Seguridad

Participants were invited to come to DCU to undergo a once-off face-to-face cognitive evaluation and to complete the survey employed in Study 1. The PRMQ, the HADS and the questions relating to health, sleep and sociodemographic information employed in Study 1 were also administered as part of Study 2 (see above for details).

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Objective cognitive assessment involved the completion of a number of objective cognitive tests selected for this study because:

1. they have been recommended for use in Primary Care, both here in Ireland, by the ICGP (see Foley & Swanwick, 2014 and Chapter 2) and in the USA, by the Alzheimer’s Association (see Cordell et al., 2013 and Chapter 2) (Mini-Cog: Borson et al., 2000 and GPCOG, Brodaty et al, 2002)

o Note: Although, as noted in Chapter 2, the Memory Impairment Screen (MIS) (Buschke et al., 1999; Kulansky et al., 2002) was also recommended by both the ICGP and by the Alzheimer’s Association, it was not included in the test battery used in this Study as the assessment tool does not assess multiple domains of cognition. As noted in Chapter 2, the MIS assesses delayed verbal memory (word recall) only and does not, therefore, fulfil the requirements of a good assessment tool as outlined by Cullen et al. (2013).

2. because it represents the most widely used brief cognitive assessment tool (MMSE, Folstein, Folstein & McHugh, 1975)

3. because it assesses the often-neglected domain of prospective memory (PM) which was considered to be a limitation of many studies (Cambridge Prospective Memory Test, CAMPROMPT; Wilson & Wilson, 2005)

4. because it was required for interpreting CAMPROMPT scores (National Adult Reading Test, Second Edition, NART; Nelson & Wilson, 1991)

Each of these tests is described in detail next.

90 3.2.3.2.1 Mini-Cog (Borson et al., 2000)

The Mini-Cog takes 2-4 minutes to administer and consists of two items; a 3-word memory item and a clock-drawing test, allowing a maximum of score of 5. The clock-drawing task is scored by assigning 2 points to each correctly drawn clock or 0 points for an incorrect clock. Clock drawings are scored as normal if all numbers 1-12, each only once, are present in the correct order and direction (clockwise);

two hands of any length are present, pointing to the correct time. Clock drawings lacking any of these elements are assigned 0 points, and refusal or inability to draw a clock was scored as abnormal. Delayed word recall is scored out of 3.

It is recommended that a cut-off point of <3 on the overall test, be used, with scores of 3-5 reflecting absence of obvious impairment. Scores of 0-2 are considered to be in the probably impaired range.

Scoring criteria are as follows: 3 recalled words + normal clock: negative for cognitive impairment; 1-2 recalled words + normal CDT: negative for cognitive impairment; 1-2 recalled words + abnormal CDT:

Positive for cognitive impairment; 0 recalled words: Positive for cognitive impairment (Borson, Scanlan, Brush, Vitaliano, & Dokmak, 2000; Borson, Scanlan, Chen, & Ganguli, 2003; Riley McCarten et al.

(2012). It has a reported pooled sensitivity of 76% (which is lower than the MMSE; 79%) and, pooled specificity of 89% (similar to the MMSE). Therefore, although the Mini-Cog has good inter-rater reliability (0.93-0.95), and is shorter than the MMSE, it offers little advantage over the MMSE (Borson et al., 2003). The Mini-Cog also lacks test-retest reliability data, so is not useful for monitoring disease progression or rating severity (Velayudhan et al., 2014).

3.2.3.2.2 GPCOG (Brodaty et al., 2002)

Both the ICGP and the Alzheimer’s Association have recommended the GPCOG. More recently, its use was further advocated by Yokomizo et al., (2014). Their review of screening instruments recommended the GPCOG as one of the instruments most reliable and suitable for the detection of dementia in primary care (Yokomizo et al., 2014).

As noted in Chapter 2, the GPCOG is a 6-item cognitive screening tool developed by Brodaty et al., (2002) as a brief, reliable screening tool suitable for administration in the busy primary care setting. It typically takes approximately 5 minutes to complete. There are two components: a cognitive assessment conducted with the patient, and an informant questionnaire, which is considered necessary only if the results of the cognitive section are equivocal, i.e. score of 5-8 inclusive). The test consists of an evaluation of time orientation (Max 1 point), a clock drawing task to evaluate visuospatial functioning and executive function processes (max 2 points), information retrieval (report of a recent news event) (max 1 point) and a delayed recall task (recall of a previously presented name and address)

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(max score 5 points). Thus, scores can range from 0-9. For individuals requiring an informant questionnaire, a score of 3 or less out of 6 in the informant section indicates cognitive impairment (Brodaty, Kemp and Low, 2004). Areas covered in the informant interview include memory, word finding difficulties, trouble managing finances, difficulties managing medication independently and needing assistance with transportation.

