Measuring physiological parameters of stress in horses during groundwork, for example when involved in equine-assisted interventions, is important to gain insight into the stress levels of the horses. Heart rate and heart rate variability can be used as physiological indicators of stress in horses. Heart rate monitors could be easily incorporated into practice, as they are not expensive and easy to use. However, it is questionable whether heart rate monitors present accurate heart rate variability results in exercising horses, similar to electrocardiograms. The aim of this study was to determine the accuracy of heart rate monitors for the assessment of heart rate variability in horses during groundwork exercise. Simultaneous telemetric electrocardiograms (Televet) and heart rate monitor (Polar H10 transmitter and M430 receiver, Hylofit electrodes) recordings were performed on 28 horses (15 mares and 13 geldings). Results indicate that the heart rate monitor accurately determined heart rate and time-domain heart rate variability parameters when compared to electrocardiograms during both baseline and groundwork conditions. As expected, heart rate significantly increased and the heart rate variability significantly decreased during groundwork compared to baseline conditions. This indicates that the heart rate monitor can be used to accurately determine heart rate variability during groundwork.

Fear and anxiety disorders are prevalent in dogs. These disorders are not adequately resolved by current interventions, which urges exploration of additional interventions. In humans, fear and anxiety disorders such as post-traumatic stress disorder (PTSD), are effectively treated by Eye Movement Desensitization and Reprocessing (EMDR). EMDR is a non-invasive and non-pharmacological intervention involving bilateral sensory stimulation while memorizing the traumatic event, resulting in decreased emotionality of the memory. We argue EMDR might be applied as an intervention for fear and anxiety disorders in dogs, adding to the currently available interventions for the field of Clinical Ethology. Particularly nonverbal EMDR protocols used in preverbal children can be applied and the setup can be adapted for dogs. Future research should focus on the development of nonverbal EMDR protocols including proper controls, and on clinical effectiveness of such EMDR protocols for dogs. Apart from behavioural measures, psychophysiological variables should be incorporated as well.

Introduction: Military veterans are at an elevated risk of developing posttraumatic stress disorder (PTSD), while first-line trauma-focused treatments are less effective in this population. This highlights the need for novel, evidence-based complementary interventions for military veterans with treatment-resistant PTSD. Although equine-assisted interventions (EAIs) are increasingly popular and appear promising, many studies suffer from methodological issues. Therefore, further research incorporating both psychometric and physiological parameters is warranted. Methods: Nine consecutive groups of eight veterans ( n = 72; 58 men and 14 women) participated in this study. Due to a dropout rate of 8.33% and the exclusion of 11.11% of participants for missing more than two sessions, 58 veterans were included in the dataset. All participants had a prior PTSD diagnosis and/or a score >31 on the PTSD Checklist for DSM-5 (PCL-5) questionnaire at intake and had previous evidence-based treatment but continued to experience symptoms. The program consisted of 12 weekly non-trauma-focused group sessions and one follow-up session (week 24), all lasting from 10:00 to 15:00. Measurements were performed during baseline conditions (B), a 20-min free activity (F) focused on relaxation and social affiliative contact with the horse, and a 30-min directed activity (D) involving caretaking, groundwork, and riding. Results: Psychometric questionnaires demonstrated a significant decrease in PTSD symptoms (PCL-5), an improvement in sleep quality (Pittsburgh Sleep Quality Index [PSQI]), and an improvement in quality of life (EuroQol 5-Dimension 5-Level questionnaire [EQ-5D-5L]), with effects persisting at least until the 3-month follow-up session. No significant differences in heart rate (HR) or heart rate variability (HRV) were observed between pre- and post-intervention. However, during EAI sessions, patterns consistent with physiological adaptation were observed, as HR decreased and HRV increased after the first week during free interactions with the horse. Discussion: In conclusion, the EAI program was associated with long-term effects on PTSD, sleep quality, and quality of life in veterans with treatment-resistant PTSD. No structural changes in physiological parameters were found, only evidence for successful adaptation to acute stress during EAI sessions. We hypothesize that adaptation to physiological arousal during acute stress may represent a possible working mechanism of EAI.

Introduction: Veterans are at greater risk of developing post-traumatic stress disorder (PTSD) and show a poorer response to first-line treatments than civilians. Although equine-assisted interventions (EAIs) represent a promising alternative for military veterans,the underlying mechanisms remain uncertain, and their effectiveness across different PTSD symptom clusters has yet to be established. This study examined the effects of a non-trauma-focused EAI on specific PTSD symptoms in treatment-resistant military veterans. Material and methods: Participants in the intervention were military veterans diagnosed with PTSD by their psychological or psychiatric referrer, all of whom had received previous first-line trauma treatment prior to study enrolment. The dataset included 43 veterans who completed the Dutch PTSD Checklist (PCL) for the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) at week 1 and week 24, and who met the PTSD criteria at baseline according to the PCL-5. The EAI was a 12-week group program during which veterans had individual interactions with a horse once a week from 10:00 to 15:00. PTSD symptoms were assessed using the PCL-5 at weeks 1, 4, 8, 12, 24, and 52. Results: A linear mixed model showed that scores for all four PTSD symptom clusters significantly improved over the course of the program. Cluster B (intrusion) and cluster C (avoidance) decreased even further after termination of the program at week 12, demonstrating additional long-term effects. Cluster D (negative changes in cognition and mood) and Cluster E (arousal and reactivity) remained low but did not decrease further after week 12. In addition, the reliable change index (RCI) and clinically significant change (CSC) were calculated, resulting in suboptimal (51.2%; n = 22), improved (23.3%; n = 10), and recovered (25.6%; n = 11) treatment-outcome groups. Discussion: This indicates that 25.6% achieved both reliable and clinically meaning full symptom reduction in response to the program, and 23.3% demonstrated statistically reliable but not fully clinically significant improvement, while 51.2% did not show any improvement. Although responsiveness over time differed, all PTSD symptom clusters improved significantly during the EAI program in treatment-resistant military veterans. Suggesting that further research with controlled study designs on the effectiveness of EAI as an adjunctive intervention to TFT for military veterans with residuals symptoms would be of value.