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1 An Approach to the Patient with (Recent Onset) Spontaneous Episodic Vestibular Syndrome𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: A vascular etiology should always be on the differential diagnosis of the recent onset of the spontaneous (unprovoked) episodic vestibular syndrome (EVS), especially in the older population and when vascular risk factors ...Image
2 An Approach to the Patient with Acute Onset Prolonged Vertigo𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: A vascular etiology should always be on the differential diagnosis of the acute onset prolonged vertigo, especially in the older population and when vascular risk factors are present. However, young patients can suffer fr...Image
3 Ocular Motor & Vestibular Features of the MLF Syndrome (Figures 1, 2, and 3)This 61-year-old woman with HTN and DM presented for evaluation of acute onset diagonal diplopia. Adduction OS was about 60% of normal while medialization OS improved with convergence. In right gaze, dissociated abducting nystagmus was present OD, and there was a clear adduction lag when asking he...Image
4 Figure 61: Vascular Distribution and Anatomy (Including 6th, 7th, 8th Nerves, MLF) of the PonsIn this axial section of the pons, the proximity of the 7th (VII) and 8th (VIII) fascicles can be appreciated, and a lateral inferior pontine syndrome (anterior inferior cerebellar artery, AICA territory), which could involve both of these fascicles, could cause acute prolonged vertigo accompanied b...Image
5 Figure 27: Vascular Supply of the Optic Nerve Head, Choroid and RetinaThe ophthalmic artery is a branch of the internal carotid artery, which in turn, supplies the posterior ciliary (to choroid and outer retina) and central retinal (to inner retina) arteries. The central retinal artery (CRA) enters the optic nerve about 1 cm posterior to the globe, and an embolus may ...Image
6 Figure 43: How the Brain Makes Sense of What It Sees - The Dorsal and Ventral Visual Pathways, and a 3 Tiered Approach to Vision1) Ventral ("what") stream - this begins with the ‘P' retinal ganglion cells à parvocellular layers of the lateral geniculate nucleus (LGN, 3-6) à V1/striate cortex (in blue) à V4/V4a (fusiform and lingual gyri) à occipitotemporal regions. 2) Dorsal ("where") stream - this begins with the ‘M...Image
7 Figure 61: Vascular Distribution and Anatomy (Including 6th, 7th, 8th Nerves, MLF) of the Pons (Supplement)Image
8 Figure 61: Vascular Distribution and Anatomy (Including 6th, 7th, 8th Nerves, MLF) of the Pons (Supplement)Image
9 CANVAS (Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome) Video Head Impulse Test (vHIT) FigureCANVAS (Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome) is a genetic condition consisting of slowly progressive late-onset ataxia, bilateral vestibulopathy, sensory neuropathy, chronic cough, and autonomic dysfunction. While the term vestibular areflexia typically implies bilateral...Image
10 Vestibular Neuritis with + Head Impulse Test and Unidirectional Nystagmus (Figure 1)Vestibular neuritis is the most common cause of the acute vestibular syndrome, which is characterized by continuous vertigo and spontaneous nystagmus lasting days. It may be mimicked by central causes, including stroke, but in the hands of subspecialists, the HINTS+ (Head Impulse, Nystagmus, Test of...Image
11 A Comparison of Nystagmus and Saccadic Intrusions/OscillationsNystagmus can be classified into pendular and jerk waveforms, where both are generated by a slow, pathologic phase. Corrective phase (the position reset mechanism) differs. In pendular nystagmus, the eyes move back and forth with about the same velocity and amplitude, similar to that of a pendulum...Image
12 Neuro-Ophthalmic Features and Pseudo-MG Lid Signs in Miller Fisher Syndrome (Figure 1)This is a 51-year-old woman who presented with imbalance, acute onset dizziness and diplopia that developed over three days following two weeks of upper respiratory infection and bacterial conjunctivitis. When she was initially seen as an outpatient, nystagmus was noted to the right and left, and a ...Image
13 Medullary Structures Relevant to Upbeat NystagmusThis is an axial section of the medulla, slightly more caudal as compared to (please refer to figure "medullary structures relevant to the ocular motor and vestibular consequences of the lateral medullary (Wallenberg) syndrome). Again seen are the inferior cerebellar peduncle (ICP) and caudal aspect...Image
