For example, the same individual

often makes both semantic and phonological errors in word retrieval. Furthermore, individuals’ word production is often influenced by variables held to reflect different levels of processing. Secondly, almost all interventions involve participants in producing the target word thereby strengthening links from word meaning to word form (Howard, 2000) and potentially benefiting everyone with difficulty at some stage(s) in word production. The findings from therapy studies for spoken word-production deficits are somewhat mixed with regards to the extent of the effect of treatment. Limited or no BYL719 generalisation to untreated items is the result across the majority of intervention studies including those investigating: errorless learning (Fillingham et al., 2006), production of nouns and verbs (Raymer et al., 2007), a cueing hierarchy (Thompson et al., 2006) and contextual priming (Renvall et al., 2007). There are a few exceptions to this AZD2281 ic50 pattern. Interventions focused on process, particularly those with a semantic component (Renvall et al., 2003; Coelho et al., 2000; Boyle, 2004) are held to influence production of untreated items to some extent. Phonological Feature Analysis (Leonard et al., 2008) also resulted in generalisation to untreated items

for 3/10 participants. Generalisation to homophones of targets has been found from intervention with a cueing hierarchy (Biedermann and Nickels, 2008) but not to phonologically or semantically related control items. The distinction PIK3C2G between therapy for semantic deficits (which targets this level) and semantic therapy for word production is important. In the former, ‘semantic’ tasks such as categorisation or semantic feature judgements are employed with the aim of improving a person’s

semantic processing; this should influence comprehension and production. In the latter, while meaning is involved in the task, e.g., through pictures, the intervention facilitates word production rather than semantic processing itself. An example is the study by, Howard et al. (2006) who demonstrated that manipulating the ‘depth’ of semantic processing did not influence naming outcome. Participants that benefited the most from semantic therapy for word production had a deficit in the links between word meaning and form (stage 2 on the model of word production outlined above). These results combined suggest this intervention is not actually operating at a semantic level but rather strengthening links between meaning and form. Thus, there is consensus that repeatedly activating the links between an item’s meaning and form [stages (1) and (2) above] often results in item specific improvement in naming (Howard, 2000), and this is the likely focus for change in a large number of therapy studies. However, the picture may not be as bleak as it first appears.