Summary

We describe the clinical and single photon emission computerized tomography (SPECT) characteristics of nine patients with parkinsonian-dementia (PD) and contrast their clinical and SPECT characteristics with nine MMSE matched Alzheimer's disease (AD) patients. In six of the PD patients there was pathological confirmation of the diagnosis while in three others the diagnosis was based upon the clinical presentation. The PD patients significantly differed from the AD patients due to the high frequency of visual hallucinations, delusions, and atypical (SPECT) patterns. The clinical and SPECT patterns in PD differ from AD.

Introduction

There is an emerging literature on the neurologic (Perry et al., 1989; Crystal et al., 1990), neuropsychiatric (Perry et al., 1990a and 1990b), neuropsychological (Sakahian et al., 1988; Sahgal et al., 1992), neurochemical (Perry et al., 1990b,c; Dickson et al., 1991) and neuropathologic (Hansen et al., 1990; Dickson et al., 1991; Kosaka, 1993) features of patients who present with a mixture of parkinsonism and dementia (PD). There are three differing hypotheses regarding the classification of these PD patients. One theory emphasizes that senile plaques are commonly found with PD and suggests that PD patients are part of the spectrum of Alzheimer's disease (AD) (Hansen et al., 1990). In contrast, Perry et al. (1989) have hypothesized that the cortical Lewy bodies found at pathology in PD represent a unique disorder for which they coined the term senile dementia of the Lewy body type (SDLT).