Wang 2006.
| Study characteristics | |||
| Patient sampling |
Primary objectives: to evaluate the correlations of ApoE genotype, cognitive performance, medial temporal structure volumes, and clinical outcome in amnestic MCI Study population: MCI consecutively recruited from neurological clinics at Taipei Veterans General Hospital Selection criteria: inclusion criteria:
Each MCI patient had a CDR score of 0.5. Exclusion criteria: evidence of other neurological, psychiatric or systemic conditions that can cause cognitive impairment (e.g. stroke, alcoholism, major depression). Individuals with evidence of structural brain alterations, such as masses, cortical stroke, multiple subcortical lacunae or prominent periventricular white matter changes, were also excluded Study design: prospective longitudinal study |
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| Patient characteristics and setting |
Clinical presentations: amnestic MCI according to Petersen's criteria (Petersen 1999). Age mean (SD): MCI who progressed to AD: 78 ± 5; stable MCI: 76 ± 4 Gender (% men): MCI who progressed to AD: 63%; stable MCI: 79% Education years mean (SD): MCI who progressed to AD: 11.7 ± 5.7; stable MCI:11.7 ± 3.3 ApoE4 carriers (%): MCI who progressed to AD: 33.3 % ; stable MCI: 22.9 % Neuropsychological tests: employed; MMSE mean (SD): MCI who progressed to AD: 24.4 ± 2.1; stable MCI: 26.6 ± 2.6 Clinical stroke excluded: yes Co‐morbidities: not reported Number enrolled: 58 Number available for analysis: 58 Setting: Taipei Veterans General Hospital (Memory Clinic) Country: Taiwan Period: August 1999‐July 2003 Language: English |
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| Index tests |
Index test: MRI manual method for estimation of hippocampus and amygdale volumes Manufacturer: Magnetom Vison, Siemens Tesla strength: 1.5 Assessment methods: anatomical boundaries of the hippocampus and amygdala adopted were those defined by Lehericy (Lehéricy 1994). Description of positive cases definition by index test as reported: not specified Examiners: a single neuroradiologist performed the assessment, blinded to clinical and neuropsychological data. ICC for intra‐rater (test–retest) agreement from 12 images were 0.98 for the hippocampus and the 0.97 for the amygdala. Interobserver variability: not provided |
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| Target condition and reference standard(s) |
Target condition: AD Prevalence of AD in the sample: 19/58 (33% of enrolled participants) Stable MCI or converted to other dementia: 39 (67%) stable MCI Reference standards: NINCDS‐ADRDA criteria (McKhann 1984) Neurologists blind to the neuroimaging volumetric measurement results made clinical diagnoses at baseline. It is unclear if the blindness was respected in the follow‐up. Mean clinical follow‐up: 1.8 years |
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| Flow and timing |
Withdrawals explained and losses to follow‐up: none reported Uninterpretable MRI results have not been reported |
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| Comparative | |||
| Key conclusions by the authors | Both cognitive performance and hippocampal volume predicted decline of MCI patients. However, when time‐to‐conversion was considered as a principal outcome factor, global cognitive performance had greater significant influence on conversion time than hippocampal volume and ApoEϵ4 was not a significant predictive factor for dementia due to AD | ||
| Conflict of interests | Information not available | ||
| Notes |
Source of funding: this study was partially supported by research grants from the National Science Council (NSC91‐2314‐B‐010‐014, NSC 92‐2314‐B‐010‐031) and Taipei Veterans General Hospital (V310) 2 x 2 table: data to complete 2 x 2 table provided by the study authors |
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| Methodological quality | |||
| Item | Authors' judgement | Risk of bias | Applicability concerns |
| DOMAIN 1: Patient Selection | |||
| Was a consecutive or random sample of patients enrolled? | Yes | ||
| Was a case‐control design avoided? | Yes | ||
| Did the study avoid inappropriate exclusions? | No | ||
| 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 | |||