You can use this:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class RTPCListener : MonoBehaviour {
//set your RTPCID to the name of your desired gameparameter (under GameSyncs)
public string rtpcID;
// Update is called once per frame
void Update () {
// RTPCValue_type.RTPCValue_Global
// for whatever reason, this constant isn't exposed by name by WWise C#/Unity headers
int type = 1;
// will contain the value of the RTPC parameter after the GetRTPCValue call
float value;
// retrieves current value of the RTPC parameter and stores it in 'value'
AkSoundEngine.GetRTPCValue( rtpcID, gameObject, 0, out value, ref type );
//
// use 'value' here
//
// e.g. transform.localScale += Vector3( value, 0, 0 );
// which would scale by the value of the RTPC parameter
}