Phys Rehab: Visual Processing

Hemianopsia Definition

A visual field deficit that encompasses the inability to see in one or both visual fields. There are many types.

Visual Field Cut Behaviors

Abbreviated but organized scanning pattern including re-scanning and appropriate time and effort expended.

Allesthesia

Attributes sensory stimuli to opposite side; may also move the opposite limb requested

3 Theoretical approaches to visual processing

Deficit-specific approach Modified Information-processing theory May Warren's visioprocessing (VP) hieracrchy

Extinction (Unilateral Neglect)

Failure to report a stimulus on the involved side when bilateral stimuli are presented

Visual scanning is a combo of

Fixation Saccades Pursuits

Two types of visual processing

Focal (attentive) Ambient (pre-attentive) This is a feed forward system

5 Types of Unilateral Neglect

Hemi-inattention Hemispatial Visual Neglect Extinction Allesthesia Hemiakinesia

Hemi-Inattatention

Inability to orient or respond to stimuli on one side of the environment

Hemi-spatial Visual Neglect

Inability to orient to relevant contralateral visual stimuli

Hemiakinesia

Motor neglect

Consequences of visual field deficits

No driving Falls Injuries

Oculomotor Control Includes (7 items)

Ocular alignment Pupillary response ROM Fixation Accommodation Convergence Saccades

The Warren Visuoperceptual Hierarchy

Oculomotor Control; Visual Fields; Visual Acuity---> Attention---> Scanning---> Pattern Recognition---> Visual memory---> Visuocogniton---> Adaptation through vision

Visual neglect behaviors

Random and disorganized scanning with inefficient effort and no re-scanning.

2 Types of Visual Attention

Reflexive Voluntary

Unilateral Neglect Types

Sensory (spatial, proprioceptive, auditory, tactile, visual, mental images) Motor

Visual Fields Defined in degrees

Superior=60 Inferior=75 Nasal=60 Temporal=100

Visual Acuity

Visual accuracy near, far, and in contrast.