Lee Silverman voice treatment versus standard NHS speech and language therapy versus control in Parkinson’s disease (PD COMM pilot): study protocol for a randomized controlled trial

Recruitment will take place from 11 neurology and elderly care NHS clinics from a mix of urban and rural areas in the UK. The UKCRN networks will be asked to adopt the study to support recruitment. Informed consent will be obtained for all participants recruited into the study.

For a feasibility study no formal sample size calculation is required. We aim to recruit at least 60 participants over 21 months from the 11 sites (at least 20 participants in each arm of the trial) which will provide enough data to inform a future phase III trial[16].

The inclusion criteria are deliberately broad to allow the inclusion of a wide spectrum of typical people with PD. People with PD are eligible for this study if they: (1) have idiopathic PD defined by the UK PDS Brain Bank Criteria[17] and (2) report problems with speech or voice when asked (or their carer does).

The exclusion criteria for this study are as follows: (1) dementia, as defined clinically by the physician, (2) evidence of laryngeal pathology including vocal nodules, a history of vocal strain, or previous laryngeal surgery within their medical records or from discussions with client, as LSVT® is not appropriate for this group[9], (3) received SLT for PD speech or voice related problems in the past two years, based on a detectable treatment effect reported at 24 months following LSVT®[18], and (4) investigator is certain that the person with PD will not require SLT during the first six months of the trial.

The trial is 12 months duration, but participants randomized to the no-intervention group can be referred for therapy after 6 months (see below).

Potential participants who meet the eligibility criteria will be initially approached in their normal outpatient appointments. If interested, they will be given a patient information sheet and time to consider the trial and discuss it with friends and family. A further meeting will be arranged to answer any questions prior to informed consent being taken. Following consent, participants will complete baseline assessments prior to randomization. Participants will be informed of their treatment allocation and, if allocated therapy, be referred for the initial assessment. Baseline vocal assessments may be performed after randomization but must be completed prior to the start of therapy.After completing the baseline questionnaires, participants will be randomized between the three groups at a ratio of 1:1:1 via the Birmingham Clinical Trials Unit (BCTU) telephone randomization service (Figure 1). This secure central randomization service is available between 9 am and 5 pm weekdays and will ensure the concealment of treatment allocation. A computer-generated randomization list will be used. Participants will be informed of their treatment allocation but assessors will remain blind to treatment allocation. If allocated to an intervention arm, referral to the appropriate speech and language therapist will occur immediately following randomization. All personal information obtained for the study will be held securely and treated as strictly confidential.

The interventions will be delivered in outpatient and community settings. The setting will be dependent on the provision of the speech and language therapy and the needs of the individual participant. Logs summarizing the intervention will be kept by the therapist and will be used to monitor adherence and, in the case of the standard SLT intervention, to document content.

The intervention will replicate the dose and content prescribed by LSVT®, consisting of 16 sessions of between 50 and 60 minutes duration delivered over four weeks[9, 19]. Participants will also be set 5 to 10 minutes of home practice on treatment days, and up to 30 minutes of home practice on non-treatment days[20].

LSVT® comprises maximum effort non-speech and speech drills. The non-speech drills include production of sustained ‘ah’ phonation at a single pitch and pitch glides (moving from low pitch to high pitch and vice versa on production of sustained ‘ah’). These exercises are for improving voice production and flexibility without speech. The speech drills utilize a hierarchy of speech tasks moving from single words through phrases and onto conversational speech. Each step in this hierarchy puts increased demands on the speaker and challenges the speaker to maintain maximal speech production.

The content and dose of standard SLT is poorly defined within the published literature. For this reason, the standard therapy intervention will encompass all SLT techniques that are not LSVT®. Treatment will be individualized and may include (but will not be limited to) any of the following: exercises targeting respiration, phonation, articulation[12, 13], behavioral strategies to reduce prosodic abnormality[21], and the use of augmentative and alternative communication (AAC) strategies and therapeutic devices to improve functional communication[22]. The dose will be determined by the participant’s individual needs, but will not exceed eight weeks of treatment. It is most likely to reflect the median dose reported in a survey of current UK speech and language therapy practice for PD by Miller et al.[8] of 6 sessions averaging 45 minutes delivered over 42 days.

