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Dizziness
Published in Henry J. Woodford, Essential Geriatrics, 2022
Lesions affecting the central vestibular nuclei can cause vertigo, for example, lateral medullary syndrome (see page 208). There will be associated neurological signs dependent on the vascular territory involved, for example, dysarthria, diplopia, hemianopia and sensory/motor signs. Vertigo in isolation is unlikely to be due to a stroke. A study found that 10% of cerebellar strokes (confirmed by MRI findings) presented with vertigo in isolation.10
Cranial Neuropathies I, V, and VII–XII
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
The first-order sensory neurons of the vestibular pathway are bipolar cells located in Scarpa's ganglion (vestibular ganglion), in the fundus of the internal auditory meatus. The vestibular portion of the membranous labyrinth is divided into two sections: kinetic labyrinth (formed by the semicircular canals), and the static labyrinth (formed by the saccule and utricle). The vestibular bipolar neurons send peripheral projections to the hair cells in the semicircular canals, saccule, and utricle. Their central projections are to the four vestibular nuclei in the brainstem (lateral, medial, superior, and inferior) located in the caudal pons and rostral medulla. From the vestibular nuclei, central fibers are projected to the nuclei of the CNs responsible for extraocular movements (through the medial longitudinal fasciculus), the spinal cord (via the lateral and medial vestibulospinal tracts), and the flocculonodular lobe of the cerebellum.37
Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
There are four vestibular nuclei on each side, located in the rostral medulla and caudal pons (Figure 12.17): superior, lateral, medial, and inferior. The lateral vestibular nucleus is also known as Deiters’ nucleus. Cerebellar afferents to the vestibular nuclei project ipsilaterally from the vermis of the anterior lobe to the lateral vestibular nucleus, from the flocculonodular lobe to the other three vestibular nuclei, and bilaterally from the fastigial nucleus to the lateral and inferior vestibular nuclei. The vestibular nuclei integrate a broad range of visual and somatosensory inputs, including inputs from the spinal cord, particularly neck proprioceptive information, inputs from subcortical visual centers, and inputs from the cerebral cortex, including premotor head movement commands.
Assessing lesion location, visual midline perception and proprioception may assist outcome predictions for people affected by lateropulsion
Published in Disability and Rehabilitation, 2023
The central processing of vestibular inputs commences in the vestibular nucleus which is located in the medulla and pons. Ipsilateral inputs then ascend the brain stem bilaterally as they travel to the posterolateral and paramedial nuclei of the thalamus. The first location of multisensory integration is between the vestibular and visual systems in the superior collicuili of the midbrain, where the vestibulo-ocular reflex is mediated. Another location of multisensory integration is the posterolateral nucleus of the thalamus where both vestibular and proprioceptive inputs converge. From the thalamus, vestibular inputs travel to the non-dominant parieto-insular-vestibular cortex which testifies to lateralisation in the cortical processing of vestibular inputs [6]. Vestibular inputs also travel to the cerebellum, thus a large portion of cerebellar lesions can also manifest as lateropulsion [7].
Vestibular function in children with generalized epilepsy and treated with valproate
Published in Expert Review of Clinical Pharmacology, 2022
Sherifa Ahmed Hamed, Amira Mohamed Osiely
The vestibular system is divided into peripheral and central components. The peripheral component is composed of the semicircular canals, otolith (saccule and utricle) organs and the superior and inferior vestibular nerves. The central component begins from the point of entrance of vestibular nerves to the brainstem, the medial and lateral vestibular nuclei and the central inter-relations and connections to the thalamus and cerebral cortex. The semicircular canals sense horizontal angular head accelerations. Their afferents project to the medial vestibular nuclei via the vestibulo-ocular reflex (VOR). They provide reflexive ocular motor responses for maintenance of gaze stability. The otolith organs sense linear acceleration and static tilt in relation to gravity. Their afferents project to the lateral vestibular nucleus via the vestibulo-spinal reflex (VSR) for postural control and via connections to the cerebellar neurons, thalamus, and higher-cortical areas for balance, self-motion, and gravity direction [14].
Current perspectives on galvanic vestibular stimulation in the treatment of Parkinson’s disease
Published in Expert Review of Neurotherapeutics, 2021
Soojin Lee, Aiping Liu, Martin J. McKeown
Anatomically, the vestibular nerve combines with the cochlear nerve and becomes the vestibulocochlear nerve. Traveling by the cerebellopontine angle, this nerve enters the brainstem at the pontomedullary junction where the vestibular and cochlear nerves separate [49]. Some of the nerve fibers project to the flocculonodular lobe and nearby vermis of the cerebellum, while the majority of the fibers project to the ipsilateral vestibular complex in the pons [49]. The vestibular complex is where the vestibular inputs are primarily processed, and consists of four major nuclei including medial, lateral, superior, and inferior [50] as well as several adjacent cell groups. The vestibular pathways from the vestibular nuclei have different functional roles. Projections to the spinal cord are essential for postural reflexes to adjust head and body movements [51], and projections to the ocular motor nuclei are critical for compensatory eye movements during head motion (the vestibular-ocular reflex). Projections to the cerebellum are important for balance, postural control, and movement coordination [49], and pathways to the thalamus, hippocampus, and ultimately to the cortical areas are responsible for multisensory integration [50,52], contributing to movement planning and execution, spatial navigation and memory, attention, and emotional processing [52–54].