COLECCIÓN “CUADERNOS DE DIRECCIÓN ASEGURADORA”

The participant was a 16-year-old male who had received a formal diagnosis of Tourette’s syndrome at the age of 8years. The participant had no additional diagnoses, however, elevated levels of anxiety had previously been an issue, for which the participant took the SSRI Sertraline (100mg). Some obsessive compulsive behaviours were also reported, although there was no formal

diagnosis of OCD. In addition to Sertraline the participant was also on a stable medication regime using both Clondine (200mg) and Aripiprazole (10mg).

6.2.2 Design

Phase 1

A schematic of all experimental procedures is summarised in Figure 6.1. During the first part of this case study, the participant and one of their parental guardians visited the University of Nottingham where baseline MRI scans and questionnaire measures (described below in 6.2.5) were collected. During this visit, the participant and their guardian were trained by the primary researcher (KD) to safely and effectively use the pre-programed tDCS machine. They then returned home with detailed instructions and the equipment needed to start the first phase of this home use study.

138 Over 10 consecutive days, the participant received sham stimulation within the comfort of his own home. Application of the stimulation was

monitored remotely by the primary researcher (KD). With the exception of a few issues on the first day, application and use of tDCS went well. During the

stimulation period, ten-minute video segments of the participant passively watching the television were recorded every other day. The first video clip was assessed to give guidance regarding camera positioning and lighting to ensure that tics could clearly be seen. After this, the videos were not seen by the primary researcher (KD) so that they could later be coded with the researcher blind to the condition.

Four days after the final sham stimulation the participant returned to the University of Nottingham to repeat the questionnaire measures and to be scanned. The participant then returned home to complete a further 10 days of consecutive 1mA cathodal stimulation and video recordings every other day. Five days after the last application of tDCS the participant returned to the University of Nottingham for follow up questionnaires and scanning. An additional follow up was completed approximately one month later.

Phase 2

After reviewing the findings of the first study, it was decided that a second phase of the experiment would be run in which a stronger intensity of tDCS would be used (Figure 6.1B). Two months elapsed between the final 1mA cathodal stimulation and the new data collection. As sham stimulation appeared to have a limited effect on tics, the effects of a sham protocol were not

measured again in phase 2. Instead a more extensive baseline was measured in which home video recordings were included in addition to scans and

questionnaire measures. Following the 10-day baseline, a further 10 days of consecutive stimulation were completed, this time using 1.5mA cathodal

stimulation. During this time, videos were also recorded every other day. A final follow up including scanning and questionnaire measures was taken five days after the last stimulation. The participant was always blind to the experimental

139 condition, and all data were analysed with details of experimental condition removed.

Figure 6.1. Schematic showing the study design. A. shows the initial baseline, sham, 1mA cathodal and 1 month follow up conditions which were tested. B. shows the second phase of the study in which 1.5mA cathodal stimulation was tested against a new baseline. Two months elapsed between the final 1mA cathodal stimulation and the measurement of the second baseline.

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6.2.3 tDCS of the supplementary motor area (SMA)

tDCS was delivered via a NeuroConn DC stimulator mobile (GmbH, Ilmenau, Germany). This was programed in advance by the researcher (KD) to deliver one of three options (sham, 1mA,

1.5mA). The stimulator was set so that it could only be used once within a 22 hour period and the settings could not be changed by anyone other

than the researcher. In the first session, the stimulator was set to deliver a 20-minute sham protocol, in which the current was ramped up for 15s, held constant at 1mA for 30s and then ramped down over a further 15s period. For the second part of the initial

study the machine was programed to deliver 1mA stimulation for 20 minutes with a ramp up and ramp down time of 15s at the start and end. In phase 2 of the study the stimulator intensity was increased to 1.5mA and kept constant for 20 minutes; the ramp up and down time were also set to 15s. The current was run between two saline soaked sponge covered electrodes, the smallest of which measured (25cm2_{) and was placed approximately over the SMA. This location} was identified in accordance with previous studies (Enticott et al., 2012; Finis et al., 2013; Mantovani et al., 2007), in which the 10-20 EEG system was used to identify the site which is 15% of the distance between the nasion and inion, anterior of the CZ location. The ‘reference’ electrode measured 100cm2 _{and was} placed on the upper deltoid muscle on the participant’s right arm (Figure 6.2). The participant and their guardian were trained to apply the stimulation during the baseline session. Over the first few sessions the electrode placement was monitored remotely via photographs showing electrode montage.

Communication and support were provided throughout the studies duration.

Figure 6.2. Schematic of

electrode placement with the smaller electrode placed over the SMA, and the larger one placed over the upper deltoid muscle of the arm.

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