If allocated to the control group participants with continue with their standard care and receive no SLT input for at least six months post-randomization unless their clinician deems it to be medically necessary. The six month SLT exclusion time for this group was decided in conjunction with therapists. After six months participation in the trial people in the control arm can be referred for therapy by their usual specialist through NHS referral pathway.

Data on various outcomes measures will be collected as part of the PD COMM pilot in order to assess which outcomes are appropriate to take forward to the phase III RCT. These include both participant, therapist, and carer completed questionnaires and measures. Outcome measures will be assessed at baseline (pre-treatment), 3 months (post-randomization - to allow for any delays in referral to therapy and the varying intervention lengths), 6 months, and 12 months post-randomization (to see if any benefit is maintained). Assessment will take place at the therapy departments of participating centers and will be conducted when the participant is ‘on’ medication (if medicated). Vocal assessment of intelligibility of dysarthric speech (AIDS), loudness, and comprehension will be recorded and assessed by assessors masked to the participant’s group allocation. Participant completed questionnaires will be conducted via post.

Effectiveness of communication will be measured using the self-report Voice Handicap Index (VHI)[23]. The VHI has previously been used as an outcome measure in an extended LSVT® trial for PD[20]. Intelligibility will be assessed using AIDS[24]. Participants will be digitally recorded speaking randomly generated words and sentences from AIDS. These will then be transcribed by three blinded assessors. Vocal loudness will be measured through sound pressure level (in decibels) for a sustained vowel (’ah’) phonation, the reading of a ‘rainbow passage” (an articulation exercise including all the normal sounds of spoken English), and speaking freely during a self-chosen monologue[18]. These will be audio-recorded and assessed by a blinded assessor. A comprehensibility assessment will be made using a picture, the ‘cookie theft’ picture from the Boston diagnostic aphasia examination[25]. This will be digitally recorded and assessed by three blinded assessors. Quality of life (QoL) will be recorded through two self-report measures; the PD-specific 39 point Parkinson’s Disease Questionnaire (PDQ-39[26] and the voice specific Voice-Related QoL scale (V-RQOL)[27]. Participation restriction related to speech and communication will be assessed using the self-report Living with Dysarthria questionnaire (LwD)[28]. The effect on carers will be measured through the self-report Parkinson’s Carers’ Quality of Life Questionnaire[29]. Screening and treatment logs will also be completed to collect data relating to acceptability of the intervention and follow-up, recruitment and retention rates, and participant adherence to treatment allocation.

Health-related quality of life will be obtained using the EuroQol 5 Dimensions (EQ-5D)[30], capability measurement using the ICEpop CAPability measure for Older people (ICECAP-O)[31, 32], and resource use using a bespoke self-completion questionnaire. For time points of assessment see Table 1.

The PD COMM pilot trial has been granted National Research Ethics Service (NRES) approval (Reference: 11/WM/0343) and has an international standard randomized controlled trial number (ISRCTN75223808).

The trial also has a joint Data Management Committee (DMC) and Trial Steering Committee (TSC) to monitor the progress and safety of the trial and ensure the protocol is adhered to. The joint TSC/DMC includes an independent chair and two further independent members.

The SLT interventions within this pilot study are considered low risk. There may be a small increased risk of vocal strain or abuse and this small risk will be clearly stated in the participant information sheet. Every effort will be made to minimize the risk of vocal strain or abuse. Speech and language therapists are trained to identify and rehabilitate vocal strain, so if present, the therapists can quickly address it. No other risks are expected to arise from taking part in the study. It is therefore reasonable to only collect targeted-treatment related adverse events and serious adverse events such as vocal strain or abuse. These will be collected on a study serious adverse event form.