Transient transport studies have widely been recognised as a valuable complement to steady-state analysis for the understanding of transport mechanisms. Perturbative experiments have therefore been used extensively to investigate conventional plasma regimes in several machines [1]. They have also been used to investigate the nature of transport in the electron barriers observed in the RTP tokamak [2]. This paper presents the first attempt to use perturbative techniques to investigate transport in plasmas characterised by a strong ion and electron Internal Transport Barrier (ITB).