3) Homonymous Hemianopia & Hemi-neglect

1. ______ - disorders that can interrupt the visual pathways. Either direct injury or impingement on optic pathways results from: o Trauma o Tumors (often pituitary adenomas) 2. _____ - Any insufficiency of blood flow in the arteries that supply the retina or visual pathways can seriously affect vision. o 3. Anterior/middle/posterior cerebral arteries supply the optic nerve, optic chiasm, and optic tracts. o 4. Anterior/middle/posterior cerebral artery supplies the optic radiation and the visual cortex. o 5. The __________ arteries supply the brainstem and posterior cerebral artery. 6. _______ - Blindness in one eye o Note lesion 1 in the right optic nerve: o The right nerve tract will not work. o Results in 7. ___lateral blindness. o Therefore, full vision in the left eye and complete blindness in the right eye. 8. _____ - loss of half of the visual field for one or both eyes o Note lesion 2 at the optic chiasm o If it only involves fibers that originate in the nasal half of each retina, there will be loss of peripheral vision. If the entire optic chiasm is affected, there will be complete blindness. 9. _______ - loss of the corresponding visual half-fields in each eye o Interrupts fibers and vision originating on the same side of both eyes (homonymous) with loss of vision from half of each field (hemianopia) o Stroke on the right side: loss of the left visual field (aka you do not see things on the left) o Left-sided lesions: loss of the right visual field (aka you do not see things on the right) Homonymous Hemianopia leads to 10. ______ 10. _______ - inability of a person to process and perceive stimuli on one side of the body or environment, where that inability is not due to a lack of sensation o Due to this visual defect, clients are unable to see o People who approach them on their blind side (approach with care or you may frighten them). o Food on one side of their tray (they will not eat it because they cannot see it). o Half of their body (they will not wash it because they cannot see it). p This is like having 4 circuits plugged in, having a stroke, and 2 of the circuits become unplugged (nonfunctional). o In addition, if the stroke is on the right side of the brain, they may have impaired spacial orientation and impaired position sense (since the right side of the brain is responsible for this).

1. Disorders of optic pathways 2. Vascular lesions 3. Anterior and middle 4. Posterior 5. vertebral and basilar 6. Anopia 7. uni 8. Hemianopia 9. Homonymous Hemianopia 10. hemi-neglect

1. Paris as seen with bitemporal hemianopsia 2. Paris as seen with binasal hemianopsia 3. Paris as seen with left homonymous hemianopsia (stroke on the right). 4. Paris as seen with right homonymous hemianopsia (stroke on the left) 5. Dysarthria is a speech disorder that: A. Includes imperfect articulation of speech sounds and changes in the pitch or quality of voice. B. Relates to content of speech. C. Results in the inability to comprehend, integrate, and express language

1. No central vision in both eyes 2. No peripheral vision in both eyes 3. No peripheral vision in left, no central vision in right 4. No central vision in left, no peripheral vision in right. 5. B

The 2 optic 1. _____ meet and fuse in the 2. _____. Beyond the 2. _____ , they continue as optic 3. ______. The optic 4. ______ retain the information transmitted through the optic 3. _____ so that it can be carried to the brain. Full vision occurs when all of pathways from the retina and the optic nerve send messages to the 5. _____ cortex and other visual regions of the brain and brainstem. o Fibers of the optic tracts synapse in the 6. _____ of the 7. ______. The retina is divided into: 8. ____ & _____ half half In the optic chiasm, axons from the 9. _____ retina of each eye cross to the contralateral side and join with axons of the 10. _____ retina of the opposite eye to form the optic tracts. o Therefore, one optic tract has fibers from both eyes that transmit information to a single visual field: right or left. In addition to binocular vision, there is monocular vision (one eye): 11. The left peripheral field is seen exclusively by the right/left nasal/temporal retina. 12. The right peripheral field is seen exclusively by the right/left nasal/temportal retina.

1. nerves 2. optic chiasm 3. tracts 4. radiations 5. visual 6. LGN 7. thalamus 8. nasal & temporal half. 9. nasal 10. temporal 11. Left nasal 12. right nasal

Visual fields o Each eye sees part of a visual space. That visual space determines the visual field of the eye, defined as the area that is visible in 1. ____direction. o The simple lens system of each eye 2. _____ the image onto the 3._____. o The right and left sides of the visual field are 4. ______ after they cross at the 5. ______ o The visual field is divided into two hemifields that overlap to create a 6. _______ visual field. o In 6. ________ vision, both eyes work together in a coordinated manner so that sight from two eyes is blended and interpreted as one image o 6. _______ vision works well when there is normal alignment of the two eyes. It requires both 7. _____ fusion and 8. _____ fusion. o 7. _______ fusion: the association of the retina and the sensory cortex that promotes the fusion of 2 slightly dissimilar images. o 8. _______ fusion: precise coordination of the 2 eyes for gazing in all directions. The binocular field is divided into central and peripheral portions. Central portions of the retina provide high visual acuity. Peripheral portions of the retina provide the ability to detect moving objects.

1. one 2. Inverts, 3. retina 4. Reversed, 5. Optic chiasm 6. binocular 7. sensory, 8. motor