Autonomic Modulation in Athletes and Non-Athletes With Spinal Cord Injury During Task in Virtual Reality Environment
Condition: Spinal Cord Injuries
MeSH terms: Spinal Cord Injuries; Wounds and Injuries
Study type: Observational

Summary: 
      The study consisted in the analysis of the autonomic modulation of the heart rate by the
      Heart Rate Variability of the participants at rest for 5 minutes, and during physical
      activity of 8 minutes, through a virtual reality game. The data capture was performed using a
      cardio-frequency meter with belt placed on the volunteer's trunk and, in addition,
      questionnaires, functional classification scales and personal data collection were applied.
    

Detailed description: 
      This is a cross-sectional study, approved by the Ethics and Research Committee of the Medical
      School of the Federal University of São Paulo (UNIFESP) registered under CAAE
      793517.1.0000.5505. The recruitment of non-athletes was carried out at the Acreditando
      Rehabilitation Center and the athletes were recruited at the Faca na Cadeira Institute, ICEL
      and Clube Espéria. Participants were enrolled in the study after signing the Free and
      Informed Consent Term. Convenience sampling technique was used with data collected from March
      2017 to October 2018 Participants The study included athletes and non-athletes with a
      confirmed medical diagnosis of SCI, with voluntary extension of elbows and wrist, active
      trunk control, and who had already completed rehabilitation. For the athlete group,
      participants had to fulfill the minimum criteria for defining an active athlete, described in
      the next section. Also, a control group of able-bodied subjects, approximately paired by age
      and sex wit the AG and non-athlete groups were recruited. Participants were excluded if they
      presented with impairments to the upper limbs that interfered with the performance during the
      game, were diagnosed with heart disease or other neurological disorders , were using
      medication that were not part of their usual routine or that influenced the cardiac and
      nervous systems, and presented an error greater than 5% in the analysis of HRV.

      Assessment of function The Funtional Independence Measure (FIM) and the Spinal Cord
      Independence Measure Version III (SCIM III) were used to classify functional independence.
      The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI)
      was employed to assess the level and severity of injury. To classify the physical activity
      levels of the participants, the the Physical Activity in Athlete Questionnaire and the
      Leisure Time Physical Activity Questionnaire for Non-Athletes with Spinal Cord Injury
      (LTPAQ-SCI) were employed.

      Assessment of Heart Rate Variability For the HRV assessment, participants were instructed not
      to consume alcohol, caffeine or smoke 24 hours before the test. The procedures to measure HRV
      were conducted according to the guidelines from the Task Force of the European Society of
      Cardiology and the North American Society of Stimulation and Electrophysiology and were
      recorded using the Polar V800 electrocardiographic measuring device (Polar Electro, Finland),
      with a sampling rate of 1000 Hz.

      The determination of the linear indexes of HRV for time and frequency was carried out using
      the software Kubios HRV (v. 3.3.0). The HRV data for time was analyzed using linear methods,
      using SDNN indices (standard deviation of the mean of all normal RR intervals) in
      milliseconds (ms); PNN50 (percentage of successive differences of the RR intervals with an
      absolute value greater than 50ms); RMSSD (square root of the mean square of the differences
      between adjacent normal RR intervals). Moreover, geometric methods such as, the RRTri
      (triangular index) and TINN (histogram interpolation of NN intervals), the indexes of the
      Poincaré graph with the SD1 (standard deviation of the instantaneous variability of the
      beat-to beat heart rate), SD2 (standard deviation of the long-term, continuous, RR interval
      variability), and the SD1/SD2 ratio-the ratio between the short- and long-term variations
      among the RR intervals and Parassympathetic Nervous System index (PNS index), Sympathetic
      Nervous System index (SNS index) and Stress index given by HRV Kubios, were employed. LF
      indices (low frequency spectral components, between 0.04 and 0.15 Hertz) were recorded in ms2
      and in standard units (nu); while HF (high frequency spectral components, between 0.15 and
      0.4 Hertz) was recorded in ms2 and nu; and the ratio of LF/HF in ms2.

      PROTOCOL For the three groups the HRV measures were captured in 2 instances: 1. For 5 minutes
      at rest in the seated position; and 2. During the VR activity, in which the individual
      executed movements according to a game in front of a computer for 8 minutes. The VR activity
      was performed using the game MoveHero, developed at the School of Arts Sciences and
      Humanities of the University of São Paulo (EACH-USP). The game consists of virtual balls that
      fall in pre-determined time intervals and spacial distribution in four imaginary columns on a
      computer screen. The participant must move in the direction of the balls to touch them as
      they reach four pre-determined targets placed to the sides of the player's avatar. The
      targets are numbered (1 to 4) and are placed in parallel at two different heights, two to the
      left and two to the right of the player's avatar.

      The game captures the participant's movements with a webcam, not requiring physical contact
      to perform the task. The participant must move his arms at 80% of their maximum lateral
      range. Before starting the task, the experimenter positioned the participant in a distance
      from the screen that allowed him/her to achieve the maximum lateral reach range for each side
      (left and right) when reaching towards the two farthest balls (1 and 4). From that position,
      the distance between the computer's table and the participant's feet was measured and the
      participant was asked to move his/her wheelchair to 80% of this distance. During the task,
      the participant had to wait for the balls to drop until they reached the pre-determined
      targets. When the balls reached the targets, the color of the balls changed to green, which
      prompted the participant to reach for them. Therefore, the game requires the participant to
      have a strategy of planning their movement to reach the targets at the same time as the
      balls.
    

Intervention name(s): Adaptation of autonomic nervous system to activity in virtual reality
Intervention type(s): Behavioral
Intervention description(s): heart rate variability assessed at rest and during a physical activity in virtual reality.
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        The study included athletes and non-athletes with a confirmed medical diagnosis of SCI,
        with voluntary extension of elbows and wrist, active trunk control, and who had already
        completed rehabilitation. For the athlete group, participants had to fulfill the minimum
        criteria for defining an active athlete, described in the next section. Also, a control
        group of able-bodied subjects, approximately paired by age and sex wit the and non-athlete
        groups were recruited.