What The Presence Of Animals Do To The Brain

Introduction

Patients in a minimally witting state (MCS) demand early treatment to facilitate physical as well as cognitive recovery and to reduce the hazard of long-term inability and institutionalization (Seel et al., 2013). Early onset stimulation in an enriching surroundings as an integrative part of early rehabilitation programmes has emerged every bit an effective treatment for encouraging MCS patients' recovery (La Gattuta et al., 2018; Pistarini & Maggioni, 2018). A central component of this approach is an individualized and integral activation of the patient as well as the promotion of inner perception and emotional sensation (Zieger, 2002). Biographical or emotionally loaded stimuli lead to increased consciousness as well every bit an increase in vegetative responses and psychomotor reactions in MCS patients (Perrin et al., 2015). Animals are emotionally relevant stimuli for most people (Zieger, 2016) and creature-assisted therapy (AAT) is increasingly seen as an important component in early on rehabilitation of patients with severe disorders of consciousness (Blankenburg et al., 2011; Böttger, 2008; Janssen & Zieger, 2009).

Although AAT is increasingly used with MCS patients in neurorehabilitation clinics, there is picayune inquiry on its effects on the primal nervous system. A single-case report documents a young woman who, after being in a persistent vegetative land for 5 years without signs of recovery, showed increased vegetative, emotional reactions and goal-directed motor behaviour towards a therapy dog (Bardl et al., 2013). Like furnishings were noted in a report by Zieger (2011) who investigated the effects of dog-assisted therapy sessions with 13 patients with severe disorders of consciousness. The authors reported significant increases in the patients' positive facial expressions, visual exploration and spontaneous, goal-directed orientation towards the dog during the AAT session in comparison to sessions when the domestic dog was non present. A get-go controlled report found more behavioural reactions and increased physiological arousal during AAT compared to control sessions in MCS patients, indicating that the presence of an animal might increase consciousness (Hediger et al., 2019).

These results advise positive effects of AAT on patients with severe disorders of consciousness but further piece of work is needed to evaluate AAT as a handling approach.

Since awareness might not exist fully reflected by but behavioural reactions (Bruno et al., 2011; Naro & Calabro, 2020) or is but shown by very subtle signs such as changes in muscular tone for example, information technology is of import to investigate neurophysiological processes in order to better understand effects of an intervention. Nosotros used functional about infrared spectroscopy (fNIRS) to measure out the influence of animals on brain activity of MCS patients. fNIRS provides an constructive measure of neural activeness reflecting e.g., mental workload or emotional processing (Hirshfield et al., 2015; Minati et al., 2009; Scheunemann et al., 2019) and has also been used in MCS patients (Kempny et al., 2016). Since we were interested in attention and emotional processing, nosotros measured prefrontal activity. For a better estimation of the results in MCS patients, we included healthy subjects as control group.

This airplane pilot study investigates prefrontal hemodynamic responses of MCS patients and healthy command subjects in the presence and interaction with a live animal compared to a mechanical toy animal.

Materials and methods

Participants

2 patients in a minimally witting state, mean age of 37.0 years (SD= 1.0) participated in this study. Patients were in stationary neurorehabilitation at REHAB Basel and diagnosed with acquired encephalon injury with non-traumatic causes (Due north= 2). In order to participate, patients needed a MCS diagnosis on the basis of the original JFK Coma Recovery Scale (Giacino et al., 1991; Giacino et al., 2002) (CRS) and following the Aspen diagnostic criteria (Kempny et al., 2016). Patients were assessed by physicians non involved in the study. Exclusion criteria were personal or medical contraindications such as phobias or allergies to animals. According to the dispensary's hygiene concept, ane patient with a minor bacterial infection had to article of clothing sterile prophylactic gloves during the contact with the live animal. To control for specific effects in MCS patients, nosotros included ii salubrious adults, hateful historic period of 50.0 years (SD= 4.5). Good for you control subjects had no allergies or fear of animals and needed to be >xviii years. The number of participants was chosen co-ordinate to the pilot graphic symbol of the written report. Informed consent was obtained from the legal representative of each patient, while healthy participants provided their informed consent in writing prior to their participation. The human-related protocols were canonical by the Human Ideals Commission for Northwest and Central Switzerland (EKNZ) and the animal-related protocols were approved by the Veterinary Office of the Canton Basel-Stadt, Switzerland. Homo-beast interaction was performed according to the guidelines of the International Clan of Homo Animal Interaction Organizations (IAHIAO) (2018). No adverse incidents occurred and no session had to be terminated. After participating in the written report, all MCS patients had the possibility to go along with AAT as part of their rehabilitation programme.

