1/6. Dysphagia in a patient with lateral medullary syndrome: insight into the central control of swallowing.BACKGROUND & AIMS: Central control of swallowing is regulated by a central pattern generator (CPG) positioned dorsally in the solitary tract nucleus and neighboring medullary reticular formation. The CPG serially activates the cranial nerve motor neurons, including the nucleus ambiguus and vagal dorsal motor nucleus, which then innervate the muscles of deglutition. This case provides insight into the central control of swallowing. methods: A 65-year-old man with a right superior lateral medullary syndrome presented with a constellation of symptoms, including dysphagia. The swallow was characterized using videofluoroscopy and esophageal motility and the results were compared with magnetic resonance imaging (MRI) findings. RESULTS: Videofluoroscopy showed intact lingual propulsion and volitional movements of the larynx. Distal pharyngeal peristalsis was absent, and the bolus did not pass the upper esophageal sphincter. manometry showed proximal pharyngeal contraction and normal peristaltic activity in the lower esophagus (smooth muscle), but motor activity of the upper esophageal sphincter and proximal esophagus (striated muscle) was absent. MRI showed a lesion of the dorsal medulla. CONCLUSIONS: These findings are compatible with a specific lesion of the connections from a programming CPG in the solitary tract nucleus to nucleus ambiguus neurons, which supply the distal pharynx, upper esophageal sphincter, and proximal esophagus. There is functional preservation of the CPG control center in the solitary tract nucleus and of the vagal dorsal motor nucleus neurons innervating the smooth muscle esophagus.- - - - - - - - - - ranking = 1keywords = movement (Clic here for more details about this article) |
2/6. Benedikt and "plus-minus lid" syndromes arising from posterior cerebral artery branch occlusion.A 53-year-old man was admitted with diplopia, right ptosis, left lid retraction, mild left sided weakness and involuntary movements. Neurological examination revealed plus-minus lid and Benedikt's syndromes together. magnetic resonance imaging (MRI) showed two distinct mesencephalic infarctions in territories of paramedian and pedincular perforating arteries. magnetic resonance angiography (MRA) showed severe stenosis of proximal segment of the right posterior cerebral artery (PCA). Rare clinical presentations such as Benedikt and plus-minus syndromes can be seen together and be due to stenosis of the posterior cerebral artery with specific regional infarctions.- - - - - - - - - - ranking = 1keywords = movement (Clic here for more details about this article) |
3/6. Mapping of brainstem lesions by the combined use of tests of visually-induced eye movements.To determine the diagnostic value of visually-induced eye movements for indicating the lateralization of the lesion, optokinetic nystagmus (OKN), fixation-suppression of caloric nystagmus and pursuit eye movements were investigated in 28 patients who showed discrete unilateral brainstem lesions. In all patients, pursuit gains decreased in parallel with the direction of the impairment of slow-phase OKN velocity with a significant left/right difference. Decreases of gains were predominantly towards the affected side in 22 patients, whereas they were predominantly towards the contralateral side in 2 patients with dorsal tegmental pontine lesions and in 4 out of 8 patients with Wallenberg's syndrome. The relationship of pursuit gains to percentage reduction of fixation-suppression of caloric nystagmus (%FS) showed no correlation. The following four groups were classified. In group A, which was the largest, pursuit gains and %FS decreased predominantly towards the lesioned side. This group consisted of 5 patients with lesions in the midbrain, 6 patients with lesions in the ventral pons and 4 out of 8 patients with Wallenberg's syndrome. The opposite of group A was group D, showing reverse electro-oculographic (EOG) patterns to those in group A in relation to the lesioned side. Group D consisted of 2 patients with lesions in the dorsal pontine tegmentum. This observation, taken together with the decreases of pursuit and OKN gains in relation to the lesioned side, might indicate that lesions of ascending fibres are responsible for pursuit and OKN abnormalities. Group B, consisting of 7 patients with lesions either in the superior or middle cerebellar peduncles, showed decreased pursuit gains predominantly towards the lesioned side and %FS reduced predominantly towards the side contralateral to the lesion. EOGs of these patients were consistent with the results of floccular ablation in the monkey. In group C, these two parameters showed patterns opposite to those in group B in relation to the lesioned side and this group consisted of the other 4 patients with Wallenberg's syndrome. In patients of this group, the inferior cerebellar peduncle might be involved. The combined use of these tests is thus useful for lateralizing the lesion in the brainstem.- - - - - - - - - - ranking = 6keywords = movement (Clic here for more details about this article) |
4/6. A case of Wallenberg's syndrome: ocular motor abnormalities.eye movements were measured objectively in a patient with Wallenberg's syndrome during the course of his 2-year recovery period. The patient exhibited a change in fixational and reading eye movement patterns consistent with concurrent reduction in symptoms. The results demonstrate the importance of clinical eye movement recordings in such patients to understand more fully the relationship between the visually related symptoms and the objective oculomotor correlates.- - - - - - - - - - ranking = 3keywords = movement (Clic here for more details about this article) |
5/6. Task dependent variations of ocular lateropulsion in Wallenberg's syndrome.The eye movements of a patient with a left lateral medullary infarct (Wallenberg's syndrome) were recorded using the scleral search coil in magnetic field technique. When asked to look at spontaneously appearing targets, saccades to the left were generally accurate but those to the right reached the target by multiple step refixation saccades. Large amplitude rightward saccades were possible between two continuously visible targets or when making voluntary saccades in the dark. Vertical saccades, up or down, between spontaneously appearing targets were always associated with a leftward eye movement (lateropulsion). Voluntary vertical saccades between continuously visible targets showed that upward movements had left lateropulsion but downward movements were normal. Vertical voluntary saccades in the dark were oblique, upward saccades showing left lateropulsion and downward saccades rightward deviation. The aberrant horizontal components of normal oblique saccades. Possibly impaired assessment of verticality with incorrect eye position information produced by the infarct accounts for the lateropulsion in saccades in Wallenberg's syndrome.- - - - - - - - - - ranking = 4keywords = movement (Clic here for more details about this article) |
6/6. Visually guided eye movements in patients with Wallenberg's syndrome.To determine the lesions and the lateralization in patients with Wallenberg's syndrome, visually-guided eye movements were quantitatively analysed and these findings were compared with a lesioned site as revealed by magnetic resonance imaging (MRI). The 8 patients could be clearly classified into two subgroups based on the functional test of eye movements. In 4 patients, optokinetic nystagmus (OKN), pursuit eye movements and fixation-suppression of caloric nystagmus (FS), utilizing the slow phase velocity as a parameter, were impaired toward the lesioned side in the medulla. In the remaining 4 patients, OKN and pursuit eye movements were impaired toward the side contralateral to the lesion, whereas FS toward the lesioned side, indicating a lesion affecting not only the medulla but also the inferior peduncle and/or the cerebellum. Therefore, the functional visually-guided eye movements can provide a useful test battery with which to detect the lesion site in Wallenberg's syndrome.- - - - - - - - - - ranking = 9keywords = movement (Clic here for more details about this article) |