Case 6 - Spatial Neglect Flashcards
Spatial Neglect Classic Definitions:
Heilman & Valenstein (1979): Inability to spontaneously report, respond, or orient towards events on the contralesional side of space with either limb or eye movements.
Mesulam (1985; 2000): Described as if that half of the world had abruptly ceased to exist in any meaningful form.
Clinical Presentation:
Halligan & Robertson (1999): Reduced awareness of contralesional space, usually following stroke. In severe cases, it can extend to ipsilesional space.
Esposito et al. (2021): Incidence of neglect after stroke: 38% in RH damage, 18% in LH damage.
Impact of Spatial Neglect:
Jehkonen et al. (2006); Hammerbeck et al. (2019): SN predicts poor functional recovery in RH stroke; longer hospital stays.
Chen et al. (2017): Significant pressure on caregivers of stroke survivors with spatial neglect.
Symptoms and Clinical Value:
Rich et al. (in prep.): Terms used to describe spatial neglect include visuospatial neglect, unilateral (spatial) neglect, hemineglect, inattention, hemi-inattention.
Spaccavento et al. (2017): Spatial Reference Frames (SRFs): Personal, Peri-personal, Extra-personal.
Clinical Value of SRFs:
Iosa et al. (2016); Moore et al. (2021): Different SRFs may have different associated outcomes and recovery processes.
Spatial Neglect Subtypes:
Demeyere et al. (2019): Egocentric neglect (relative to bodily midline) vs. Allocentric neglect (relative to midline of objects).
Spatial Neglect Modalities:
Rode et al. (2017): Different modalities include visual, auditory, motor, somatosensory, and representational neglect.
Visual Neglect and Co-morbidities:
Schofield & Leff (2009): Differentiating neglect and hemianopia; both can coexist.
Auditory Neglect:
Bellmann et al. (2001): Proposed subtypes based on lesion location (basal ganglia vs. frontotemporoparietal).
Motor and Representational Neglect:
Guariglia et al. (2005): Motor neglect involves reduced/absent movement on one side; Representational neglect involves reduced awareness of one side of mental imagery.
Catherine Bergego Scale: Quantifies anosognosia, the inability to recognize spatial neglect.
Causes of Spatial Neglect:
Li & Malhotra (2015); Karnath et al. (2001, 2004): Commonly caused by stroke in middle cerebral artery territory, often in right inferior parietal lobe/TPJ.
Working Theories of Spatial Neglect:
Representational Approach
Directional Hypokinesia
Activating-Orientating Hypothesis
Attentional Approach
Representational approach
Neglect is not a sensory disorder but a failure to exploit the left side of representational space.
Directional hypokinesia
Unilateral lesion hypoarouses the hemisphere causing selective loss of orientating response in hemispace contralateral to the lesion.
Activating-Orientating Hypothesis
Proposes that the allocation of attention is directed contralaterally to the activated hemisphere.
Attentional approach
Changing location of attention involves disengagement, movement, and re-engagement at the new location.
Neglect Characteristics:
Benefit from valid cues, but exhibit a higher cost when invalid cues are on the right, struggling to re-engage attention leftward. Neglect is identified as a problem in reallocating attention once directed to the right.
Cognitive Assessments:
Measure neglect-influenced cognitive abilities (attention, spatial navigation, language) using batteries (e.g., BIT, OCS) or standalone tests (e.g., cancellation, bisection, drawing).
Behavioural Inattention Test (BIT):
BIT-B: Behavioral, ADLs.
BIT-C: Conventional, cognitive subtests.
Subtests include star cancellation, line crossing, letter cancellation, line bisection, figure copying, and more.
Functional Assessments:
Observe daily activities impacted by neglect (e.g., meal preparation, grooming) using structured (CBS/KF-NAP, DENA) or unstructured methods.
Catherine Bergego Scale (CBS) and KF-NAP:
Clinician-rated and patient-rated scale for ADLs, also indicating anosognosia.
Checketts et al. (2020) Study:
Surveyed stroke clinicians, revealing a translational gap between research and clinical practice.
Importance of Treating Neglect:
Neglect predicts poor functional recovery; longer hospital stays; caregivers’ significant pressure.
Top-Down Approaches:
Focus on hierarchical cognitive network organization, teaching compensatory strategies, and cognitive control by the patient.
Visual Scanning Training: Trains systematic searching towards the neglected side, but effectiveness limited to trained tasks.
Sustained Attention Training (SAT): Trains sustained attention to facilitate spatial awareness, with modest improvements reported.
Other Top-Down Approaches: Tonic and phasic alertness training (TAPAT), practicing scanning/searching, and saccadic or eye movement training.
Bottom-Up Approaches:
Focus on afferent pathways to stimulate defective processes not under conscious control.
Caloric Vestibular Stimulation: Short-term effects, not well-established, uncomfortable side effects.
Prism Adaptation Training (PAT): Alters visual perception and recalibrates attention, showing promising results in improving neglect.
Other Bottom-Up Approaches:
Limb activation training, neck vibration, trunk rotation, haptic feedback, and non-specific interventions like noninvasive brain stimulation, occupational therapy, and pharmacological treatments.