Study design and procedure

The study had a controlled within-discipline design with repeated measurements. Over two weeks, each participant was assigned to a total of 6 standardized sessions. Three were experimental sessions with a live fauna present and three were control sessions with a mechanical toy beast nowadays.

MCS patients were either seated in a wheelchair or mobilized in bed in an upright position while the healthy control subjects were seated on a chair. Before the start of a session, both patients and healthy control participants were informed about the process and shown the fNIRS device. Later on plumbing equipment the fNIRS cap on the participant´s head, all sources and detectors were adjusted until the signal quality was acceptable.

Each session consisted of five phases in a defined order, each lasting lx s. In the get-go phase (i: baseline), participants looked at the white wall in front of them and the live beast or mechanical toy animal was kept out of sight. During the 2d phase (2: watching), a table, on which the live or mechanical toy beast was placed, was moved into sight but kept out-of-reach. The participants watched the live or mechanical toy animal. During the third stage (3: passive contact), the alive or mechanical toy creature was placed on the participant´south lap but it was not touched by the participant. During the fourth phase (iv: agile contact), the participants stroked the live or mechanical toy fauna. Healthy participants stroked the fauna self-initiated while patients were assisted. During straight contact with the live fauna, the animal was closely observed by the creature attendant and the patient was monitored by a staff member to enable intervention if necessary. During the fifth and terminal stage (five: neutral), the live or mechanical toy animal was placed out of sight and participants looked at the wall in front of them as they did in stage 1. In total, each session lasted for about fifteen min.

Functional virtually infrared spectroscopy (fNIRS)

Brain activity was measured with a portable functional NIRS device (NIRSport, NIRx Medizintechnik GmbH, Berlin, Germany). The device consisted of a cap with 7 sources and eight detectors arranged and then that fifteen-channels covered the prefrontal expanse of the head. The sources illuminated the cranial cavity using about-infrared light just beyond the visible cherry region of the electromagnetic spectrum. The light had a wavelength of 760 and 850 nm. This enables measuring the changes in the concentration of cerebral oxygenated (O₂Hb in µM), deoxygenated (HHb in µM), total hemoglobin (tHb in µM) and tissue oxygen saturation of hemoglobin (StO_two in %) of the frontal cortex. The tHb reflects changes in the cerebral blood flow and the StO₂ the balance between the cerebral metabolic rate of oxygen and blood flow. Source-detector distance was kept constant at two.five cm and sample charge per unit was viii.93 Hz. Measurements were recorded using NIRx acquisition software (NIRStar, Ver. 14.one, NIRx Medizintechnik GmBH, Berlin, Federal republic of germany). Markers were set to identify the start and end of each stage during all sessions: (1) baseline, (2) watching, (iii) passive contact, (four) active contact, and (5) neutral. All signals were recorded on a laptop PC and stored on its hard drive for subsequent assay. The raw information were transformed, normalized and bandpass filtered (0.01 Hz Low cutoff and High cutoff 0.2 Hz, Roll off width (%): 15, fifteen) with NIRSLab software.

