Beliefs in Right Hemisphere Syndromes: From Denial to Distortion

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurology

Background:

• Disorders of awareness, particularly those linked to right hemispheric dysfunction, often manifest as striking belief distortions.
• These distortions range from unawareness of paralysis (anosognosia for hemiplegia) to denial of paralysis, where beliefs starkly conflict with reality.
• Patient beliefs often serve as attempts to rationalize limitations or integrate incongruous information, drawing from past experiences and resisting modification.

Purpose of the Study:

• To address various proposed explanations for unawareness and puzzling beliefs in anosognosia for hemiparesis.
• To utilize anosognosia as a model for exploring belief distortions in other right-hemisphere associated clinical syndromes.
• To investigate the nature of startling belief distortions in neurobehavioral disturbances beyond anosognosia.

Main Methods:

• Review and synthesis of existing literature on anosognosia and related awareness disorders.
• Analysis of proposed theoretical frameworks, including sensory, cognitive, feedback, disconnection, and hemispheric asymmetry hypotheses.
• Exploration of belief formation and modification processes in the context of self-representation and external world perception.

Main Results:

• Multiple theories attempt to explain unawareness in anosognosia, including sensory, cognitive, and hemispheric asymmetry hypotheses.
• Belief distortions are also prominent in other right-hemisphere disorders, such as somatic illusions and misidentification syndromes.
• Difficulty in updating beliefs is a proposed mechanism underlying unawareness in these conditions.

Conclusions:

• Belief distortions associated with right hemispheric dysfunction represent a significant challenge in understanding awareness disorders.
• Anosognosia serves as a valuable model for studying these phenomena, highlighting altered representations of self and reality.
• Further exploration of these astonishing nonveridical beliefs is crucial for advancing our understanding of the self and the external world.