def METHOD_NAME(confound, head_radius=50):
    """Compute framewise displacement.
    NOTE: TS- Which kind of FD? Power?
    NOTE: TS- What units must rotation parameters be in?
    Parameters
    ----------
    confound : pandas.DataFrame
        DataFrame with six motion parameters.
    %(head_radius)s
    Returns
    -------
    fdres : numpy.ndarray
        The framewise displacement time series.
    """
    confound = confound.replace(np.nan, 0)
    mpars = confound[["trans_x", "trans_y", "trans_z", "rot_x", "rot_y", "rot_z"]].to_numpy()
    diff = mpars[:-1, :6] - mpars[1:, :6]
    diff[:, 3:6] *= head_radius
    fd_res = np.abs(diff).sum(axis=1)
    fdres = np.hstack([0, fd_res])
    return fdres