GPCOG is considered to perform well within the primary care setting and is psychometrically robust and free of educational bias. Results >8 on the GPCOG patient section are assumed to reflect those of an individual who is cognitively intact whilst scores <5 indicates impairment and standard investigations are recommended.

It has a reported pooled sensitivity of 82-85%, a specificity of 83-86%, a positive predictive value (95%

CI) of 0.71 and a negative predictive value of 0.92 and higher (Yokomizo, Sanz Simon and de Campos Bottino, 2014). While scores have been shown to be affected by depression and education in people with DSM-IV diagnosed dementia (Broadty, Kemp & Low, 2004), the GPCOG has been reported to be minimally affected by education, self-reported depression and gender (Brodaty et al., 2004, Yokomizo et al., 2014). A community-based study by Basic et al., (2009) found that GPCOG scores were influenced by depression as measured by the Geriatric Depression Scale (GDS). However, it is worth noting that in the sample of 151 participants, 58 (38.4%) had dementia, which may explain the significant predictive effect of depression on the GPCOG in that study.

In total, the GPCOG takes about 6 minutes to administer. It has strong performance on sensitivity and specificity versus MMSE in detecting dementia in a typical primary care population (Ismail et al., 2009).

It was noted nonetheless that the GPCOG showed variation in diagnostic ability with age, gender and education (Brodaty et al., 2004). Moreover, it has been found to have a misclassification rate the same or less than that of the MMSE (Milne et al., 2008). There is little information to date about the diagnostic accuracy of the GPCOG for MCI. Overall, however, it is regarded as brief, easily administered, well-accepted by clinicians, efficient and minimally affected by education, sex and race (Milne et al., 2008). There is, however, a need for further study of the GPCOG in populations representative of a primary care setting (Holsinger et al., 2007).

3.2.3.2.3 MMSE (Folstein, Folstein & McHugh, 1975)

As indicated in Chapter 2, the MMSE is the most commonly used cognitive test tool in General Practice (>50% of GPs use it; see for example, Milne et al., 2008) and in clinical and research settings (Mitchell et al., 2009). It is regarded as a measure of global cognitive functioning and it has been validated in

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both primary care and specialist settings. The original authors found it had high internal consistency, high test-retest reliability and high inter-observer reliability (Folstein et al., 1975).

The MMSE contains 11 items, measuring orientation, immediate memory, attention, calculation, recall, various aspects of language and visuospatial skills. It takes approximately 12 minutes to administer, thus it is reported by many GPs as too long for administration in the busy primary care setting (Glasser, 1993). It is scored on a scale from 0 to 30, with a score of <24 taken to be suggestive of dementia.

Scores may, however, be difficult to interpret and the test shows age, cultural and educational bias (Cullen et al., 2007).

The limitations of the MMSE, particularly in relation to low sensitivity to mild cognitive deterioration were detailed in Chapter 2. Additional limitations include the lack of sensitivity in detecting early dementia, MCI, frontotemporal dementia (FTD) and dementia with Lewy Bodies (Velayudhan et al., 2014), as well as the absence of items testing executive functions. It is, nonetheless included here as a benchmark against which to judge the other assessment tools.

3.2.3.2.4 CAMPROMPT (Wilson & Wilson, 2002).

The CAMPROMPT represents one of just two commercially available standardised objective assessments of complex prospective memory (PM). This 25-minute test is comprised of three time-based and three event-time-based (one focal and two non-focal) items embedded within a series of attention-demanding puzzles that serve as an ongoing task, e.g. “when there are seven minutes left, remind me not to forget my keys” and “when you come to a quiz question about (television show), give me this book.”

Participants are allowed to engage in any external strategies they like to help them remember, including taking notes, and are provided with a pen and paper. A digital countdown timer and analogue clock are used. The time intervals between being asked to do the task and responding properly are balanced across cueing conditions. Each item is scored between 0 and 6, therefore each scale (time;

event) total is 18 and the maximum score for the test as a whole is 36, with higher scores reflecting better performance.

The exact procedures for administering the CAMPROMPT test were adhered to as outlined in the CAMPROMPT manual. During the test, the tester’s responses to the participant’s responses depend on whether the right action was carried out at the right time. The instructions on how to respond to the actions of participants on the CAMPROMPT test were adhered to as per the CAMPROMPT manual instructions. Each of the PM tasks was given a score according to the pattern of responding described

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in the manual. On the record form, each pattern of response was recorded using the letters A to H, later translated into marks of 6, 4, 2, 1 or 0.

