Clinical features of the alien hand syndrome:
(1) The patient has uncontrolled, involuntary and/or automaton-like movements of a hand.
(2) The patient does not perceive that the hand belongs to him/her, but rather seems "alien".
Risk factors for the involuntary movements:
(1) fatigue
(2) anxiety
(3) an object being nearby
Conditions associated with the alien hand syndrome:
(1) damage to the corpus callosum, including a partial callosectomy
(2) medial frontal lobe lesions
(3) progressive supranuclear palsy
(4) posterior cerebral lesion (pre- and postcentral gyri, corticobasal degeneration)
AHS may be subclassified:
(1) frontal: reflexive grasping, groping and/or compulsive manipulation of tools affecting the dominant hand
(2) callosal: intermanual conflict during behaviors requiring dominant-hemisphere control, which may be viewed as a result of hemispheric disconnection
(3) mixed frontal and callosal
(4) posterior
|
Site of Damage
|
Clinical Findings
|
|
mesial frontal and anterior callosal (genu and rostral body)
|
frontal AHS (contralateral)
|
|
isolated damage to callosal midbody and isthmus
|
callosal AHS
|
|
medial frontal and extensive damage to corpus callosum
|
mixed frontal and callosal AHS
|
|
posterior cerebral lesion without damage to corpus callosum
|
posterior AHS
|
