Can mirrors alleviate visual hemineglect?
Following right hemisphere stroke, many patients display an indifference to objects and events in the left side of the world ('neglect'). Here, we describe a new technique that might help accelerate recovery from neglect. The patient sits at a table and a mirror is propped vertically on the patient's right side in the parasagittal plane, so that when the patient rotates his head rightward and looks into the mirror, he sees the neglected side of the world reflected in the mirror. Our question was: since the sensory information was now coming from the non-neglected left side, would this somehow make him overcome the neglect? In pilot experiments, two types of responses were seen: (a) In one subset of patients the presence of the mirror seemed to enhance the patients' awareness of the neglected field, so that they reached correctly for an object that was shown in the neglected field. Will repeated practice with this task accelerate recovery from neglect? (b) The second group of patients kept reaching into the mirror to grasp the reflection or kept groping behind the mirror ('mirror agnosia'). If the mirror was placed in the coronal position and the object placed behind their head, then some of these patients (from group B) reached correctly for the object. Quite apart from its obvious theoretical implications, we believe this technique might provide a new approach for the treatment of visual hemineglect.