If an examinee spontaneously carried out the correct action at the correct time (Score A), this was awarded 6 marks. If an examinee needed a single prompt before carrying out the correct action (Score B or D), this was awarded 4 marks. If an examinee needed two prompts (whether to remember it is time for a task or to remember the correct task) this was awarded two marks (score C or E). If an examinee needed a prompt to remember it is time to do a task, then remembered that there is something to do, but still failed to carry out the task even after two prompts (Score F), or if an examinee failed to remember it is time to do a task even after prompting, and needs prompting to carry out the correct task (Score G), this is awarded a single mark. If an examinee failed to remember it is time to do a task even after being prompted twice, so that the correct task is still not carried out (Score H), this gains 0 marks. Thus, total score the three time-based tasks and three event-based tasks can range from 0 – 18, and the total score for the six tasks can range from 0 – 36.

The CAMPROPMPT has been reported to have very high inter-rater reliability of 0.998 (Pearson) and moderate test-retest reliability of 0.64 (Kendell’s Tau-b; Wilson et al., 2005). Delprado et al., (2012) found moderate inter-item reliability, with a Cronbach’s alpha coefficient of 0.75, indicating good internal consistency.

Of direct relevance to this Study, Foley (2007) found a significant negative relationship between CAMPROMPT performance and subjective ratings of memory using the PRMQ in people with dementia.

Foley (2007) also found that cognitively impaired older adults in her study performed better on the CAMPROMPT than on the Rivermead Behavioural Memory tests of PM. It should be noted, however, that the sample of cognitively impaired older adults in her study were of heterogeneous etiology and likely at various stages of decline.

Delprado et al. (2012), in their study assessing the clinical utility of PM measures, including the CAMPROMPT, in predicting aMCI found that the CAMPROMPT had the ability to discriminate aMCI from healthy individuals and that the time- and event-based scales of the CAMPROMPT were equally good in their discriminative ability.

3.2.3.2.5 National Adult Reading Test, Second Edition (NART; Nelson and Wilson, 1991)

The NART assessment requires the participant to read aloud 50 increasingly irregular words, i.e. those that do not follow the general rules of grapheme-phoneme correspondence and, thus, the correct pronunciation cannot be reached without previous knowledge of the word. However, participants are advised beforehand that they are not required to know all the words listed. The assessment takes a

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few minutes only to administer. The tester must, obviously, be familiar with the correct pronunciations of the words before administering the test, to score performance accurately. Scoring of the test provides a quick index of reading ability, thought to be relatively resistant to the effects of brain pathology and dementia (Nelson & McKenna, 1975). As such, it can provide an estimate of premorbid level of intellectual functioning in those with cognitive deterioration and, for the purpose of this study where significant deterioration is not suspected, an estimate of current levels of intellectual functioning.

In the original standardisation of the test, the NART was shown to have high reliability (Cronbach’s alpha = .93) and the authors concluded that the test had high validity due to the finding that dementia had a negligible effect on reading ability (Nelson & O’Connell, 1978). Normative data for the NART were provided based on a sample aged 20 – 70 years.

An estimate of premorbid intellectual functioning (IQ) is required to quantify an individual’s performance on the CAMPROMPT and NART scores were used as the index of IQ when the normative data for the CAMPROMPT were developed. This test was used, therefore, for accurate interpretation of performance on the CAMPROMPT.

3.2.3.2.6 Test Order

Questionnaires and objective cognitive tests were administered in the same sequence or order for all participants as follows; the PRMQ, HADS, socio-demographic, health and sleep-related questions were administered first, followed by administration of the cognitive tests commencing with the MMSE, then the Mini-Cog, GPCOG, CAMPROMPT and NART.

The rationale for ordering the administration of the subjective and objective cognitive tests in this manner was to ease participants into the testing situation. The subjective assessment was administered first and consisted of the administration of the sociodemographic questionnaire, followed by the PRMQ, since the subjective assessment was deemed to be less threatening to participants than the objective test assessment. Administration of the subjective assessment before objective assessments also allowed the examiner to build rapport through discussion about the aims of the study and clarification of, for example, sociodemographic and self-report memory questions. The order of administration of the objective tests themselves was based on perceived difficulty – combined with the need to avoid interference from one test to another. The MMSE, which is best at ruling out dementia, as opposed to detecting MCI, was expected to be the easiest for participants to complete successfully and was, therefore, administered first. The Mini-Cog and CGOCOG are both brief and both are recommended in key literature reviews for the detection of mild cognitive decline and were

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administered next. The CAMPROMPT can be considered cognitively demanding since it requires remembering PM tasks in the context of an ongoing activity and takes longer than the other objective tests to complete (25 minutes). It was decided to administer the CAMPROMPT after participants had already completed the brief assessment tools typically administered in clinical practice as a core goal of the study was to examine the relationships between self-reported and objective performance on widely used tests. Thus, these important data would be available even in cases where a participant did not complete the more demanding CAMPROMPT. Finally, in the context of this study, the NART score is required for the purpose of scoring the CAMPROMPT only. That fact, combined with the fact that people invariably commit a relatively high number of errors on the NART and may become upset by those errors, or have their confidence undermined by the errors, impacting on cognitive test performance, meant that this test was administered last.