A. de Jonghe

Effectiveness of melatonin treatment on circadian rhythm disturbances in dementia. Are there implications for delirium? : A systematic review

Circadian rhythm disturbances, like sundowning, are seen in dementia. Because the circadian rhythm is regulated by the biological clock, melatonin might be effective in the treatment of these disturbances. We systematically studied the effect of melatonin treatment in patients with dementia. In addition, we elaborate on the possible effects one might expect of melatonin treatment in patients with delirium, since dementia and delirium are strongly related. Moreover, some evidence exists that sundowning in patients with dementia and the alterations in the sleep/wake cycle, seen in patients with delirium both originate from circadian rhythm disturbances.

Development of an abbreviated version of the delirium motor subtyping scale (DMSS-4)

BACKGROUND Delirium is a common neuropsychiatric syndrome with considerable heterogeneity in clinical profile. Identification of clinical subtypes can allow for more targeted clinical and research efforts. We sought to develop a brief method for clinical subtyping in clinical and research settings. METHODS A multi-site database, including motor symptom assessments conducted in 487 patients from palliative care, adult and old age consultation-liaison psychiatry services was used to document motor activity disturbances as per the Delirium Motor Checklist (DMC). Latent class analysis (LCA) was used to identify the class structure underpinning DMC data and also items for a brief subtyping scale. The concordance of the abbreviated scale was then compared with the original Delirium Motor Subtype Scale (DMSS) in 375 patients having delirium as per the American Psychiatric Associations Diagnostic and Statistical Manual (4th edition) criteria. RESULTS Latent class analysis identified four classes that corresponded closely with the four recognized motor subtypes of delirium. Further, LCA of items (n = 15) that loaded >60% to the model identified four features that reliably identified the classes/subtypes, and these were combined as a brief motor subtyping scale (DMSS-4). There was good concordance for subtype attribution between the original DMSS and the DMSS-4 (κ = 0.63). CONCLUSIONS The DMSS-4 allows for rapid assessment of clinical subtypes in delirium and has high concordance with the longer and well-validated DMSS. More consistent clinical subtyping in delirium can facilitate better delirium management and more focused research effort.

A Longitudinal Study of Delirium Motor Subtypes in Elderly Hip Surgery Patients: Frequency and Determinants.

Introduction Delirium is a common neuropsychiatric syndrome with considerable heterogeneity that includes a variety of clinical (motor) subtypes. Because delirium is typically highly fluctuating, understanding the longitudinal stability of subtypes is crucial to evaluating their relevance to treatment and outcome. Aims to examine the changes (variability) in motor subtype profile in patients with delirium over serial assessment using the Delirium Motor Subtype Scale, and to investigate predictors of variability. Methods We studied motor subtype profile of patients with delirium assessed daily over a week in elderly patients undergoing hip fracture surgery. A Generalized Estimating Equations Model examined possible predictors of change in motor subtype status, including baseline variables and delirium course. Results We included 118 patients developing DSM-IV delirium after hip-surgery [mean age 87.0±6.5 years; range 65–102; 66% females]. At first assessment, hyperactive subtype was most common (49%), followed by hypoactive (31%) and mixed subtype (14%), with 6% of delirious patients not fulfilling criteria of any DMSS-defined motor subtype. Almost two-thirds (n=69) of these patients underwent at least one more assessment, and for these 45 (57%) remained stable in motor subtype over time, while the rest 34 (43%) underwent change. A range of baseline characteristics were not significant predictors of variability in subtype profile. Conclusions Motor subtype profile is typically stable for orthopaedic patients with delirium. Thus evidence from cross-sectional studies of motor subtypes can be applied to many patients with delirium. Further longitudinal studies can clarify the stability of motor subtypes across different clinical populations.

Polymorphisms in the Melatonin Receptor 1B Gene and the Risk of Delirium

Background/Aims: A disturbed sleep-wake rhythm cycle can be seen in delirium and as melatonin regulates this cycle via melatonin receptors, genetic variations in these receptors may contribute to susceptibility to delirium. The purpose of this study was to investigate whether genetic variants in the melatonin receptor 1B (MTNR1B) gene are associated with delirium. Methods: Elderly medical and hip surgery patients were included in the study. Five single-nucleotide polymorphisms (SNPs) were determined in the MTNR1B gene, i.e. rs18030962, rs3781638, rs10830963, rs156244 and rs4753426. Results: In total, 53% of 171 hip fracture patients and 33% of 699 medical patients were diagnosed with delirium. None of the polymorphisms were found to be associated with the occurrence of delirium. Conclusion: Future research could focus on sequencing this gene to look for other functional SNPs in relation to delirium.

Psychometric Evaluation of the DMSS-4 in a Cohort of Elderly Post-operative Hip Fracture Patients with Delirium.

Introduction Delirium is a common neuropsychiatric syndrome with considerable heterogeneity in clinical profile. Rapid reliable identification of clinical subtypes can allow for more targeted and research efforts. Aims The aims of this study are to evaluate the concurrent validity (agreement) and reliability (internal consistency) of DMSS-4 in a new cohort of delirious hospitalised patients. Methods We explored the concordance in attribution of motor subtypes between the DMSS-4 and the original DMSS (assessed cross-sectionally) and subtypes defined longitudinally using the Delirium Symptom Interview (DSI) method. Results We included 118 elderly patients developing DSM-IV delirium after hip-surgery [mean age 87.0±6.5 years; range 65–102; 66% females; 28 (23.7%) had no previous history of cognitive impairment]. Concordance was high for both the DMSS-4 and original DMSS (k=0.80), and for the DMSS-4 and DSI methods (k=0.82). The DMSS-4 also demonstrated high internal consistency (McDonalds omega = 0.78). The DMSS-11 and DMSS-4 had higher inclusion for motor subtypes than the DSI method. Conclusions The DMSS-4 provides an ultra-rapid means of identifying motor-defined clinical subtypes of delirium and is a reliable alternative to the more detailed and time-consuming original DMSS and DSI methods of subtype attribution. The DMSS-4 can be readily applied to further studies of causation, treatment and outcome in delirium.