to the pontomedullary level because of the short distance between the vestibular nuclei and the integration center for horizontal eye movements in the paramedian pontine reticular formation. Syndromes in roll and pitch, however, may arise from brainstem lesions located in an area extending from the medulla to the mesencephalon, an area corresponding to the large distance between the vestibular nuclei and the integration centers for vertical and torsional eye movements in the rostral midbrain.
Chapter: Paroxysmaler Schwindel01/2006: pages 88-108;
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ABSTRACT: Schwindel ist eines der hufigsten Leitsymptome in der Allgemeinmedizin und nach dem Kopfschmerz das hufigste Leitsymptom in der Neurologie. Die verschiedenen Schwindelsyndrome sollten nach organischen und somatoformen Syndromen unterschieden werden. Leider werden somatoforme Schwindelerkrankungen oft nicht oder versptet in die Differenzialdiagnose einbezogen, weshalb die Diagnose verzgert gestellt wird. Dies trgt zu der ohnehin schnellen Chronifizierung dieser Schwindelerkrankungen bei und fhrt hufig zu einer enormen Beeintrchtigung der Lebensqualitt bis hin zur Frhberentung der Patienten und zu hohen Krankenkassenkosten. Daher ist bei komplexen Schwindelerkrankungen eine frhe interdisziplinre Diagnostik, die somatische und psychosomatische Ursachen einschliet, hilfreich und erforderlich.Vertigo is one of the most common cardinal symptoms encountered in the practice of general medicine and after headache the most frequent major complaint in neurology. The various vertigo syndromes should be differentiated according to organic and somatoform manifestations. Unfortunately, somatoform vertigo disorders are often not included in the differential diagnosis or belatedly considered, which delays the diagnosis. This compounds the tendency of vertigo disorders to rapidly become chronic and frequently results in severe impairment of the patients quality of life, even precipitating early retirement and incurring high costs for healthcare systems. Hence, in cases of complex vertigo disorders, early interdisciplinary cooperation is both helpful and essential during diagnostic work-up to include signs of somatic and psychosomatic origin.Der Nervenarzt 01/2004; 75(3):281-302. · 0.86 Impact Factor
- Arquivos De Neuro-psiquiatria - ARQ NEURO-PSIQUIAT. 01/2005; 63(1).