1. Sensory Pathophysiology Neurology Course 4th Year

2. 2 Function of sensory systems Monitor the internal and external environment Transmit peripheral signals to CNS for processing Critical for homeostasis: CNS needs information to make adjustments There are 4 steps associated with sensation: 1) Stimulus 2) Transduction 3) Electrical signals (APs) 4) Perception

3. Near-sighted patients (myopic) Hypermetropic patients Astigmatism Presbyopia Cataract 3 Refractive Disorders

4. Visual field defects are caused by interruptions of the visual pathways. Hemianopsia Homonymous hemianopsia quadrant-anopsia. Heteronymous hemianopsia Bitemporal hemianopsia Binasal hemianopsia. Localised blindness or scotoma 4 Visual field defects

5. Protanopia – lack of red colour detection Deuteranopia – green Tritanopia - blue 5 Colour blindness

6. Nerve deafness Presbyacusis Conduction deafnes A cortical hearing disorder Tinnitus (tinnitus aurium, literally ringing of the ears; tinnire = to ring) 1. Tonal (Subjective) tinnitus: 2. Non-tonal (Objective) tinnitus- may be heard by the examiner. s 6 Hearing loss - Deafness (hypacusis)

7. Vertigo (dizziness) Falling Nystagmus 7 Vestibular pathophysiology

8. Hemisection of the spinal cord - Brown-Séquard syndrome corticospinal tract combined with other descending motor pathways anterior horn descending autonomic fibers Interruption of an ascending pathway Syringomyelia Plexopathy Radiculopathy 8 Somatosensory pathways and their pathophysiology