Prepulse Inhibition in Youth Contact Sports Players
Condition: Reflex, Abnormal
MeSH terms: Reflex, Abnormal
Study type: Observational

Summary: 
      The study's main research question will be investigating whether or not there is a
      significant difference in Prepulse Inhibition (PPI) as well as startle response probability
      and magnitude between contact and noncontact youth sports players. The study team will test
      these questions using a controlled laboratory scenario in which the presentation of startle
      stimuli can be observed, measured, and quantified in order to compare the results between the
      two sample populations. During preliminary testing, the study team can predict that there
      will be no significant differences between contact sports players and noncontact sports
      players in their startle reactivity and level of exhibited PPI. Based on previous literature,
      the study team hypothesizes that those in the contact sports group will experience greater
      startle reactivity and less PPI than those in the noncontact sports group when they are
      tested at the end of their sports season. Using this information, the present study will
      allow for additional understanding of the neurological and physiological behaviors associated
      with subconcussive head impacts.

      This study will assess and determine whether prepulse inhibition in youth contact sports
      players and non-contact sports players, both before and after a sports season, will
      significantly differ. Measures will include the startle magnitude, startle probability,
      reaction time, and accuracy of tone detection responses.
    

Detailed description: 
      Our main research question will be investigating whether or not there is a significant
      difference in PPI, as well as startle response probability and magnitude between contact and
      noncontact youth sports players. The study team will test these questions using a controlled
      laboratory scenario in which the presentation of startle stimuli can be observed, measured,
      and quantified in order to compare the results between the two sample populations. During
      preliminary testing, the study team can predict that there will be no significant differences
      between contact sports players and noncontact sports players in their startle reactivity and
      level of exhibited PPI. Based on previous literature, the study team hypothesizes that those
      in the contact sports group will experience greater startle reactivity and less PPI than
      those in the noncontact sports group when they are tested at the end of their sports season.
      Using this information, the present study will allow for additional understanding of the
      neurological and physiological behaviors associated with subconcussive head impacts.

      This study will assess and determine whether prepulse inhibition in youth contact sports
      players and non-contact sports players, both before and after a sports season, will
      significantly differ. Measures will include the startle magnitude, startle probability,
      reaction time, and accuracy of tone detection responses.

      The current study is a case-control study, examining the contact sports players as the
      testing sample and the noncontact sports players as the control sample.

        -  Participants will arrive and hear an introduction of the study.

        -  Participants (and their parent/guardian if under the age of 18) will read and sign an
           informed consent and/or informed assent form.

        -  Participants will complete a series of questionnaires prior to electrode placement.

             -  The Health History Questionnaire will be completed first to determine participant
                eligibility.

             -  The STAI will be completed next to be used for further analysis in the data
                compilation.

        -  Participants will have three electrodes placed on the skin.

             -  Two electrodes will be placed underneath the left eye as the nasal and temporal
                electrodes.

             -  One electrode will be placed on the left temple as the ground electrode.

             -  These electrodes connect to the Biopac apparatus, the software that measures the
                participant's EMG activity.

        -  The procedure of the study will be thoroughly explained to the participants. They will
           be instructed to wear headphones that will deliver the acoustic startle stimuli and to
           remain as still and quiet as possible during the startle blocks.

             -  There will be a total of two startle blocks: baseline and testing.

             -  The baseline startle block will consist of a combination of prepulses at 70
                decibels of 800 and 1000 Hz frequency tones for a duration of 30 milliseconds
                presented with an onset of 120 milliseconds prior to the presentation of the
                startle stimulus of 100 decibels of broadband noise for 50 milliseconds on some
                trials.

             -  The testing block will also consist of prepulses at 70 decibels of 800 and 1000 Hz
                frequency tones for a duration of 30 milliseconds presented with an onset of 120
                milliseconds prior to the presentation of the startle stimulus of 100 decibels of
                broadband noise for 50 milliseconds on some trials. For the testing block,
                participants will be asked to respond on a keypad when they hear the lower prepulse
                tone of 800 Hz.

             -  Startle stimuli will be presented via headphones. Startle stimuli will be presented
                from the Superlab software program which will run from the testing room.

        -  After the testing block, the electrodes will be removed from the participant's skin.

        -  Participants will be thoroughly debriefed on the aims of the current study.

      This study will take place in the MRI suite of Wake Forest Baptist Health. A single room
      within the suite will be designated for the PPI testing, in order to control for external
      noise factors.

      After the consent process, subjects will be asked to fill out a brief health history
      questionnaire. This is for the purpose of determining the subject's eligibility to
      participate in the study. Subjects will also be asked to complete an STAI form, and this will
      be used later during data analysis.

      This study will last approximately one hour. The introduction and consent process will take
      about 10 minutes. The questionnaire process is expected to take about 10 minutes. The
      application of sensors should take about 10 minutes. The testing process, including the
      explanation of both startle blocks, should last about 20 minutes. The sensor removal and
      debriefing process will last about 10 minutes.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Participants who participate on a sports team who range in age from 13 to 19.
      
Keywords: Prepulse Inhibition; Startle Response