Background: The involvement of retina and its vasculature has been recently described in Alzheimer’s disease (AD). However, none of the previous works have yet investigated the choroid in vivo. Objective: Spectral domain optical coherence tomography (SD-OCT) and enhanced depth imaging (EDI) technique is non-invasively used to assess choroidal thickness in patients with AD and to determine whether the peripapillary retinal nerve fiber layer (RNFL) and central retinal thickness are reduced compared to normal subjects. Methods: Forty-two eyes of 21 patients (mean age, 73.1 ± 6.9 years) with a diagnosis of mild to moderate AD and 42 eyes of 21 age-matched control subjects (mean age, 70.3 ± 7.3 years) were included in this prospective, cross-sectional study. All the subjects underwent neuropsychological (MMSE, ADAS-Cog, and CDR) and ophthalmological evaluation. The SD-OCT images of the choroid were obtained by EDI modality. Choroidal thickness was assessed by manual measurement. The following parameters, measured automatically by the OCT software, were also analyzed for each eye: 1-mm central subfield (CSF) retinal thickness, peripapillary RNFL thickness. Results: Choroidal thickness was significantly thinner in AD than in control eyes (p < 0.05). No difference in CSF retinal thickness was found between groups (p > 0.05). Mean peripapillary RNFL thickness in all four quadrants was similar between groups (p > 0.05). OCT measurements were not correlated with any of the tested psychometric parameters (p > 0.05). Conclusion: Compared with healthy subjects, patients with AD showed a significant reduction in choroidal thickness. Choroidal thinning may represent an adjunctive biomarker for the diagnosis and follow-up of this disease.

Sundowning means the emergence or worsening of neuropsychiatric symptoms (NPS) in the late afternoon or early evening. This syndrome has been recognized since a long time in the field of dementing illnesses and is well known among most of healthcare providers involved in the assistance of people with dementia. Indeed, it represents a common manifestation among persons with dementia, and is associated with several adverse outcomes (such as institutionalization, faster cognitive worsening, and greater caregiver burden). Its occurrence and phenotypic characteristics may be influenced by diverse neurobiological, psychosocial, and environmental determinants. Moreover, it may pose diagnostic challenges in relation to other common causes of behavioral disruptions. Beside these considerations, this phenomenon has so far drawn limited clinical and scientific interest compared to other specific NPS occurring in dementias, as indicated by the lack of commonly agreed definitions, specific screening/assessment tools, and robust estimates on its prevalence. Accordingly, no randomized controlled trial (RCT) specifically investigating the effectiveness of pharmacological and non-pharmacological strategies in managing this condition among demented patients has been yet conducted. In the present narrative review we present and discuss available evidence concerning sundowning occurring in people with dementia. A special focus is given to its definitions, pathophysiological determinants, and clinical relevance, as well as to the clinical and therapeutic approaches required for its management in the daily practice.

