How to differentiate hemianesthesia from left tactile neglect: A
preliminary case report
Issue title: Primary Progressive Aphasia and Post-Stroke
Aphasia: Some Complementary Insights into Brain-Behavior
Relationships/Hemispatial Neglect and Related Disorders
Affiliations: Laboratory of Neuropsychology, IRCCS San Camillo
Hospital, Venezia-Lido, Italy | Department of Neuroscience, University of Sheffield,
and Sheffield Teaching Hospital Foundation NHS Trust, Sheffield, UK | Department of General Psychology, University of
Padova, Padova, Italy
Note: [] Corresponding author: Konstantinos Priftis, Department of
General Psychology, University of Padova, Italy. E-mail:
Konstantinos.priftis@unipd.it
Abstract: When assessing for the presence of hemianesthesia, the examiner
touches the body of the patients, and requests that they report verbally the
location of the delivered tactile stimulus. Contralesional omissions of single
tactile stimuli, however, might be due to either primary somatosensory deficits
or to spatial attention impairment (i.e., neglect). In this preliminary study,
we tested whether clinical assessment can be improved to differentiate between
these two types of deficit by modifying the assessment procedure. K.L., a
patient with left unilateral neglect, was asked to detect tactile stimuli
delivered in two conditions: spatial attention distributed either to his left
or to his right hand, and spatial attention focused only on his left hand. Note
that K.L. did not receive double simultaneous tactile stimuli. In the
distributed spatial attention condition, K.L. omitted most of the single
tactile stimuli delivered to his left hand. In the focused attention condition,
K.L. was asked to focus his spatial attention only on his left hand. Under this
latter condition, his performance increased dramatically, suggesting that his
omissions were not due to hemianesthesia, but rather reflected left tactile
neglect. In line with the neuropsychological findings, voxel based analysis of
his grey and white matter damage confirmed significant loss in areas associated
with left-sided neglect, but sparing of the primary somatosensory cortex. This
result suggests that standard somatosensory assessment and differential
diagnosis between hemianesthesia and tactile neglect may be more accurate when
neuropsychology-based procedures are incorporated in the standard neurological
examination.
