A neurological disorder
From NORD's rare diseases database: "Apraxia is a neurological disorder characterized by the inability to perform learned (familiar) movements on command, even though the command is understood and there is a willingness to perform the movement. Both the desire and the capacity to move are present but the person simply cannot execute the act. Patients with apraxia cannot use tools or perform such acts as tying shoelaces or button shirts etc. The requirements of daily living are difficult to meet. Patients ... are almost invariably dependent."
