An Immunohistochemical Study of Perivascular Plaque in Alzheimer’s Disease and Cerebral Amyloid Angiopathy

Immunohistochemical study of perivascular plaques (PPs) in 7 patients with Alzheimer’s disease (AD) and 4 with cerebral amyloid angiopathy (CAA)(CAA with dementia in 3 patients and CAA with massive cerebral hemorrhage in 1 patient) demonstrated that PPs were also a common form of amyloid β (Aβ) deposits, like SPs and CAAs, in both AD and CAA, and that they had similar immunostaining characteristics to mature senile plaques (SPs), manifesting as always positive for both Aβ42 and Aβ40 but predominant for Aβ42. In addition, PPs were always associated with AT8-positive degenerated neurites and GFAP-positive astrocytes and fibers. These findings suggest that PPs as mature plaques contribute to the development of dementia, especially in CAA with dementia which lack AD pathology. Moreover, semiquantitative analysis revealed no correlation between the number of PPs and that of SPs, but a good correlation between the number of PPs and that of CAAs, suggesting that there was a close relationship of the formation of PPs and the development of CAAs. PPs were also found around non-CAA arteries, although they were frequent around varying degrees of CAAs, suggesting that the initial Aβ42 deposits in PPs contribute to the development of CAAs

Wechsler Adult Intelligence Scale, 3rd Edition (WAIS-III): Usefulness in the Early Detection of Alzheimer’s Disease

We examined Alzheimer’s disease (AD) patients using a Japanese version of the Wechsler Adult Intelligence Scale, 3rd Edition (JWAIS-III) to clarify i) the significance of expansion of the indicated age range, ii) the characteristics of cognitive impairment in AD patients and iii) the efficacy of th neuropsychological assessment for the early detection of AD using the Digit Symbol subtest, which involves attention and episodic memory, and the Pairing supplementa-ry test, which relates to digit symbol-incidental learning. The JWAIS-III was given to 43 AD patients (12 males and 31 females; mean age, 80.9 ± 6.3 years, who fulfilled the diagnostic cri-teria for AD on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) and the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association. Severity of dementia of the patients was classified according to Functional Assessment Staging (F) as follows: 9 patients in F3 (borderline), 15 in F4 (mild AD), 12 in F5 (moderate AD), 7 in F6 (somewhat severe AD) and none in F7 (severe AD). i) Mean intelligence quotients (IQs) were: Full Scale IQ 84.3 ± 14.0, Verbal IQ 84.6 ± 12.5 and Performance IQ 86.9 ± 15.5. Comparison of IQs and subtest scores of the patients aged 75 years or older assessed by standard scores for 70 to 74 years of age, which is the upper limit of the indicated age range on the WAIS-R (the previous version of the WAIS-III), with those assessed by the standard scores for the appropriate age revealed that the former were significantly lower in IQ and all subtest scores. ii) Significant differ-ences were noted among the severities of dementia in the scores of 7 subtests for Similarities, Comprehension, Arithmetic, Digit Span, Letter-Number Sequencing, Digit Symbol and Sym-bol Search. iii) When both the Digit Symbol subtest scores of 7 points or more and the Digit Sumbol-Pairing supplementary test scores exceeding 10% of the cumulative percentile were regarded as normal, 11 of 15 (73.3%) patients in F4 (mild AD) could be detected. These find-ings suggest that i) expansion of the indicated age range in the WAIS-III allows a more valid assessment of cognitive function in AD patients, ii) a marked decline in abstract thinking and verbal problem-solving ability and relative preservation of Perceptual organization are char-acteristics of cognitive impairment in AD patients and iii) a combination of the Digit Symbol subtest with the Pairing supplementary test is useful for the early detection of AD