The authors report the underestimated cognitive, mood, and behavioral complications in patients who have undergone bilateral contemporaneous
pallidotomy, as seen in their early experience with functional neurosurgery for
Parkinson's disease (PD) that is accompanied by severe motor fluctuations before pallidal stimulation. Four patients, not suffering from
dementia, with advanced (Hoehn and Yahr Stages III-IV), medically untreatable PD featuring severe "on-off" fluctuations underwent bilateral contemporaneous posteroventral
pallidotomy (PVP). All patients were evaluated according to the Core Assessment Program for Intracerebral
Transplantations (CAPIT) protocol without positron emission tomography scans but with additional neuropsychological cognitive, mood, and behavior testing. For the first 3 to 6 months postoperatively, all patients showed a mean improvement of motor scores on the Unified
Parkinson's Disease Rating Scale (UPDRS), in the best "on" (21%) and worst "off" (40%) UPDRS III motor subscale, a mean 30% improvement in the UPDRS II
activities of daily living (
ADL) subscore, and 60% on the UPDRS IV complications of treatment subscale.
Dyskinesia disappeared almost completely, and the mean daily duration of the off time was reduced by an average of 60%. Despite these good results in the CAPIT scores, one patient experienced a partially regressive corticobulbar syndrome with
dysphagia,
dysarthria, and increased
drooling. No emotional lability was found in this patient, but he did demonstrate severe bilateral postoperative pretarsal
blepharospasm (
apraxia of eyelid opening), which interfered with walking and which required treatment with high-dose
subcutaneous injections of
botulinum toxin. No patient showed visual field defects or
hemiparesis, but postoperative depression, changes in personality, behavior, and executive functions were seen in two individuals. Postoperative abulia was reported by the family of one patient, who lost his preoperative aggressiveness and drive in terms of
ADL, speech, business, family life, and hobbies, and became more sleepy and fatigued. One patient reported postoperative mental automatisms, such as compulsive mental counting, and circular thoughts and reasoning during off phases; postoperative depression was found in two patients. However, none of the patients demonstrated these symptoms during intraoperative
microelectrode stimulation. These findings are compatible with previous reports on bilateral pallidal lesions. A progressive lowering of UPDRS subscores was seen after 12 months, consistent with the progression of the disease. Bilateral simultaneous
pallidotomy may be followed by emotional, behavioral, and cognitive deficits such as depression,
obsessive-compulsive disorders, and loss of psychic autoactivation-abulia, as well as disabling corticobulbar dysfunction and
apraxia of eyelid opening, in addition to previously described motor and visual field deficits, which make this surgery undesirable even though significant improvement in motor deficits can be achieved.