15 December 2010
Llebaria
G, Pagonabarraga J, Martínez-Corral M, García-Sánchez C, Pascual-Sedano B,
Gironell A, Kulisevsky J
The development of visual hallucinations (VH) is a frequent complication
of Parkinson's disease (PD). Presence of hallucinations is one of the
main risk factors associated with dementia, and severity progression of
VH mainly contributes to impaired quality of life in PD. The
neuropsychological features associated with severity progression of VH
are unknown and might help to detect patients at risk of a more severe
outcome.
We aimed to explore the neuropsychological deficits associated
with the different types of VH observed in PD, from minor hallucinations
to well-formed VH with loss of insight. Prospective study of 57 PD
patients with (n = 29) and without VH (n = 28) matched for age,
education, antiparkinsonian medications, and disease duration.
Description of VH was assessed by the Hallucinations and Psychosis item
of the MDS-UPDRS. Cognition was assessed with the Parkinson's
Disease-Cognitive Rating Scale (PD-CRS) and the Mattis Dementia Rating
Scale (MDRS).
Patients with minor VH did not differ from patients
without VH in any cognitive domain. PD patients with major VH and
insight retained performed worse on the action verbal fluency task (P < 0.04), and patients with VH and loss of insight showed a greater impairment on the PD-CRS posterior cortical score (P = 0.021) and the clock copying item (P
= 0.01). A double dissociation was found in the neuropsychological
profile of patients with VH with and without loss of insight.
While the
presence of major VH with insight retained appeared related to a
predominant frontal-striatal impairment, loss of insight was
characterized by further impairment of cognitive functions related to
posterior cortical areas. A comprehensible continuum pattern of clinical
relationships emerged among VH and cognitive functioning in PD.
