(May 23, 2012) A study just published by French researchers sheds additional light on the anatomical basis of anosognosia.
Ten patients with schizophrenia and anosognosia were compared to 21 patients with schizophrenia but without anosognosia (i.e., patients with good awareness of their illness) and also to 18 control individuals without schizophrenia.
All underwent testing to measure their cerebral blood flow. The patients with anosognosia were found to have significantly decreased blood flow to the precuneus region of the brain. The precuneus is part of the superior parietal lobule and is known to have functions associated with our ability to think about ourselves. Thus it is not surprising that damage to this area is associated with anosognosia.
Anosognosia, or unawareness of illness, is a common problem in several brain diseases including Alzheimer’s disease, Huntington’s disease, strokes involving particular parts of the brain, schizophrenia and bipolar disorder with psychotic features. The anatomical basis of anosognosia has been well described. Studies of anosognosia in schizophrenia have reported that the prefrontal and inferior parietal areas, and connections between these areas, are involved, especially when the disease is on the right side of the brain.
These pictures show the differences in blood flow in the precuneus in an individual with altered insight (anosognosia) compared with an individual with preserved insight (no anosognosia).
(Pictures courtesy of Dr. Eric Guedj, Dept. of Nuclear Medicine, Hospital de la Timone, Marseille, France).