Definitions
Visual-perceptual
Form or pattern discrimination; color, shape, features of object regardless of location
Visual-spatial
Processing of visual orientation or location in space; depth, motion
- “Types” of visual-spatial processes
- Object localization- ability of any sensory system to locate object in space
- Line orientation- human cortex has detectors of line orientation; damage to right posterior disrupts this function, regardless of sensory modality
- Spatial synthesis- perceived spatial features of an object that make it “that object”
- Spatial attention- ability to pay attention to either right or left hemispace; contralateral parietal lobe
- Spatial mental operations- mental rotation (imagining an object if displace along a line); mental reflection (imagining an object reflected in a mirror)
Constructional ability (constructional praxis)
Ability to draw or assemble an object from component parts
- Integrative aspect- people with deficits may be able to reproduce components of design but not integrated whole
- on command or copying
Memory
- Spatial memory- short term; long term; discrete lesion (right hippocampus; thalamic mesiodorsal nucleus) can cause memory deficits with preservation of spatial perception
- Topographical memory- find way around; relies on landmark recognition, spatial attention, spatial memory
Development of Skills
Visual-spatial skills
Development of locomotion essential to development of visual-spatial skills
- Once child walks or crawls, changes way view space and increases strategies to solve spatial problems
- When infant allowed to move independently rather than being carried by others, has better grasp of spatial features
- Research shows strong correlation between self-produced movement and visual tracking
Verbal Representation of Visual-Spatial Concepts
Consistent developmental picture across languages in comprehension and elicitation
- In, on , under, next to
- Between, in back of, in front of (using a featured object¬)
- In back of, in front of (using a nonfeatured object)
Construction of 3-D Objects
- “Small scale models”- using everyday objects to represent other things (ex- pretend chair is a stove; long, flat block could be road or house depending on orientation)
- Uni-dimensional representation- forms are linear; house may be stack of blocks, but each block stands for a feature
- Two-dimensional representation- starts creating overall shape with blocks; begin to overlook boundaries of blocks and depict surface of object; uneven block on top for chimney
- Three-dimensional representation- building on all three axes; positions blocks so many facets join other blocks; builds interior vacant space
Drawing
- Interest in crayons; making marks
- Point-plot representations- spatial plotting of features of an object; features not contoured or connected
- Beginning figure-ground relationship- more visual-spatial likeness of object (long strokes for hair)
- Three dimensional space- scenes with figures side by side
Neuroanatomy
Right Hemisphere
- More white matter; less gray matter
- More associative cortex
- More interconnections
- Advantage for processing complex information; many modes within an single task
- Configurational processing; material that cannot be described adequately as a string of symbols (faces, 3D objects)
- Preference for global aspects
- Involvement in language- integration of relationships in verbal/written discourse; integrating verbal output; making verbal expression appropriate for context/emotion; humor; alternative meanings; intonation; prosody
Anterior Parietal Lobe
- somatosensory cortex
- involved with somatic sensation and perception
Posterior Parietal Lobe
- inferior posterior lobule- high order somatosensory and visual cortical fields
- superior posterior lobule- somatosensory association cortex
- integrating discrete elements into whole
- spatial, constructional, topographical skills
Where vs. What Streams
- Dorsal Visual Stream- “where”; info regarding spatial analysis and orientation; runs along top side of cerebrum from occipital to parietal visual areas
- Ventral Visual Stream- “what”; info regarding shape, pattern; runs along underside of cerebrum from occipital to temporal visual areas
Temporal Lobe
Nonverbal analogues of left hemisphere
- nonverbal sound discrimination, recognition, comprehension
- visual, auditory, tactile memory (faces, designs, melodies)
