Review of publications that use the CERAD measures indicates that CERAD has had two major effects: (1) it has provided accepted standards for the clinical, neuropsychological, and neuropathologic diagnosis of AD; and (2) it has provided validated, normed measures that have been broadly used and that permit comparison across studies and settings. through summarize the main studies in which the CERAD measures have been used. In addition, the neuropsychological battery in whole or in part, continues to be used by the ADCs in their ongoing clinical and research studies (personal communication, K. Welsh-Bohmer (6 Dec 2006), J.C. Morris (7 Dec 2006)).
Epidemiological studies using CERAD batteries
Languages into which CERAD measures have been translated
The clinical, neuropsychology, and neuropathology batteries, and the Behavior Rating Scale for Dementia have been used in major epidemiological studies with diverse racial/ethnic groups (). Such uniform use in a number of different countries, and within the same country with different population groups, permits direct comparison of prevalence and incidence rates, and facilitates assessment of alternative risk factors. By using uniformly operationalized diagnostic criteria, and comparable assessment measures (we recognize that measures may need to be adapted to the cultural experience of those who are evaluated), any differences found are likely to be true differences, or at least not artifacts of the assessment itself.
The clinical and neuropsychology batteries have also been used in clinical trials (), yielding information of national and international importance on the impact of hormone replacement therapy, and (provided the study is funded), on the impact of selenium and vitamin E in preventing AD. We have not included drug trials carried out by pharmaceutical companies. While we know that specific tests included in the CERAD neuropsychology battery have been used, we are not privy to the intervention being examined, or to the findings. Such use is, however, an indication of the perceived value of these measures. Finally, some entrepreneurs have selected tests in the neuropsychology battery for on-line outreach, inviting persons concerned about their memory to be evaluated by telephone, with a potential diagnosis given in short order. Evaluation under medical supervision is also available. The appropriateness and impact of this approach has not been determined.
Major clinical trials that have used CERAD materials
lists the types of samples for which norms have been developed. They include clinic-based samples of diverse race/ethnicity in the U.S., and clinic-based norms for German-speaking countries. Norms have also been developed for internationally distributed community-based samples. The presence of such norms facilitates appropriate comparison: newly evaluated community residents can be compared with other community residents of comparable age, race/ethnicity, and education; patients at tertiary medical care centers can be compared with other patients at the same types of centers.
Norms -- representative selection
The CERAD neuropsychology battery (sometimes in whole, sometimes in part), has been used with various groups who, in addition to those listed in –, include Native Americans,53
older Israelis (in Hebrew),54,55
elderly in Colombia,56,57
and older persons in India, China, Southeast Asia, Latin America and the Caribbean, and Africa.58,59
The clinical battery has been referenced as a standard by several clinical studies that indicate that they used NINCDS/ADRDA and CERAD criteria for AD. In those instances, however, it is difficult to know whether the CERAD clinical battery or the CERAD clinical criteria were used. Compared to NINCDS/ADRDA, CERAD clinical criteria are stricter regarding duration of memory loss, but more lenient regarding older age.
shows the languages into which CERAD measures have been translated. The multiple translations (typically done in the conventionally approved manner with back translation) facilitate testing of patients within countries such as the U.S. and Canada that have a multilingual population, as well as facilitating cross-national comparisons. We have not included English as spoken in Australia in this table, but we would mention that, even when ostensibly the same language is spoken in two different locations, it may be important to evaluate the measure in each location if there are indications that terms are differently understood in the different locations, or may be understood differently by different residents of the same location. To make sure that the measures remain acceptable (and hopefully equivalent), item order has sometimes been changed (e.g., for the Behavior Rating Scale for Dementia in Arabic), items have been substituted (e.g., in the abbreviated Boston Naming task used in Finland), and different words used (e.g., in the “American” vs. “European” Spanish translations of the Word List).