More than three quarters of this representative PD cohort developed dementia during the 8-year study period. Early hallucinations and akinetic-dominant PD were associated with an increased risk of dementia.

Background: In studies of mild cognitive impairment (MCI) in Parkinson disease (PD), patients

The findings demonstrate a twofold increase in the proportion with cognitive impairment in subjects with early, untreated Parkinson disease (PD) compared to controls. This has implications for diagnosis and management of PD. AD = Alzheimer disease; aMCI-MD = amnestic multiple-domain MCI; aMCI-SD = amnestic single-domain MCI; CVLT-2 = California Verbal Learning Test II; IQCode = Informant Questionnaire on Cognitive decline in the elderly; MADRS = Montgomery and Aasberg Depression Rating Scale; MCI = mild cognitive impairment; MMSE = Mini-Mental State Examination; naMCI-MD = non-amnestic multiple-domain MCI; naMCI-SD = non-amnestic single-domain MCI; PD = Parkinson disease; RR = relative risks; UPDRS = Unified Parkinson's Disease Rating Scale; VOSP = Visual Object and Space Perception Battery.

Both motor and neuropsychiatric symptoms contributed to institutionalization, but the presence of hallucinations was the strongest predictor. This finding indicates it is possible that effective treatment of hallucinations may reduce the need for institutionalization in patients with Parkinson's disease.

Patients with PD have an almost sixfold increased risk for becoming demented compared with subjects without PD.

The aim of this study was to establish the rate of progression from mild cognitive impairment (MCI) to dementia in patients with Parkinson's disease (PD). PD patients without dementia were recruited in 1997 from an ongoing prospective epidemiological study. The assessment included neurological and psychiatric examinations, a clinical interview based on the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) criteria for dementia, and a battery of neuropsychological tests. PD was diagnosed according to established criteria, dementia was diagnosed according to the DSM-III-R criteria, and subtypes of MCI were classified according to modified Petersen's criteria. Seventy-two nondemented PD patients were included. A total of 34 were cognitively intact, whereas 38 were diagnosed with MCI (amnestic, n = 6; single nonmemory domain, n = 17; multiple domains slightly impaired, n = 15). Fifty-nine patients (82%) completed follow-up examination 4 years later, and 18 (62%) of the patients with MCI and 6 (20%) of the cognitively intact PD patients were demented (P = 0.001). Single domain nonmemory MCI and multiple domains slightly impaired MCI were associated with later development of dementia (P = 0.003; P = 0.04), whereas amnestic MCI subtype was not (P = 0.76). We conclude that patients with PD and MCI had a higher risk of developing dementia than cognitively intact PD patients, suggesting that MCI in PD is an early manifestation of dementia. However, these findings should be interpreted with caution due to the relatively small number of subjects included in this study.

Objectives-Disturbances of cognition and emotion are common in patients with Parkinson's disease. Most previous studies of psychopathology in Parkinson's disease have focused on a single psychiatric diagnosis or condition. The objective of this study was to describe the range of neuropsychiatric symptoms in a representative sample of patients with Parkinson's disease. Methods-The sample of 139 patients was drawn from an epidemiological study of Parkinson's disease in Rogaland county, Norway, and represented 93% of those who had survived during the 4 years since the initial assessment. The diagnosis of Parkinson's disease was based on published criteria. Neuropsychiatric symptoms were assessed using the neuropsychiatric inventory, a caregiver based structured interview, which assesses severity and frequency of 10 psychiatric symptoms present during the past month. Results-At least one psychiatric symptom was reported in 61% of the sample. The most common behaviours were depression (38%) and hallucinations (27%), and the least common symptoms were euphoria and disinhibition. The highest mean scores were found for depression, apathy, and hallucinations. Factor analysis showed that hallucinations, delusions, and irritability clustered into one factor, and apathy and anxiety constituted another factor. Psychiatric symptoms were more common among patients living in nursing homes compared with home dwelling patients, and correlated with stage of disease and cognitive impairment, but not with age or duration of disease. No relation to left or right sided parkinsonism was found. Conclusion-This study emphasises the importance of psychiatric symptoms in Parkinson's disease, which were present in most patients. Clinicians should focus on the emotional and cognitive disturbances in addition to the motor manifestations of the disease. (J Neurol Neurosurg Psychiatry 1999;67:492-496)

The objective of this study was to assess the temporal relationship between changes in predominant motor symptoms and incident dementia in Parkinson's disease (PD). A community-based sample of 171 nondemented patients with PD was followed prospectively and examined at baseline and after 4 and 8 years. The motor subtype of Parkinsonism was classified into tremor-dominant (TD), indeterminate, or postural instability gait difficulty (PIGD) subtype at each visit, based on defined items in the Unified Parkinson's Disease Rating Scale, subscales II and III. Dementia was diagnosed according to DSM-III-R criteria, based on clinical interview, cognitive rating scales, and neuropsychological examination. Logistic regression was used to analyze the relationship between subtype of Parkinsonism and dementia. Transition from TD to PIGD subtype was associated with a more than threefold increase in the rate of Mini-Mental State Examination decline. Compared to patients with persistent TD or indeterminate subtype, the odds ratio for dementia was 56.7 (95% CI: 4.0-808.4; P = 0.003) for patients changing from TD or indeterminate subtype to PIGD subtype, and 80.0 (95% CI: 4.6-1400.1; P = 0.003) for patients with persistent PIGD subtype. Patients with TD subtype at baseline did not become demented until they developed PIGD subtype, and dementia did not occur among patients with persistent TD subtype of Parkinsonism. In a substantial proportion of PD patients who develop postural instability and gait disorder during the course of the disease, this transition is associated with accelerated cognitive decline and highly increased risk for subsequent dementia. These findings raise the question whether PIGD and dementia share common or parallel neuropathology.