Live creature

We included guinea pigs and a modest dog in the experimental sessions with participants. The aforementioned animal was always nowadays for a specific participant for all sessions according to their preference. All animals were trained to interact with patients with severe disorders of consciousness. To ensure security and comfort, participants were accompanied past a trained member of the study squad during the entire session. This person closely observed the patients for any signs of fear or discomfort. If whatever were observed, the session would have been terminated immediately. Animals were brought into the room before the start of the session, allowing them to acclimatize. The guinea pigs were placed on an enclosure-similar table. A house also as their transport box allowed them to retreat earlier and after the session. The animals were placed on the participants lap on a pet bed during the phases "passive contact" and "active contact." During all session, the brute's safety was ensured by the presence of an beast attendant of the clinic and the therapy dog was always accompanied by its owner.

Mechanical toy beast

A battery-driven mechanical toy rabbit (Hamleys Movers & Shakers, London, UK) served as the command stimulus. The toy rabbit had synthetic fur, measured 17 × 12 × nineteen cm, hopped, moved its ears and simultaneously emitted a squeaky audio.

Data analysis

Information of any fNIRS channels that did not tape a skilful bespeak were excluded from analysis. Last assay was performed using the data of half-dozen channels that showed a consistent, clear point in all participants. For each aqueduct, the hateful concentration of O_iiHb, HHb and tHb was calculated, and the values were saved in an ASCII file. These values were subsequently used to derive the median and per centum of hemoglobin concentrations relative to the maximum of each private. Data were and so averaged for all corresponding phases over the three AAT sessions and the iii control sessions. The baseline was gained by calculating the mean average of the baseline stage and the neutral stage for each participant over all half-dozen sessions. Mean O_twoHb and HHb changes were calculated for each participant and each phase. Data were descriptively analysed.

Results

Information of one female and ane male patient, total of five sessions each, were analysed. I patient interacted with a dog and one patient with guinea pigs. Data from one female and one male control participant, total of vi sessions each, held with either a canis familiaris or the guinea pigs, were included. Patients were younger, with a mean age of 37 years (SD= 1.0), compared to the salubrious control participants, with a mean age of 50 years (SD= 4.5). According to the CRS, both patients had auditory reactions such as opening eyes and turning the head towards a stimulus while patient one showed only occasional gaze at visual stimuli by chance only patient two followed objects and persons with her gaze at study start. Patient i reacted to passive tactile stimuli while patient 2 showed spontaneous and targeted movements with her hands (meet Table one).

Table 1. Sample characteristics.

Neural action and hemodynamic response

The individual hemodynamic response of every participant is shown in Effigy 1. Both MCS patients showed an increased hemodynamic response, resulting in an increase in O_twoHb, as the intensity of the stimulus increased. The signal was weakest during the baseline and when watching the live and toy animal, while it was strongest during active contact when either the live or the mechanical toy animal was stroked. This clear blueprint could not exist observed in healthy control subjects.

Figure 1. Hateful O_twoHb and HHb concentrations for each phase and each participant.

During agile contact, three of 4 participants showed a larger hemodynamic response when stroking the live brute compared to stroking the mechanical toy fauna. One patient showed a larger hemodynamic response while stroking the mechanical toy compared to the alive brute. During passive contact, iii of four participants showed larger hemodynamic responses with the mechanical toy compared to the live animal. 1 healthy control subject reacted with a larger hemodynamic response when the alive animal was placed on the lap compared to the mechanical toy animal, representing the maximum response of this person over all sessions (see Figure 1).

Patterns of hemodynamic response

When comparing the signal in O_twoHb and HHb, nosotros observed three different hemodynamic patterns. The showtime follows the typical fNIRS response, with an increase in oxygenated hemoglobin and a subtract in deoxygenated hemoglobin (Tachtsidis & Scholkmann, 2016). This blueprint was observed in all participants but more than oftentimes in the two good for you control subjects than in the ii MCS patients. Second, an inverted fNIRS response was observed, in which O_iiHb decreased and HHb increased. In all iv participants, this pattern occurred reliably simply during active contact, when either the live or mechanical toy animal was stroked. Additionally, i MCS patient besides showed this inverted signal during passive contact with the mechanical toy animate being. Third, a blueprint with almost similar O_twoHb and HHb signals occurred randomly during some phases in the MCS patients.

