La Primera Ley de Organización Judicial de 31 de diciembre de 1857

Communicative participation was the key outcome measure in my study. I found that read sentence intelligibility did not predict communicative effectiveness and

participation, and that conversational intelligibility was only a modest predictor of

communicative outcomes. This adds to the extant body of literature (see section 2.4.2.7) emphasising the importance of communicative participation, rather than focusing on the ICF Impairment level.

For the sake of concision, discussion of clinical practice in this section is

exclusively from a UK perspective. Current clinical guidelines for speech and language therapy in the UK (Royal College of Speech and Language Therapists, 2005, Royal College of Speech and Language Therapists, 2006) do not contain a specific section on PD. There is the potential of over-generalising across conditions that do not share the same pathogenesis. While PD is an acquired motor speech disorder and a progressive neurological disorder, as seen in chapter 2, it is a wide-ranging condition which may impact on autonomic function, cognitive status and psychiatric status. Therefore, more specific guidance for PD may be beneficial, especially in the light of extensive

investigations of communication in PD since the publication of these guidelines, most notably by Professor Nicholas Miller and colleagues at the University of Newcastle.

While no specific guidance is given for the treatment of individuals who have cognitive impairment as part of a progressive neurological condition, guidelines for speech and language therapy with clients with dementia recommend specific focus on

conversation to enhance communication. Guidelines for clients with dysarthria

recommend perceptual evaluation of speech impairment, a communication skills profile and a focus on the psychosocial impact of the condition. Recommended treatment may be physiological, compensatory strategies or involve the use of augmentative technology. Service organisation guidance for clients with progressive neurological conditions

recommends promoting and maintaining functional independence as far as the condition allows. Service organisation guidance for clients with acquired motor speech disorders emphasise that impairment should be sub-ordinate to activity and participation.

However, recent systematic reviews conclude that there is still insufficient high- quality evidence to conclusively support the efficacy of speech and language therapy in PD or to determine which therapy techniques are the most effective (Herd et al., 2012a, Herd et al., 2012b). Moreover, the mechanisms of action remain unconfirmed. A recent national survey of the practices of 185 UK speech and language therapists with regards to PD (Miller et al., 2011b) found that assessment tools beyond the ICF impairment level were used by relatively few therapists and that psychosocial issues did not frequently form a prominent focus of therapy relative to impairment-level aspects of speech. However, the vast majority offered some psychosocial support either through group therapy, counselling, discussion, work with the family or referral to other services. Miller et al (2011b) suggest that many therapists may not emphasise communicative activity and participation sufficiently, relative to guidelines. There is anecdotal evidence from people working in the field that the introduction of the ICF has led to an increased focus on activity and participation in the education of student speech and language therapists, with consequent beneficial effects on the service offered by newer recruits to the profession. However, concrete intervention approaches at the participation level appear to be lacking.

As reported in this thesis and in Baylor et al (2013a), CPIB shows promise as a valid and reliable assessment tool for communicative participation in PD. My QCA also demonstrated satisfactory participant acceptability for CPIB. Although this thesis and the extant body of literature support a focus on communicative participation, it is unclear whether this should involve the use of a standardised assessment tool. In a grounded theory investigation of what participation meant to people with a range of disabilities (Hammel et al, 2008), respondents stated the importance of being able to define participation themselves rather than having to meet prescribed societal expectations of what participation should mean. This raises questions about whether a set-item

questionnaire such as CPIB is the best way to address the assessment of communicative participation with clients, or whether an open discussion would be more suitable.

As a cross-sectional investigation, my study does not offer definitive evidence of causal relations between cognitive status, speech impairment and communicative outcomes. Therefore, it may be worth considering embedding speech impairment and communicative participation into a natural history study of PD using an incident cohort. This would provide a clear pathway of the temporal sequence and prevalence of speech and communicative impairments, and clarify the causal relation with cognitive status. Additionally the use of a thorough neuropsychological assessment, meeting the level two MDS criteria (Litvan et al, 2012), could help clarify which aspects of cognitive function are most important for speech and communicative outcomes. As discussed in section 7.3, an assessment of social cognition could also be included.

It would be worth conducting a further investigation of the relationships between the acoustic characteristics of the speech of PwPD, since this aspect of my study was limited by resource constraints. The use of a team of phonetic analysts would enable a larger sample size to be analysed phonetically. More resources would enable an age- matched group of assessors to be recruited from a different region of the country. This could be incorporated as an assessment of the mechanism of action of speech and language therapy as a component of a randomized controlled trial of speech and language therapy techniques for PD. There have been on-going bids for a randomised controlled trial, and the potential of incorporating a mechanism of action component has been discussed.

Once associations between cognitive status and a range of other PD outcomes have been clarified, including the pathway to dementia (see section 2.3.1.4), further research could be conducted into identification and treatment of cognitive impairment in PD. An audit of current cognitive screening procedures could be performed, and

subsequent research conducted to identify the optimal time and tools to identify mild cognitive impairment in PD. An MDS evidence-based review (Seppi et al., 2011)

concludes that rivastigmine is the only pharmacological treatment for dementia in PD for which there is sufficient extant evidence of efficacy to recommend clinical use. Further research could be conducted into potential treatments for earlier cognitive impairment in PD, including pharmacotherapy, cognitive training and exercise.

Additionally, I obtained consent from all participants for audio-visual recordings made as part of my study to be used for responsible teaching and further research

purposes. Excerpts from my recordings could be used by my supervisors or other staff, to increase the familiarity of allied health and nursing students with the speech of PwPD. This could bring significant educational benefit and improve the future clinical practice of these students.