Visuospatial hemi-inattention following cerebellar/brain stem bleeding

Area of Science:

• Neuroscience
• Neurology
• Cerebellar research

Background:

• Neglect is a neurological disorder characterized by a lack of awareness or responsiveness to stimuli on one side of space.
• It most commonly results from right-hemisphere damage, affecting areas like the parietal lobe, frontal cortex, basal ganglia, and thalamus.
• Cerebellar lesions have also been increasingly associated with neglect symptoms.

Observation:

• This study reports on a patient with a right-sided posterior inferior cerebellar artery bleed.
• The patient exhibited left-sided visual hemi-inattention, despite having no visual field defects.
• Specific deficits included difficulties with visual extinction, complex motion detection, and attention shifts.

Findings:

• The patient demonstrated impaired detection of left-sided visual stimuli and slowed reactions to left-sided targets during covert attention shifts.
• Reading impairment was noted, specifically in locating the beginning of the next line of text.
• Despite significant deficits, the patient retained awareness of her condition and had normal visuoconstructive abilities.

Implications:

• This case suggests a potential link between cerebellar lesions and neglect, specifically visual hemi-inattention.
• The findings propose that damage to the right brain stem, secondary to cerebellar hemorrhage, may disrupt the noradrenergic ascending activation system.
• This disruption could transiently explain the observed hemi-inattention, offering new insights into the neuroanatomical basis of neglect.