A thesis submitted in partial fulfilment of - Queen Margaret University

therapy materials used in rehabilitation they are not considered influential on the
recovery of language itself. Therefore, the remaining three cognitive processes
will be discussed below: attention, memory and executive function.
There is increasing evidence that impairment to the process of attention may
either be a part of or co-exit with aphasia (Murray, 1999), interacting with
language processes and thereby contributing to communication impairment
(McNeil, Odell, and Tseng, 1991). Attention is thought to “gate” the processing
of information in visual, auditory and somatosensory perception (Robertson and
Murre, 1999), where the brain selectively pays attention to experiences it
expects, incorporating them through learning into its knowledge of the world
(Grossberg, 1999). Vakil, Hoffman and Myzliek (1998) studied the effects of
active and passive learning in adults and reported that individuals who
participated in active training performed better and retained more durable
memory traces than those who participated in passive training. Therefore as
previously discussed (see section 2.5.2), cortical plasticity occurs with the
acquisition of new information which requires attention and continuous practise,
therefore neuronal reorganisation is not a passive process but requires active
attention during the task.
As Helm-Estabrooks (2002) asserts, aphasia therapy is a learning process and
adequate memory processes are required to remember the newly learned
information. Memory processing impairments are common following a stroke
(Murray, 2004, 2002; Skeel and Edwards, 2001; Burgio and Basso, 1997;
Wilson and Hughes, 1997 and Ween, Verfaellie and Alexander, 1996) and
therefore are often experienced by people with aphasia. However, memory
processing difficulties are not thought to be associated with specific lesion sites
and often persist despite good language recovery (Ween et al., 1996).
Impairment can occur at any of the three processing stages – encoding
(involving acquisition and consolidation of information), storage (creation and
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