- anterior- storage; posterior- retrieval
Tests
Visual attention
- Cancellations tasks
- Line bisection
- Picture description- ask describe what in picture or count certain object in picture
- Reading- omit part of line
- Written expression- copy sentences
Visual recognition
- JLO
- Recognize objects under distorted conditions
- Facial recognition
- Discriminate rotations of objects
- Visual organization; incomplete figures
- Fragmented visual stimuli (Hooper)
- Ambiguous stimuli
Constructional skills
- Drawing tasks (VMI, Rey; copy vs free draw)
- Building tasks
Memory
- Visual recognition
- Visual reproduction
- Visual learning
Disorders
Visual Agnosia
- Inability to recognize object
- Associative- person can still draw or describe major details of stimuli
- Apperceptive- person cannot draw or match visual stimuli
- Agnosia vs anomia- if person can still describe what object is and what used for (only a naming deficit) then it is anomia
Prosopagnosia
- Inability to recognize previously known faces and learn new ones
- Applied to any visually ambiguous stimuli (ex. farmer not being able to recognize cows)
- Can perform generic recognition (say that a car is a car) but no specific membership (can’t say which manufacturer of car)
- Intact emotional recognition
Facial Processing
- Inability to recognize facial emotion- bilateral amygdala damage
- Deficit in social judgment of faces (judge as approachable and trustworthy)- amygdala
Simultanagnosia
- Inability to comprehend overall meaning of stimulus- can identify and describe isolated elements
- Can see parts, but not the whole
- Example- person looking at eyeglasses, says there’s a circle, another circle, stick and cross bar, concludes it must be a bicycle
- Difficulty understanding meaning of complex thematic pictures or seeing card combinations of a “hand” although know relative value of cards
Pure Alexia
- Word blindness- impaired ability to read single words or sentences
- Can copy them, normal visual acuity, normal recognition of nonverbal stimuli
- Lesion that disconnects language-related temporo-parietal cortex from visual association area
Disorders of Location and Orientation
- Deficits-inability to locate a building, find one’s room, describe either verbally or by map how to get someplace
- Can be caused by neglect or impairment of visuospatial memory- can no longer conjure up previously stored memories to get bearings and establish route
- Bilateral posterior lesions
Unilateral Spatial Neglect
- Tendency to neglect one-half of extrapersonal space- integrated disorder of attention and vision
- Tests involve having person draw a symmetrical picture (clock, flower).
- Neglect occurs contralateral to the brain lesion.
- Most often in acute phase of recovery.
- Seen with more frequency and severity after right hemisphere than left hemisphere lesions.
- Also seen following lesions of cortical and subcortical parietal lobe, dorsolateral frontal lobe, cingulated gyrus, thalamus, and reticular formation.
Balint’s Syndrome
- Disorder of spatial analysis
- “Acquired disturbance of ability to perceive the visual field as a while, resulting in unpredictable perception and recognition of only parts (simultanagnosia) which is accompanied by impairment of target pointing under visual guidance (optic ataxia) and inability to shift gaze at will toward new visual stimuli (ocular apraxia)”
- Three major components-
- Visual disorientation (simultanagnosia)
- Optic ataxia (deficit of visually guided reaching)
- Ocular apraxia (deficit of visual scanning)
- Visual disorientation is core. Person only able to grasp fraction of visual field, and this fragment is not stable and moves erratically. As a result, objects disappear from view, so can’t describe more than one or two parts of an object. Also fail to orient to new stimuli unless happens to be in window of vision
- Optic ataxia- person can point to parts of body, garments, sound, but not to visual stimuli
- Ocular apraxia- cannot direct gaze voluntarily toward new stimulus. Normally, person produces a quick saccade toward something new. Can’t do this, even if told something is there.
- Bilateral damage to occipitotemporal region
Constructional Apraxia
- “apraxia of the psychologist”- seen more in evals than in real life
- inability to assemble, join, or articulate parts in a unitary structure.
