Ataxia refers to a group of neurological disorders characterized by impaired coordination and balance due to dysfunction in the cerebellum or its connections. Traditional therapeutic approaches for ataxia have shown limited efficacy, prompting researchers to explore alternative interventions. Non-invasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), and intermittent theta burst stimulation (iTBS), have emerged as potential therapeutic options. The aim of this study is to investigate the combined effect of tACS-iTBS on balance functions in ataxia disorders.
Ataxia comprises a heterogeneous group of acquired or inherited disorders primarily involving cerebellar dysfunction, leading to impaired coordination and motor learning. Traditional treatments, including medication and physical therapy, often provide limited symptomatic improvement. Non-invasive brain stimulation (NIBS) techniques have emerged as promising tools for modulating cerebellar activity and enhancing motor function. Transcranial magnetic stimulation (TMS) can influence cortical excitability and plasticity, and studies have shown that high-frequency cerebellar rTMS can improve motor performance in spinocerebellar ataxia. Intermittent theta burst stimulation (iTBS), a patterned form of TMS, has demonstrated benefits in other movement disorders, suggesting potential applicability to ataxia. Transcranial direct current stimulation (tDCS), which modulates neuronal excitability via weak electrical currents, has shown improvements in static and dynamic balance in degenerative cerebellar ataxia. Transcranial alternating current stimulation (tACS) modulates neural oscillations and early studies indicate possible benefits for ataxia symptoms. Recent work has explored combining NIBS modalities to enhance neuromodulatory effects. In preliminary experiments, combined cerebellar tACS and iTBS increased MEP amplitudes more than iTBS alone, with effects lasting up to 30 minutes. These synergistic effects may translate into improved motor performance, coordination, and balance. The present study aims to investigate whether combining real or sham tACS with iTBS produces greater benefits than exergaming biofeedback alone in individuals with ataxia. A cross-over design will be used so that each participant serves as their own control. The primary outcomes will include motor coordination, balance, and cerebello-cortical plasticity. The rationale is that tACS may optimize oscillatory activity while iTBS enhances excitability, thereby jointly promoting neuroplasticity in cerebellar networks. The study will recruit individuals diagnosed with ataxia and assess the therapeutic potential of combined NIBS interventions.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
30
Stimulation will be applied to the cerebellum. The tACS session duration will be 190 seconds with a frequency of 5 Hz coupled with iTBS (coil positioned tangentially with respect to the scalp)(600 pulses consisting of bursts of 3 stimuli at 50 Hz, repeated at intervals of 200ms, with an intensity of 80% of active motor threshold -AMT-) (Huang et al., 2005) for a total duration of 190 seconds (repeated over both cerebellar hemispheres after a 15-minute rest period). The exergaming will be performed with an adaptive system, comprising a force platform connected to a computer. The system is designed to enhance standard balance rehabilitation programs by guiding the user's performance of prescribed physical exercises through a video interface. Patients will perform 3 different exercises (10 minutes of training for a total of 30 minutes): latero-lateral and antero posterior load shift, omnidirectional displacement (combined latero-lateral and antero-posterior loading).
Stimulation will be applied to the cerebellum. The tACS session duration will be 10 seconds with a frequency of 5 Hz coupled with sham iTBS (coil positioned perpendicularly with respect to the scalp)(600 pulses consisting of bursts of 3 stimuli at 50 Hz, repeated at intervals of 200ms, with an intensity of 80% of active motor threshold -AMT-) (Huang et al., 2005) for a total duration of 190 seconds (repeated over both cerebellar hemispheres after a 15-minute rest period). The exergaming will be performed with an adaptive system, comprising a force platform connected to a computer. The system is designed to enhance standard balance rehabilitation programs by guiding the user's performance of prescribed physical exercises through a video interface. Patients will perform 3 different exercises (10 minutes of training for a total of 30 minutes): latero-lateral and antero posterior load shift, omnidirectional displacement (combined latero-lateral and antero-posterior loading).
IRCCS Santa Lucia Foundation
Rome, Lazio, Italy
RECRUITINGChanges in the International Cooperative Ataxia Rating Scale (ICARS)
ICARS was developed to quantify the level of impairment as a result of ataxia as related to hereditary ataxias. Score ranges from 0 to 100 where 100 indicates severe ataxia.
Time frame: Baseline (1), 2 weeks from baseline (1), Baseline (2), 2 weeks from baseline (2)
Changes in the Short Form-36 Health Survey (SF-36)
SF-36 is an outcome measure instrument that is often used, well-researched, self-reported measure of health. Scores range from 0 to 100 for each domain, where 100 indicates a more favorable health-state.
Time frame: Baseline (1), 2 weeks from baseline (1), Baseline (2), 2 weeks from baseline (2)
Changes in postural control
Instrumented postural stability will be assessed using a 75 cm (length x width) static force platform (PlatformBPM 120, Physical Support Italia, Italy). The signals will be amplified and acquired using dedicated software (Physical Gait Software Vv. 2.66, Physical SupportItalia, Italy). The length of the center of pressure (CoP) trajectory (mm) will be measured as indicator of the postural stability. An increase in the length of CoP indicates a severe impairment in postural control.
Time frame: Baseline (1), 2 weeks from baseline (1), Baseline (2), 2 weeks from baseline (2)
Changes in cortico-spinal excitability
Twenty Motor evoked potentials (MEPs) will be collected from left and right primary motor cortex with single pulses of transcranial magnetic stimulation (TMS) set at 1 mV. An increase in the MEPs amplitude indicates an improvement in cortico-spinal activity recorded from the first dorsal interosseous and tibialis anterior muscles.
Time frame: Baseline (1), 2 weeks from baseline (1), Baseline (2), 2 weeks from baseline (2)
Change in the Scale for the Assessment and Rating of Ataxia (SARA)
SARA is a clinical scale developed to assess a range of different impairments in cerebellar ataxia. The scale is made up of 8 items related to gait, stance, sitting, speech, finger-chase test, nose-finger test, fast alternating movements and heel-shin test. Score ranges from 0 to 40 where 40 indicates severe ataxia.
Time frame: Baseline (1), 2 weeks from baseline (1), Baseline (2), 2 weeks from baseline (2)
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