Discussion

Data assay revealed clear hemodynamic responses in the two MCS patients and the two healthy control subjects in response to different levels of interaction with the live and the mechanical toy fauna. First, we constitute a consistent blueprint of increased hemodynamic response of O₂Hb with increasing stimulus interaction in both MCS patients. Second, nosotros found differences in the responses to the experimental condition with a live animal present and the control status with a mechanical toy animal present. During active contact, three of four participants showed a higher hemodynamic response when stroking the live beast compared to stroking the mechanical toy. Conversely, during passive contact, three of four participants showed larger hemodynamic responses with the mechanical toy compared to the live animal. Third, we consistently found an inverted betoken with higher HHb than O₂Hb concentrations in all four participants when either the live or mechanical toy animal was stroked. In all other phases, the signal matched the expected neural activation response typically measured using fNIRS with an increment in O_iiHb and a decrease in HHb.

The fact that we found articulate hemodynamic responses in both the MCS patients and the healthy control subjects in response to different activities leads to the assumption that fNIRS is a valid tool to investigate effects of beast contact in MCS patients. However, we found differences betwixt MCS patients and good for you controls, with MCS patients showing a much more consequent response in relation to different levels of stimulus intensity. MCS patients reacted to tactile stimulation during passive contact and showed the largest reaction during active contact with the live or toy brute, when interaction was maximal. These results are in line with previous inquiry showing that patients with astringent brain injuries react better to tactile stimulation (Keller et al., 2007) and to multiple stimulation compared to singular stimulation (Maegele et al., 2005; Megha et al., 2013).

The observed different responses to the presence of a live or mechanical toy animal atomic number 82 usa to assume that a alive animal elicits more distinct psychological and neuronal processes than a mechanical toy animal. Nosotros propose that the reactions to the mechanical toy brute represent attention processing, while the active contact with the live animal includes an additional emotional component. This assumption is in line with previous enquiry documenting that interacting with animals tin lead to increased positive emotions beingness reflected on a neurophysiological level. In children, activation of the emotional prefrontal area was detected via fNIRS while they were experiencing AAT after having stressful surgery (Calcaterra et al., 2015). Patients with mood disorders showed increases in oxygenated hemoglobin in the prefrontal cortex during interaction with a dog compared to performing a exact fluency chore (Aoki et al., 2012). Watching positive man-animal interactions led to larger prefrontal encephalon activation in good for you participants than watching aggressive interactions (Vanutelli & Balconi, 2015).

In our report, only one patient showed a stronger response to touching the mechanical toy beast compared to touching the live fauna. This was a patient who had to clothing sterile rubber gloves for hygienic reasons. The live animal normally did not motility, while the mechanical toy animal was moving. Therefore, the mechanical toy animal might take had a stronger sensory input considering this patient could feel movements through the glove just the sensation of the soft fur in both the living and the toy fauna was missing. This indicates that direct skin contact is of import when interacting with an creature. Moreover, we propose that the active interaction is an important component. In all 4 participants, the hemodynamic response changes from a typical fNIRS reaction into an inverted reaction when having active contact with the animal. The subtract in O₂Hb is usually associated with decreased neuronal activeness (Tachtsidis & Scholkmann, 2016). Notwithstanding, it could as well exist that the number of activated neurons increased during the active contact, (Marcar & Loenneker, 2004) consequently leading to a higher oxygen consumption, and therefore however representing a higher prefrontal activation of the participants. Another caption for the inverted bespeak during agile contact could be the relaxing and stress reducing effect that is known to be elicited by animals (Ein et al., 2018). The decrease in O₂Hb, therefore, would reflect a decrease in brain activity due to relaxation. Previous PET imaging and fNIRS studies have shown that relaxing and stress reducing effects of animals can be reflected by neurophysiological processes in the encephalon (Aoki et al., 2012; Sugawara et al., 2015).

