The investigator have planned to study the efficacy of long-term tPCS in these patients of
neurodegenerative ataxia. Anodal stimulation will be used for cerebellum and cathodal
stimulation for the spinal stimulation.
After the screening visit and inclusion, all patients will be randomized into daily
cerebello- spinal tPCS or sham stimulation. Randomization will occur in a ratio of 1:1. After
a washout period of three months, all patients will be crossover to the other intervention.
By the end of the study all patients will receive a cycle of tPCS and a cycle of sham
stimulation. Clinical rater will be blinded throughout the whole study.
After screening and randomization, all patients will undergo a baseline clinical assessment.
A blinded researcher will apply the Scale for the Assessment and Rating of Ataxia (SARA) and
the Cerebellar Cognitive Affective Syndrome Scale (CCAS). Also will asses speech, gait, and
upper limb motor function. Speech will be assessed according to the established protocol.
Gait will be assessed via Gait Carpet. Upper limb motor function will be assessed by a
robotic arm called KinArm. At the initial visit, the patient will be trained and tolerability
and ability to self-administer tPCS at home will be determined.Assessments will be carried
out 2 weeks after the first intervention (either real or sham tPCS) .Then, patients will be
reassessed at 1-month and 3-months follow-ups. After a washout period of 3 months since the
last visit, each patient will receive the opposite treatment and undergo the same
standardized assessment as in the first phase.
tPCS will be delivered through a pair of saline-soaked (0.9% NaCl) surface sponge electrodes
(7 × 5 cm2, for the anodal cerebellar electrode; 8 × 6 cm2 for the cathodal spinal
electrode). Anodal stimulation will be applied on the scalp over the cerebellum area (2 cm
under the inion) and the cathode will be placed over the spinal lumbar enlargement (2 cm
under T11). During anodal stimulation, a constant current of 2 mA will be applied for 20
minutes. For the sham condition, electrode position will be same, but the electric current
will be ramped down 5 seconds after the beginning of the stimulation to make this condition
indistinguishable from the experimental active stimulation.
Participant's speech will be recorded using a head-mounted microphone (AKG-c520) and a
digital recording device (Zoom H4nPro) while performing the following calibrated tasks.
Calibration involves a sound level meter placed at 15cm from the mouth while talker says 'ah'
at 70dBA. The following speech tasks will be assessed-
Prolonged 'ah'.
Rapid repetitions of the sounds "puh", "tuh", and "kuh".
Two productions of a sentence with selected speech sounds (s, sh, p, b, t, i, a, u, ae,
ai). "She saw Patty buy two poppies."
Two times louder production of a sentence with selected speech sounds. "She saw Patty
buy two poppies."
Repetition of a continuous vowel at normal and fast rates. 'eye-eye-eye-eye-eye' without
making any voice breaks or pauses".
Read aloud a section of a standard passage - standard rainbow passage
Monologue. Talk for two minutes about an interesting vacation (or an interesting hobby
or activity).
For gait, the Zeno walkway it will be used. The Zeno walkway will be used in conjunction with
the ProtoKinetics Movement Analysis Software (PKMAS). This detects pressure data during gait,
balance, and additional movement protocols.
For measuring upper limb movements, KinARM will be used which is the short form of a robotic
device. The KinARM initially provides the patients with multiple points to reach in the
screen and the patients would try to reach these points using the KinARM handle.
All quantitative data will be expressed in term of medians and interquartile range. For
qualitative variables, data will be expressed in total numbers and proportions (percentages).
Quantitative results from every assessment (T0, T1, T2 and T3) will be compared between sham
and real stimulation using the Wilcoxon signed-rank test for paired samples. For qualitative
data, variables will be compared using the chi-square (χ 2) test or the Fisher's exact test
when appropriate. For all analyses a p<0.05 was specified as statistically significant.