Perceptual disorders Flashcards
Achromatopsia
Loss of all cone receptors; no color vision, poor vision in lit conditions, poor sptial detail
Congenital analgesia
Lack of nociceptors; cannot feel pain, suceptible to infection, injury, and loss of limbs; cause of Leprosy
Cause of total blindness
Complete damage to V1
Opposite of blindsight
Anton-Babinski syndrome
Visual object agnosia
Inability to recognize objects; left occipital lobe (V2), although most common bilateral
Object agnosia for drawings
Location of damage
Cannot recognize drawings (2D objects) but can recognize objects in real world
V2
Prosopagnosia locations of damage (2)
Bilateral damage to interior temporal area, or:
Right posterior parietal lobe
Cortical motion blindness (akinetopsia)
Location of damage
Cannot detect motion
Small visual area (MT, V5)
Hemifield Neglect
Location of damage
Inability to recognize and neglect of one side of visual field or body
Right poterior parietal lobe
Dorsal simultanagnosia
Location of damage
Inability to see multiple things at same time
Bilateral damage to parietal and occipital lobes
Ventral simultanagnosia
Inability to recognize multiple things at same time (can see them)
Bilateral damage to temporal and occipital lobes
Paralexia vs paragraphia
Reading only one side of word vs writing only one side of word
Hemiakinesia
Poverty of movement of one side of body
Anosognosia
Location
Denial of illness or symptoms
Frontal and parietal lobes
Astereognosia (tactile aphasia)
Inability to recognize objects from touch
Asomatognosia
Location
Loss of knowledge or sense of one’s own body & bodily condition; may be unilaterlal or bilateral loss of sensation
Most common: neglect of left side of body resulting from right hemispheric lesions
Somatoparaphrenia and misoplegia
Location
Denial of ownership of affected limb or hand
Feelings of revulsion towards limb
Substantial right hemisphere lesions, involving parietal and somatosensory cortex
Agnosia
Conscious inability to identify sensory stimuli not due to deficits in sensory, verbal, or cognitive abilities
Phantom limb phenomenon
Sensation of amputed limb
Cortical neurons for that limb may continue to fire but can also occur for congenital limb loss
Apraxia
Skilled loss of movement that is not caused by weakness; an inability to move; abnormal tone or posture
Intellectual deterioration, poor comprehension, or other disorders of movement such as a tremor
Ideomotor apraxia
Patient unable to copy movements or make gestures
Left posterior parietal area
Constructional apraxia
Patients are unable to perform sequenced activities such as assembling, building, or drawing
Either parietal lobe
Auditory agnosias
Difficulty distinguishing between environmental sounds or environmental from speech sounds
Types of auditory agnosias
Semantic associative - loss of meaning of spoken words; lesion to left hemisphere (Wernicke’s area)
Discriminitive - cannot interpret non-speech sounds and relate their cause; right hemisphere damage
Phonagnosia
Inability to recognize or distinguish between voices
Recognition: right parietal
Discrimination: unilateral temporal
Amusia
Disruption in recognition of music
Anosmia
Inability to detect odors
Hyposmia
Decreased ability to detect odors
Dysosmia
Distorted identification of smell
Phantosmia
Perception of smell without odor present
Causes of anosmia (4)
Inflammation of nasal passages
Minor head trauma causing damage to frontal lobe or olfactory cortex
Congenital
Degenerative diseases (e.g., Parkinson’s, Alzheimer’s)
Ageusia
Inability to taste
Hypogeusia
Decreased ability to taste
Dysgeusia
Disordered taste sensation
Causes of ageusia (2)
Damage to lingual or glossopharyngeal nerve, or chorda tympani
Neurological conditions like Bell’s palsy and MS
Time agnosia
Loss of comprehension of the succession and duration of events
Damage to basal ganglia (causes slowing of mental processing), schizophrenia, or autism
Difference between time agnosia caused by autism and schizophrenia
Autism - agnosia for long time intervals
Schizophrenia - all time intervals