Limitations, strengths and hereafter Directions

The pilot grapheme of this study, with its modest sample size, does non let for generalization of the results but rather provides hypotheses almost effects and mechanisms for future research. Another limitation is that participants could non be blinded for the 2 conditions, considering the presence of the live fauna was obvious. In our pattern, we cannot distinguish between the patient'south reactions to the touch of the therapist or the alive or toy animal. It might be possible that the increased reaction from the passive contact to the active contact with the animal as well includes a reaction to existence touched past the therapist's hand to guide the patient's movements. This is a method to facilitate movements co-ordinate to the Affolter concept (Affolter et al., 2000). However, in the Affolter concept, it is idea that bear upon of the therapist while guiding a patient'due south easily in a correct way will lose its salience considering there is little change in sensory input between the therapist'southward paw and the patient'southward hand, while there is clear change in sensory input between the patient's hand and an external stimulus such as the animal'southward fur (either alive or toy). It might exist that some of the reactions that the patients showed, even so, are reactions to the touch on of the therapist. But since stroking was facilitated in both conditions, the clear difference betwixt the live and the toy fauna can be seen as an effect of straight physical contact with the brute. Moreover, we practice not know what characteristics of the presented stimuli (live or toy animal) such as motility, sound, fur, warmth etc. lead to the patients' reactions. To increase knowledge virtually what characteristics of a stimulus assistance increase awareness and arousal in MCS patients should be investigated in farther studies by systematically controlling for these aspects. fNIRS data has to be interpreted with circumspection since it not simply reflects cerebral hemodynamic changes but as well extracerebral hemodynamic changes. However, the data brandish a clear difference between the single phases of the session in all participants, and the reaction patterns were very comparable. This implies that, likewise all limitations, neurovascular responses to animal presence and contact can exist measured in MCS patients using fNIRS. All participants were measured repeatedly in both conditions. This within-bailiwick design made information technology possible to command for the different medical weather of the patients.

Further research should investigate the effects of animals with more than patients and healthy controls and with longer lasting phases of agile and passive animal contact. A more than comparable and less distracting control object should be called to command for the actual effect of a live beast, and we recommend combining different physiological parameters with behaviour based evaluations. Hereafter studies should as well include systematic behavioural analysis to further investigate clinical relevance of these findings. In our study, the patients showed articulate behavioural reactions, simply we did not analyse it systematically via video coding. 1 of the patients showed facial expressions that we interpreted equally a possible smiling indicating a positive emotional reaction while he touched the live beast. No such facial expression was observed before he touched the live brute. Moreover, he opened his optics, which were closed for most of the session, when he touched the animal and kept them open while stroking it. The other patient reacted with smiling and turning her caput during passive as well as active contact with the live and the mechanical toy brute. Again, this behaviour was not observed before the contact with the animal and we interpret these behaviours as a sign of an emotional reaction. These observations are in line with the results of a study indicating that patients in MCS evidence more behavioural reactions during AAT compared to control sessions (Hediger et al., 2019) and refer to possible clinical awarding of AAT in patients with MCS.

Decision

Our results prove that MCS patients testify increased neuronal reactions with increasing stimulus interaction. This indicates that stimuli should be presented in a way that the patients can actively interact with them and perceive them with multiple senses. Our data imply that mechanical toy animals might be a useful instrument in neurorehabilitation treatments to activate attending processes in MCS patients. Nonetheless, the results advise that animals can lead to an even college activation based on emotional processes. This emotional component is central in integral rehabilitation (Zieger, 2002). The integration of animals in neurorehabilitation of patients in a minimally conscious country could therefore be a promising treatment approach and we propose to further investigate possibilities and effects of such interventions for patients with severe disorders of consciousness.

Source: https://www.tandfonline.com/doi/full/10.1080/09602011.2021.1886119

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