Gm. Rettig et al., Neuropsychological outcome after unilateral pallidotomy for the treatment of Parkinson's disease, J NE NE PSY, 69(3), 2000, pp. 326-336
Objective-To assess the long term cognitive outcome of unilateral posterove
ntral pallidotomy (PVP) and the overall efficacy of the surgery.
Methods-Forty two (29 left and 13 right PVP) patients with Parkinson's dise
ase underwent neurological and neuropsychological testing before PVP and at
3 and 12 months after PVP. The neuropsychological testing battery emphasis
ed measures of verbal learning and memory, visuospatial abilities, speed of
information processing, executive functioning, and affective functioning.
Results-All patients demonstrated motor improvements after surgery during t
heir off state, and 86% of patients also showed improvements in motor funct
ioning in their on state. Repeated measures ANOVA showed significant improv
ements in confrontational naming, visuospatial organisation, and affective
functioning 3 months and 12 months after surgery, with inconsistent improve
ments in executive functioning 12 months post-PVP Patients demonstrated a t
ransient impairment in verbal memory, with verbal learning performance retu
rning to baseline 12 months post-PVP after a significant decline 3 months a
fter PVP. When three patients with lesions extending outside of the PVP wer
e excluded from the analysis, a decline in verbal fluency performance after
PVP was not found to be significant. Differences due to side of lesion pla
cement were not found on any of the cognitive measures.
Conclusions-In the largest long term follow up study reported to date, the
cognitive changes found up to a year after PVP are minimal compared with th
e robust improvements in motor function. The findings highlight the need to
investigate the relation between the specific fibre tracts affected by the
lesions and cognitive outcome.