- parietal dysfunction, usually right
- Drawing- left hemisphere damage leads to drawing that is spatially correct, but oversimplified with omission of details
- Drawing- right hemisphere damage leads to fragmented drawing; may have details but lost whole of picture and spatial relations; may neglect left side
- Block constructions- left hemisphere damage see maintenance of 2×2 or 2×3 configuration but error with internal details; tend to recognize when incorrect
- Block construction- right hemisphere damage break configuration, but see internal details; do not appreciate when incorrect; may skew to right space
Disorders Demonstrating Deficits in Nonverbal Abilities
- Syndromes
- Velocardiofacial syndrome
- Williams syndrome
- deLange syndrome
- Sotos syndrome
- Turner syndrome
- Anomalies of brain or CNS
- hydrocephalus
- spina bifida
- congenital hypothyroidism (insufficient production of thyroid hormones; this hormone facilitates glial cell production)
- MS
- Metachromatic leukodystrophy
Hydrocephalus
- Increase in CSF volume in ventricular system
- Can result from structural abnormality blocking CSF outflow (Arnold Chiari)
- Children with IVH can develop as a result of blockage of CSF reabsorption
- Also associated with TBI, infectious diseases, tumor
- Classified three ways
- Complicated (associated with other clinical problems) or noncomplicated
- Communicating (obstruction occurs in subarachnoid spaces, where CSF is blocked as it leaved fourth vent) or noncommunicating (obstruction within vent system)
- Congenital or postnatal
- Consequences on brain development
- Stretch or destroy CC
- Affects white matter tracts, especially projection fibers near midline
- Disrupt myelination, resulting in reduced cortical mantel, reduced brain mass, and thinning of posterior brain regions.
- Multiple surgeries to correct shunt
- Neuropsych
- PIQ < VIQ
- visual-spatial/ visual-motor < language
- some studies kids with shunts did worse
- some language probs: rapid retrieval of info; automaticity; language discourse; cocktail party speech
- deficits in both verbal and visual memory
- executive deficits
- Studies show relationship between size of corpus callosum and nonverbal skills
ALL
- cancer of blood-forming cells in bone marrow; peak incidence 3-5 yrs of age
- strikes when CNS highly vulnerable to insult
- treatment goal is total eradication of disease; 95% chance of remission; > 50% chance of remission for 5 years.
- treatments are bad for CNS: radiation, intrathecal chemo, steroids
- cortical atrophy; lead to ventricular or subarachnoid space dilation
- leukoencephalopathy: myelin degeneration; white matter of both hemispheres; watershed areas
- mineralizing microangiopathy :degeneration of microvasculature; dystrophic calcifications of adjacent areas; CNS calcifications of gray matter, primarily around BG
- Neuropsych deficits are late effects
- 10 pt IQ drop
- nonverbal < verbal; arithmetic < reading
- nonverbal memory < verbal memory
- attention problems; difficulty focusing and planning responses
- executive deficits
- diminished response time and motor speed
- Risk factors associated with treatment effects
- Age: myelin still developing; < 5 is bad
- Gender: impairment more prevalent and severe in females; females more vulnerable to radiation/methotrexate combo (males may be more vulnerable to steroids)
- Treatment: combo of radiation and intrathecal methotrexate worse than just XRT. XRT dose > 2000 cGy and higher MTX associated with leukoencephalopathy
- Sequence of treatment: lower CNS pathology when IT MTX given before XRT rather than after. Hypothesized that radiation affects integrity of BBB, allowing increased penetration of MTX and reduced clearance of MTX from brain.
TBI
- Primary injury: coup/contrecoup; contusions and hemorrhages
- Secondary injury: edema, hematoma, seizure; major causes of tissue loss
- Late effects: white matter degeneration; cerebral atrophy; ventricular enlargement
- White matter degeneration primary pathological change in brain. As edema resolves, reduction in myelin, resulting in reduced bulk of cerebral white matter. Damage greatest in CC, parasaggital areas, internal capsules, and pons.
- Neurospych
- Decline in IQ
- PIQ more affected because of task demands, which require fluid problem solving and rapid motor output vs previously acquired info, which remains relatively intact
- after acute stage, language skills relatively intact; can see subtle problem with naming and fluency and discourse
- deficits in both verbal and visual memory
- deficits in attention and executive skills
Nonverbal LD
- Rourke- Final Common Pathway of White Matter
- Syndrome or cluster of features related to dysfunction of white matter; processing multi-modal novel info and spatial info
- Three areas of deficits
- neuropsychological
- academic
- social-emotional
- Where does it fit in as a syndrome?
- What criteria are used to diagnose?
- Overlap with NLD and Asperger’s- differential diagnosis
- NLD- neuropsych exam important
- AD- more of a behavioral diagnosis; looking for more social-emotional problems, behavioral rigidity, restricted interests
- Overlap with ADHD- social problems related to impulsivity