See Caravaggio and Graff-Guerrero (doi: 10.1093/awx023 ) for a scientific commentary on this article. Antipsychotic drugs, originally developed to treat schizophrenia, are used to treat psychosis, agitation and aggression in Alzheimer’s disease. In the absence of dopamine D2/3 receptor occupancy data to inform antipsychotic prescribing for psychosis in Alzheimer’s disease, the mechanisms underpinning antipsychotic efficacy and side effects are poorly understood. This study used a population approach to investigate the relationship between amisulpride blood concentration and central D2/3 occupancy in older people with Alzheimer’s disease by combining: (i) pharmacokinetic data (280 venous samples) from a phase I single (50 mg) dose study in healthy older people (n = 20, 65–79 years); (ii) pharmacokinetic, ¹⁸F-fallypride D2/3 receptor imaging and clinical outcome data on patients with Alzheimer’s disease who were prescribed amisulpride (25–75 mg daily) to treat psychosis as part of an open study (n = 28; 69–92 years; 41 blood samples, five pretreatment scans, 19 post-treatment scans); and (iii) ¹⁸F-fallypride imaging of an antipsychotic free Alzheimer’s disease control group (n = 10, 78–92 years), to provide additional pretreatment data. Non-linear mixed effects modelling was used to describe pharmacokinetic-occupancy curves in caudate, putamen and thalamus. Model outputs were used to estimate threshold steady state blood concentration and occupancy required to elicit a clinically relevant response (>25% reduction in scores on delusions, hallucinations and agitation domains of the Neuropsychiatric Inventory) and extrapyramidal side effects (Simpson Angus Scale scores > 3). Average steady state blood levels were low (71 ± 30 ng/ml), and associated with high D2/3 occupancies (65 ± 8%, caudate; 67 ± 11%, thalamus; 52 ± 11%, putamen). Antipsychotic clinical response occurred at a threshold concentration of 20 ng/ml and D2/3 occupancies of 43% (caudate), 25% (putamen), 43% (thalamus). Extrapyramidal side effects (n = 7) emerged at a threshold concentration of 60 ng/ml, and D2/3 occupancies of 61% (caudate), 49% (putamen) and 69% (thalamus). This study has established that, as in schizophrenia, there is a therapeutic window of D2/3 receptor occupancy for optimal treatment of psychosis in Alzheimer’s disease. We have also shown that occupancies within and beyond this window are achieved at very low amisulpride doses in Alzheimer’s disease due to higher than anticipated occupancies for a given blood drug concentration. Our findings support a central pharmacokinetic contribution to antipsychotic sensitivity in Alzheimer’s disease and implicate the blood-brain barrier, which controls central drug access. Whether high D2/3 receptor occupancies are primarily accounted for by age- or disease-specific blood–brain barrier disruption is unclear, and this is an important future area of future investigation, as it has implications beyond antipsychotic prescribing.

Introduction: To compare the 12-month choroidal thickness (CT) change between Alzheimer disease (AD) patients and normal subjects. Methods: In this prospective, observational study, 39 patients with a diagnosis of mild to moderate AD and 39 age-matched control subjects were included. All the subjects underwent neuropsychological (Mini Mental State Examination, Alzheimer disease Assessment Scale-Cognitive Subscale, and the Clinical Dementia Rating Scale) and ophthalmological evaluation, including spectral domain optical coherence tomography, at baseline and after 12 months. CT was measured manually using the caliper tool of the optical coherence tomography device. Results: After 12 months, AD patients had a greater reduction of CT than controls (P≤0.05, adjusted for baseline CT, age, sex, axial length, and smoking). Discussion: CT in patients with AD showed a rate of thinning greater than what could be expected during the natural course of aging.

Objectives: To perform a meta-analysis of clinical studies on the differences in treatment or research decision-making capacity among patients with Mild Cognitive Impairment (MCI), Alzheimer’s disease (AD), and healthy comparisons (HCs). Design: A systematic search was conducted on Medline/Pubmed, CINAHL, PsycINFO, Web of Science, and Scopus. Standardized mean differences and random-effects model were used in all cases. Setting: The United States, France, Japan, and China. Participants: Four hundred and ten patients with MCI, 149 with AD, and 368 HCs were included. Measurements: The studies we included in the analysis assessed decisional capacity to consent by the MacArthur Competence Assessment Tool for Treatment (MAcCAT-T), MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR), Capacity to Consent to Treatment Instrument (CCTI), and University of California Brief Assessment of Capacity to Consent (UBACC). Results: We identified 109 potentially eligible studies from 1672 records, and 7 papers were included in the meta-analysis. The meta-analysis showed that there was significant impairment in a decision-making capacity in MCI patients compared to the HCs group in terms of Understanding (SMD = −1.04, 95% CI: −1.31 to −0.77, P < 0.001; I2 = 52%, P = 0.07), Appreciation (SMD = −0.51, 95% CI: −0.66 to −0.36, P < 0.001; I2 = 0%, P = 0.97), and Reasoning (SMD = −0.62, 95% CI: −0.77, −0.47, P < 0.001; I2=0%, P =0.46). MCI patients scored significantly higher in Understanding (SMD = 1.50, 95% CI: 0.91, 2.09, P = 0.01, I2 = 78%, P = 0.00001) compared to patients affected by AD. Conclusions: Patients affected by MCI are at higher risk of impaired capacity to consent to treatment and research compared to HCs, despite being at lower risk compared to patients affected by AD. Clinicians and researchers need to carefully evaluate decisional capacity in MCI patients providing informed consent.