Reply
Year: 2009
Type: letter
Abstract: SIR—We would like to thank our colleagues for their interest and comments about our study [ 1 ]. Their communications [ 2, 3 ] reflect on our main questions, which are the most suitable clinical tool to use to assess delirium and the problems arising when assessing the most vulnerable population (i.e. elderly, medically ill with advanced cognitive impairment). In recent years, delirium research has focused on the development of several standardised instruments for assessments of delirant individuals [ 4, 5 ]. This has been a major advancement, as it has allowed operationalising criteria for delirium and improving its detection rates by using a systematic approach. Thus, the findings of Thomas and Oster [ 2 ] utilise this approach and stress the importance of the use of CAM in delirium diagnosis, similarly to our findings [ 1 ]. Although CAM has high sensitivity and specificity to identify delirium, data about how widely it is used in clinical setting are missing. Delirium is still, therefore, under-recognised and little is known about the proportion of all cases of delirium which are not recognised and what factors are associated with this poor recognition. Our study highlighted that a significant proportion of medically ill elderly patients were unable to be assessed with instruments heavily reliant on verbal production, such as MMSE, impairing the proper recognition of core symptoms as described by DSM or ICD definitions [ 6, 7 ]. This can be one of the reasons why delirium is under-recognised, especially the hypoactive subtype. Furthermore, the assessment tools currently recommended for the diagnosis of delirium (MMSE and clock drawing test; BGS guidelines, 8) do not address directly the two core clinical symptoms of delirium, of impaired concentration/attention and altered level of consciousness. This is further confirmed in both studies using MMSE [ 1 ] and clock drawing test [ 3 ]. Although the clock drawing test can be an interesting alternative to MMSE to assess cognitive function (due to it being a brief tool and less dependent on language), the results presented by [ 3 ] show that 28% of their sample were unable to complete the test, similar to our results (24.2%; 1). In addition, certain higher cognitive functions (e.g. visuospatial disorientation, problems planning and praxis) appear to be highly sensitive accompanist of delirium, as confirmed in both our study (via lower MMSE scores, 1) and that of [ 3 ]. Although the authors do not mention the percentages of incomplete/failed clock drawing tests in their much larger study, especially for the delirium group, the data are suggestive of the delirium patients, all failing to complete the clock drawing test successfully. The discrepancy in the final outcome of the follow-up for the delirium subgroups [ 3 ] may well be attributable to different types of delirium or the polymorbidity. This further supports the need for more extensive research on the whole spectrum of the delirium syndrome, rather than concentrating on small analysed groups. This approach may have the potential to identify more sensitive and specific assessment tools needed to differentiate between the chronic and ‘acute on chronic’ confusion (dementia and delirium, respectively) in the medically ill elderly for delirium, and also reflect on putative distinctive profiles of delirium subtypes. Only in this way, we may be able to address and potentially even define distinct types of clinical delirium assessments. This approach was beyond the scope of the design of our study that aimed only to address the applicability of the BGS delirium guidelines [ 8 ] in a clinical setting. Research on delirium should look for alternative tools that could be useful to assess core features of delirium, such as inattention and disturbance of consciousness, which are not easily captured by the instruments currently available and require a better operationalisation. The final aim would be to have a highly sensitive and specific test that will aid the delirium diagnosis. However, the currently putative markers for delirium (e.g. elevated CRP, lower albumin levels, elevation in inflammatory markers, protease inhibitors etc.; reviewed in [ 9 ]) need to be considered with caution in the light of the known age- and medically altered levels, and thus may not have the necessary sensitivity and specificity to discriminate delirium. This is also valid for the brain electroencephalogram (EEG) changes, since the general slowing of the brain activity is associated with the dementia syndrome, too. Better understanding of the delirium pathophysiology and its molecular substrates will allow the development of complementary laboratory tools, which can help not only in the early diagnosis and differentiating between delirium and dementia, but also in monitoring and prognosis of the delirium syndrome.
Source: Age and Ageing
Authors: E. B. Mukaetova-Ladinska, J. Cerejeira, C. Yates, N. Stanley, R. Jay
Institution: Newcastle University
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W4246490967