To the Editor.
—We would like to comment on the article by Johnson et al1 that appeared in the April 1988 issue of the Archives.1 The authors reported that single photon emission computed tomography (SPECT) brain imaging with iofetamine hydrochloride I 123 was able to reflect dementia severity in patients with Alzheimer's disease (AD). To determine dementia severity, they used a global estimate of functional disability on a 4-point scale.Dividing a group of patients with AD into several groups based on functional impairment seems rather artificial. The great range of overlap in score on the Blessed Dementia Scale2 between the four groups (Table 1 in the article) seems to support this. In our opinion, a comparison of the whole spectrum of dementia should be made with SPECT abnormalities. Further-more, dementia severity was determined by estimating functional disability, without referring to previous ability. We think that the
Haan J, Weinstein HC, Van Kroonenburgh MJPG, Van Royen EA, Lanser JBK, Derix M, Buruma OJS, Hijdra A. Single Photon Emission Computed Tomography in Alzheimer's Disease. Arch Neurol. 1989;46(11):1165–1166. doi:10.1001/archneur.1989.00520470015009