Hemispatial Neglect

Question 1

What is hemispatial neglect?

Answer 1

Loss of awareness of stimuli in contralesional side of space, as a result of a stroke.

Question 2

In which hemisphere does a lesion most commonly cause hemispatial neglect

Answer 2

Right - more common and persistent with lesions in the right hemisphere

Question 3

Why does hemispatial neglect impact the contralesional side of space?

Answer 3

Localisation of function - left field of vision localised to right hemisphere

Question 4

What is the most common form of stroke? According to whom?

Answer 4

Stein et al. (2007) 51% of 2213 ischemic stroke patients had strokes localised to the middle cerebral artery (MCA)

Question 5

Can hemispatial neglect be attributed to sight loss?

Answer 5

No, neglect can occur in both visual and tactile modalities (Marsh & Hillis, 2008)

Question 6

Is hemispatial neglect purely object centered?

Answer 6

No, it can be object centered but can also operate on internal representations (Bisiach & Luzatti, 1978). Patients may present with either and can sometimes present with both (Marsh & Hillis, 2009)

Question 7

How is neglect severity controlled?

Answer 7

Modulated by the properties of neglected stimuli, unconscious processing of contralesional stimuli - capture of attention by fear related stimuli (Vuilleumier & Schwartz, 2001)

Question 8

Implications?

Answer 8

Spatial attention as a competitive process - patients have trouble disengaging from stimuli on ipsilesional side (Posner, 1984)