deToledo‐Morell 2004.
Study characteristics | |||
Patient sampling |
Primary objectives: to compare the entorhinal cortex and hippocampal volumes as predictors of conversion to AD in a group of patients diagnosed with amnestic MCI Study population: participants with amnestic MCI Selection criteria: exclusion criteria: < 65 years, neurologic, psychiatric, or systemic conditions that may cause cognitive impairment (e.g. clinical stroke, alcoholism, major depression, a history of temporal lobe seizures) Study design: prospective longitudinal |
||
Patient characteristics and setting |
Clinical presentation: amnestic MCI defined according to Petersen 2001 diagnostic criteria Age mean (SD): people with MCI who progressed to AD: 83 ± 5 years; stable MCI: 81 ± 8 years Gender (% men): MCI who progressed to AD 40%; MCI non‐converters 47% Education years mean (SD) MCI who progressed to AD: 18.4 ± 2.1; MCI non‐converters: 15.2 ± 3.1 ApoE4 carriers (%): not reported Neuropsychological tests: MMSE mean (SD): people with MCI who progressed to AD: 26.1 ± 1.4; MCI non‐converters: 28.0 ± 1.8 Clinical stroke excluded: yes Co‐morbidities: not reported Number enrolled: 27 Number available for analysis: 27 Setting: a tertiary university hospital; the Rush Alzheimer's Disease Center Country: USA Period of study: not reported Language: English |
||
Index tests |
Index test: MRI manual method for estimation of hippocampal and entorhinal cortex volumes Manufacturer: GE (Signa scanners) Tesla strength: 1.5 Assessment methods: Analyze software package (Mayo Clinic Foundation) was used for determining the volumes of ROI. Both the hippocampal and the entorhinal cortex volumes were manually segmented respectively according to deToledo‐Morrell 1997 and Goncharova 2001 Description of positive cases definition by index test as reported: not specified Examiners: all tracings were carried out by T.R.S. (who was trained to be within 95% of L.deT.‐M.) and were checked, slice by slice, by L.deT.‐M. Investigators involved in the MRI analyses were blinded to clinical information until all volumetric determinations were completed Interobserver variability: inter‐ and intra‐rater correlation coefficients, based on a sample of 10 MRI scans, were 0.97 and 0.97, respectively, for the hippocampal, 0.99 and 0.99, respectively, for the entorhinal cortex |
||
Target condition and reference standard(s) |
Target condition: AD Prevalence of AD in the sample: 10/27 (37% of cases enrolled in the study) Stable MCI or converted to other dementia: 17 (63%) Reference standard: NINCDS‐ADRDA (McKhann 1984) Mean clinical follow‐up: 3 years |
||
Flow and timing |
Withdrawals and losses to follow‐up: none reported Uninterpretable MRI results have not been reported |
||
Comparative | |||
Key conclusions by the authors | Results of the study were in agreement with post mortem pathological findings and underscored the early involvement of the entorhinal cortex in AD. Findings demonstrated the potential of sensitive neuroimaging techniques for the development of early anatomical markers of AD and for tracking, longitudinally, MCI at risk of developing AD | ||
Conflict of interests | Not reported | ||
Notes |
Source of funding: this research was supported by Grants P01 AG09466, P30 AG10161, and R01 AG17917 from the NIA, NIH 2 x 2 table: data to complete 2 x 2 table provided by the study authors |
||
Methodological quality | |||
Item | Authors' judgement | Risk of bias | Applicability concerns |
DOMAIN 1: Patient Selection | |||
Was a consecutive or random sample of patients enrolled? | No | ||
Was a case‐control design avoided? | Yes | ||
Did the study avoid inappropriate exclusions? | Yes | ||
High | Low | ||
DOMAIN 2: Index Test All tests | |||
Were the index test results interpreted without knowledge of the results of the reference standard? | Yes | ||
Did the study provide a clear pre‐specified definition of what was considered to be a "positive" result of the index test? | No | ||
Was the index test performed by a single operator or interpreted by consensus in a joint session? | Yes | ||
High | Low | ||
DOMAIN 3: Reference Standard | |||
Is the reference standards likely to correctly classify the target condition? | Yes | ||
Were the reference standard results interpreted without knowledge of the results of the index tests? | Yes | ||
Low | Low | ||
DOMAIN 4: Flow and Timing | |||
Was there an appropriate interval between index test and reference standard? | Yes | ||
Did all patients receive the same reference standard? | Yes | ||
Were all patients included in the analysis? | Yes | ||
Low |