With the single exception of a test repeated at age 26 years (reading comprehension), cognitive function was not assessed from adolescence until age 43 years, when there was a shift away from tests of intellectual ability and towards the assessment of functional cognitive performance (memory, processing speed, and motor praxis). Some of these tests were repeated at age 53 years, with the addition at this age of a verbal ability test (the NART) to link back to related tests in childhood.
Age 26 years (1972):
The Watts-Vernon Reading Test, first given at age 15 years, was re-administered at age 26 years with an additional 10 items of increased difficulty to avoid a ceiling effect (Rodgers, 1986).
Age 43 years (1989):
Five types of cognitive test were devised by the NSHD:
Age 53 years (1999):
At this age the verbal learning and timed letter search tasks used at age 43 years (nos. 1 and 4 above) were re-administered, although the latter used only one trial. In addition, a delayed recall condition was added to the verbal learning task, using an interval of approximately 90 seconds. Tests 2, 3 and 5 above were not re-administered at 53 years. However, four new tests were given at this age:
Age 60-64 years (2006-10):
At this age the verbal learning and timed letter search tasks, which had been used at age 43 and 53 years (nos. 1 and 4, age 43), were re-administered, although the latter used only one trial. A reaction time test was also undertaken at this age.
Age 68-70 years (2014-16):
At this age the verbal learning and timed letter search tasks, which had been used at age 43, 53 and 60-64 years (nos. 1 and 4, age 43) were re-administered, although the latter used only one trial. A finger-tapping test (number of taps with index finger in a set time, both hands tested separately) also took place.
There was also a new cognitive test given at this age:
1. Addenbrooke's Cognitive Examination-III (ACE-III). The ACE-III is an extension to the Mini Mental State Examination (MMSE), testing five cognitive domains: attention/orientation, memory, language, verbal fluency, and visuospatial skills. Scores are evaluated for each of the domains, as well as an overall score out of 100, with a higher score denoting better cognitive function. As an MMSE equivalent subset is contained within the ACE-III, a score for this can also be generated. The examination was mostly conducted using the ACEmobile app, which was installed on an ipad, providing prompts to help guide the interviewer through the assessment. Paper test sheets were used where necessary (e.g. for drawing tasks).
Further information on the mental ageing research programme is available on the public LHA website.
You can obtain a list of the standard topic variables to use in an NSHD data sharing request by selecting the link at the end of this page.
Please Note that the adult cognitive ability standard basket contains the most commonly-used summary variables on this topic. The variables that are most often used longitudinally, or as cross-sectional covariates, are verbal memory (word list) summaries WLT89, WLT99, WLT09 and WLT15x, and the visual search speeds CANSP189, CANSP99, VSP09 and VSP15x (note change of variable name stem). CANSP189 is used for the age 43 measure rather than the average of the visual search test speeds as the test was repeated at this age, but only took place once in later years.
For the full, detailed variable list please investigate this subject on Skylark.
More information is available on this topic - including the main variable naming conventions and some value labels.
HTML version of the standard variables to view