OBJECTIVES: To evaluate the efficacy and safety of animal-assisted therapy for people with dementia.
SEARCH METHODS: We searched ALOIS: the Cochrane Dementia and Cognitive Improvement Group's Specialised Register on 5 September 2019. ALOIS contains records of clinical trials identified from monthly searches of major healthcare databases, trial registries, and grey literature sources. We also searched MEDLINE (OvidSP), Embase (OvidSP), PsycINFO (OvidSP), CINAHL (EBSCOhost), ISI Web of Science, ClinicalTrials.gov, and the WHO's trial registry portal.
SELECTION CRITERIA: We included randomised controlled trials (RCTs), cluster-randomised trials, and randomised cross-over trials that compared AAT versus no AAT, AAT using live animals versus alternatives such as robots or toys, or AAT versus any other active intervention.
DATA COLLECTION AND ANALYSIS: We extracted data using the standard methods of Cochrane Dementia. Two review authors independently assessed the eligibility and risk of bias of the retrieved records. We expressed our results using mean difference (MD), standardised mean difference (SMD), and risk ratio (RR) with their 95% confidence intervals (CIs) where appropriate.
MAIN RESULTS: We included nine RCTs from 10 reports. All nine studies were conducted in Europe and the US. Six studies were parallel-group, individually randomised RCTs; one was a randomised cross-over trial; and two were cluster-RCTs that were possibly related where randomisation took place at the level of the day care and nursing home. We identified two ongoing trials from trial registries. There were three comparisons: AAT versus no AAT (standard care or various non-animal-related activities), AAT using live animals versus robotic animals, and AAT using live animals versus the use of a soft animal toy. The studies evaluated 305 participants with dementia. One study used horses and the remainder used dogs as the therapy animal. The duration of the intervention ranged from six weeks to six months, and the therapy sessions lasted between 10 and 90 minutes each, with a frequency ranging from one session every two weeks to two sessions per week. There was a wide variety of instruments used to measure the outcomes. All studies were at high risk of performance bias and unclear risk of selection bias. Our certainty about the results for all major outcomes was very low to moderate. Comparing AAT versus no AAT, participants who received AAT may be slightly less depressed after the intervention (MD -2.87, 95% CI -5.24 to -0.50; 2 studies, 83 participants; low-certainty evidence), but they did not appear to have improved quality of life (MD 0.45, 95% CI -1.28 to 2.18; 3 studies, 164 participants; moderate-certainty evidence). There were no clear differences in all other major outcomes, including social functioning (MD -0.40, 95% CI -3.41 to 2.61; 1 study, 58 participants; low-certainty evidence), problematic behaviour (SMD -0.34, 95% CI -0.98 to 0.30; 3 studies, 142 participants; very-low-certainty evidence), agitation (SMD -0.39, 95% CI -0.89 to 0.10; 3 studies, 143 participants; very-low-certainty evidence), activities of daily living (MD 4.65, 95% CI -16.05 to 25.35; 1 study, 37 participants; low-certainty evidence), and self-care ability (MD 2.20, 95% CI -1.23 to 5.63; 1 study, 58 participants; low-certainty evidence). There were no data on adverse events. Comparing AAT using live animals versus robotic animals, one study (68 participants) found mixed effects on social function, with longer duration of physical contact but shorter duration of talking in participants who received AAT using live animals versus robotic animals (median: 93 seconds with live versus 28 seconds with robotic for physical contact; 164 seconds with live versus 206 seconds with robotic for talk directed at a person; 263 seconds with live versus 307 seconds with robotic for talk in total). Another study showed no clear differences between groups in behaviour measured using the Neuropsychiatric Inventory (MD -6.96, 95% CI -14.58 to 0.66; 78 participants; low-certainty evidence) or quality of life (MD -2.42, 95% CI -5.71 to 0.87; 78 participants; low-certainty evidence). There were no data on the other outcomes. Comparing AAT using live animals versus a soft toy cat, one study (64 participants) evaluated only social functioning, in the form of duration of contact and talking. The data were expressed as median and interquartile ranges. Duration of contact was slightly longer in participants in the AAT group and duration of talking slightly longer in those exposed to the toy cat. This was low-certainty evidence.
AUTHORS' CONCLUSIONS: We found low-certainty evidence that AAT may slightly reduce depressive symptoms in people with dementia. We found no clear evidence that AAT affects other outcomes in this population, with our certainty in the evidence ranging from very-low to moderate depending on the outcome. We found no evidence on safety or effects on the animals. Therefore, clear conclusions cannot yet be drawn about the overall benefits and risks of AAT in people with dementia. Further well-conducted RCTs are needed to improve the certainty of the evidence. In view of the difficulty in achieving blinding of participants and personnel in such trials, future RCTs should work on blinding outcome assessors, document allocation methods clearly, and include major patient-important outcomes such as affect, emotional and social functioning, quality of life, adverse events, and outcomes for animals.
MATERIALS AND METHODS: Whole genome sequencing of three strains of bifidobacteria was performed on the MiSeq platform (Illumina Inc., USA). The genomes were annotated using the Prokka v. 1.11 utility and RAST genomic server. The individual genetic determinants were searched using the ResFinder 3.2, PathogenFinder, PlasmidFinder, RAST, and Bagel 4 software. The antiviral activity of the strains against influenza A viruses was studied using MDCK cells (Madin-Darby canine kidney cells), the epidemic strain of influenza A/Lipetsk/1V/2018 (H1N1 pdm09) (EPI_ISL_332798), the highly pathogenic avian influenza virus A/common gull/Saratov/1676/2018 (H5N6) strain (EPI_ISL_336925), and neutral red vital dye.
RESULTS: The genomes of all studied strains contained determinants responsible for utilization of carbohydrates of plant origin; the genes of key enzymes for the synthesis of tryptophan and folic acid are present in the genomes of B. longum 379 and B. bifidum 791. A feature of the B. bifidum 791 genome is the presence of determinants responsible for the synthesis of thermostable type I bacteriocins - flavucin and lasso peptide. The B. bifidum 791 strain was found to show pronounced antiviral activity against both the strains of influenza A, the supernatant of which suppressed viral replication in vitro up to a dilution of 1:8, and the cells inhibited viral reproduction up to a concentration of 6·106 CFU/ml.
CONCLUSION: The analysis of complete genomes of B. longum 379, B. bifidum 1, and B. bifidum 791 showed features that determine their strain-specific properties, the findings on which were previously made empirically based on indirect signs. In the genomes of B. longum 379 and B. bifidum 791 strains, in contrast to B. bifidum 1 strain, key enzymes for the synthesis of tryptophan and folic acid were found. These substances have an impact on the human body in many ways, including having a thymoleptic effect (reducing emotional stress, irritability, anxiety, eliminating lethargy, apathy, melancholy, anxiety) and regulating cognitive activity. The presence of determinants responsible for the synthesis of thermostable type I bacteriocins in the genome of B. bifidum 791 strain determines its pronounced antiviral activity.