14 Sagittal Section of the Brainstem Showing Structures Related to Normal Eyelid FunctionSeen here is a sagittal view of the brainstem, with the structures relevant to normal eyelid function highlighted. The M-group, which can be found medial to the riMLF (coordinates eye and lid movements), has (weak) projections to the facial nucleus for frontalis muscle contraction, and (strong) proj...Image
15 Central Anatomy of the Fourth NerveThe IVth or trochlear nucleus is located ventral to the central periaqueductal grey matter, dorsal to the medial longitudinal fasciculus (MLF) and medial to the oculosympathetic tract at the level of the inferior colliculus. The fascicles of the IVth nerve travel dorsally and caudally around the cen...Image
16 Eyelid AnatomySeen here are the major muscles of eyelid opening and closure. The levator palpebrae, which is innervated by the oculomotor nerve, inserts on the tarsus via the levator aponeurosis and directly on the skin of the upper eyelid. The superior tarsal muscle (also known as Muller's muscle, which is inner...Image
17 Vertical Semicircular Canal PathwaysAnterior Canal Pathway Afferents that originate in the anterior canals (AC) of the peripheral labyrinth first synapse in the ipsilateral vestibular nucleus. Three pathways exist: 1) medial longitudinal fasciculus (MLF) - right AC afferents to right medial vestibular nucleus (MVN), decussate and asc...Image
18 Relationship Between Semicircular Canals and Extraocular MusclesFigure 1: When stimulated, each of the 6 angular acceleration detecting semicircular canals (3 on the right and 3 on the left) responds with a conjugate eye movement, with the vector(s) indicated below. PC=posterior canal; HC=horizontal (also known as lateral) canal; AC=anterior (also known as super...Image
19 Pons: 6th and 7th Nerve Anatomy and the Central Segmental TractFrom this cross-section of the pons, the proximity of the 6th nucleus to the 7th nerve fascicles is apparent. This is the basis of the so-called facial colliculus syndrome, where an ipsilesional horizontal gaze palsy from a nuclear 6th lesion (usually related to stroke or demyelination) can be seen ...Image
20 Coronal Section of the Brainstem Showing Ocular Motor Nuclei and Anatomy of the Vestibular Nucleus (with SCC Inputs)(A) Seen here is a coronal view of the brainstem showing the locations of the ocular motor nuclei (IIIrd, IVth, VIth) as well as the nuclei of VII and VIII (vestibular and cochlear). The vestibular nucleus (VN) is divided into the inferior, lateral, medial, and superior subnuclei, and the medial ves...Image
21 Saccadic Pathways in the Brainstem and Cerebellum & Mechanism for Saccadic Dysmetria in Wallenberg Syndrome - Normal Function of the Brainstem/Cerebellar Saccadic PathwaysThe inferior cerebellar peduncle (ICP) carries climbing fibers to the dorsal vermis, and these fibers have an inhibitory influence over the Purkinje cells. These Purkinje cells normally inhibit the ipsilateral fastigial nucleus, and the fastigial nucleus projects to the contralateral inhibitory burs...Image
22 Atypical PC BPPV Variant FiguresFigure 1: Atypical posterior canal BPPV variants The labyrinth consists of the cochlea (C), two otolithic organs including utricle (U) and saccule (S), and three semicircular canals including anterior canal (AC), horizontal canal (HC), and posterior canal (PC). A. If otoconia are located within the ...Image
23 Oculopalatal Tremor with Prominent Nystagmus, Bilateral Horizontal Gaze Palsy, and Bilateral Facial Palsies (Figure 1)Figure 1, MRI T2 sequence demonstrating hyperintensities involving bilateral inferior olives of the medulla. This is a 50-year-old woman who experienced the acute onset of right sixth and seventh nerve palsies and left hemiparesis. Two cavernomas within the right pons (one in the region of the facia...Image
24 Triangle of Guillain-MollaretSeen here is a schematic representation of the Gullain-Mollaret triangle (Figure 1), also referred to as the dentato-olivary pathway, reflecting the 3 points of this imaginary triangle - 1) dentate nucleus, 2) red nucleus, and 3) inferior olivary nucleus. The olive sends decussating climbing fibers ...Image
25 The Utriculo-Ocular Motor Pathways - Physiologic and Pathologic Ocular Tilt Reaction: Physiologic Ocular Tilt Reaction (OTR) (Figure 1)A skew deviation is a non-paralytic vertical ocular misalignment that is due to imbalance in the utriculo-ocular motor pathways. While vestibular jerk nystagmus is a consequence of static semicircular canal pathway imbalance (e.g., left-beating nystagmus due to acute right vestibular hypofunction fr...Image
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