Here’s an illustrative example from a conversation with FD, an elderly woman who had had a right hemispheric stroke one week before, leaving her paralyzed on the left side and confined to a wheelchair:
How are you feeling today?
FD: I’ve got a headache. You know, doctor, I’ve had a stroke so they brought me to the hospital.
Can you walk?
FD: Yes (FD had been in a wheelchair for the past week, and cannot walk)
Mrs D, hold out your hands. Can you move your hands?
Can you use your right hand?
Can you use your left hand?
Are both hands equally strong?
FD: Yes, of course they are equally strong.
Mrs D, point to me with your left hand.
FD: (Her hand lays paralyzed in front of her).
Mrs D, are you pointing to my nose?
Can you see it pointing?
FD: Yes, it is about 2 inches from your nose.
Mrs D, can you clap?
FD: Yes, of course I can clap.
Mrs D, will you clap for me?
FD: (She proceeded to make clapping movements with her right hand, as if clapping with an imaginary hand near the midline)
Are you clapping?
FD: Yes, I am clapping.
He described two patients with left hemiplegia who didn’t know they were paralyzed. The word comes from the Greek words nosos, “disease”, and gnosis, “knowledge”.
Affected patients deny their deficit, and overestimate their abilities, they state that they are capable of moving their paralyzed limb and that they are not different than normal people.
Their false belief of normality persists despite logical arguments and contradictory evidence – they may even produce bizarre explanations to defend their convictions.
If they admit any impairments, they will attribute them to other causes (i.e. arthritis, tiredness, etc.).
But, this syndrome is not only seen with hemiplegia.
Visual anosognosia or Anton-Babinski syndrome is a rare neurological condition related to cortical blindness. Affected patients deny their blindness and affirm adamantly that they are capable of seeing. The clinical presentation includes confabulations – instead of admitting blindness, they will make up answers when asked about what they see.
Mr Magoo is a great TV example of Anton’s syndrome – unaware of his loss of vision, he misinterprets and confabulates his way into trouble.
Anosognosia may occur as part of receptive or Wernicke’s aphasia – affected patients cannot monitor and correct their own speech errors and may appear angry and frustrated when the person they are speaking to fails to understand them.
Watch this lecture, by Dr V. S. Ramachandran for more information on this fascinating syndrome: