TABLE 1.

An overview of PET studies reporting cerebral metabolic rate for glucose (CMRg) in mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Owing to the different study designs, it is difficult to derive the mean difference in CMRg in AD versus controls but it is on the order of 25%, and somewhat less in MCI.

Reference	n in each group	Atrophy correction	CMRga
Frackowiak et al (1981)208	n = 14 HC n = 13 AD n = 9 VD	No	28% ↓ in grey matter 23% ↓ in white matter for AD & VD
Benson et al (1983)209	n = 16 HC n = 8 AD	No	↓ 49% for AD
Cutler et al (1985)210	n = 25 HC n = 5 mild to moderate AD n = 2 severe AD	No	25–50% ↓ for severe AD in frontal, parietal, temporal, occipital lobes compared to mild-mod AD & HC
Rapoport et al (1986)211	n = 10 HC n = 47 mild to moderate AD	No	18–31% ↓ for AD
Chawluk et al (1987)212	n = 17 HC n = 24 AD	Yes	8% ↓ for AD
Alavi et al (1993)213	n = 17 HC n = 20 AD	Yes	11 % ↓ for AD
Mielke et al (1994)214	n = 13 HC n = 20 AD	No	↓ for AD in temporoparietal and occipital cortex
Metzler et al (1996)215	n = 10 HC n = 8 AD	Yes	↓ for AD in frontal, temporal and posterior parietal lobes
Hock et al (1997)52	n = 17 HC n = 19 AD	No	↓ for AD in parietal lobe
Ibanez et al (1998)48	n = 19 HC n = 5 mild AD n = 6 moderate AD n = 4 severe AD	Yes	↓ for AD in precuneaus and posterior cingulate cortex
Mosconi et al (2005)50	n = 11 HC n = 13 MCI n = 12 AD	Yes	18% ↓ for MCI 27% ↓ for AD in hippocampus compared with HC
Minoshima et al (2007)216	n = 22 HC n = 8 AD	Yes	20–21% ↓ for AD in posterior cingulate and cinguloparietal transitional area
Li et al (2008)37	n = 7 HC n = 13 aMCI n = 17 AD	No	in AD; gray matter (11% ↓), hippocampus (30% ↓), inferior parietal lobe (15% ↓), middle frontal gyrus (12% ↓), posterior cingulate (17% ↓) in aMCI; hippocampus (14% ↓) and inferior parietal lobe (11% ↓)
Del Sole et al (2008)58	n = 7 HC n = 16 aMCI n = 14 AD	No	↓ for AD in posterior cingulate, precuneaus, & parietal & temporal lobes ↓ for aMCI in posterior cingulate
Ishii et al (2009)66	n = 42 MCI who converted to AD within 5 y	No	↓ for AD in right cingulate, left inferior lobe & left temporal gyrus

HC – healthy controls (commonly but not always well matched for age, education). Comorbidities, i.e. hypertension, not always excluded or controlled for, especially in earlier studies.

MCI – mild cognitive impairment, type not specified

aMCI – amnestic MCI

AD – Alzheimer’s disease, usually defined as 〈probable〉 AD, Most common criteria are those of the National Institute of Neurological and Communicable Diseases and Stroke, Alzheimer’s Disease and Related Dementias Association (NINCDS-ADRDA)

CMRg – cerebral metabolic rate for glucose

VD – vascular dementia

^adifference versus healthy controls