Cerebellar TMS in treatment of a patient with cerebellar ataxia: evidence from clinical, biomechanics and neurophysiological assessments

Abstract

We describe a patient with a probable diagnosis of idiopathic late-onset cerebellar atrophy who shows improvement of limb coordination, speech, and gait following 21 days of transcranial magnetic stimulation (TMS) applied to scalp regions presumably corresponding to the cerebellum. This case study provides, for the first time, a quantitative assessment of gait improvement in response to TMS therapy in ataxia, as well as neurophysiological evidence in support of modification of cerebellar-cortical interaction that may underlie some of the improvements.

Figure 1. Sagittal view of the patient’s brain as depicted by anatomical MRI

Of note, the presented MRI was obtained in 2004, approximately eight years prior to the present trial. Given the progressive nature of this illness, it is expected that a more recent MRI scan would more accurately illustrate the current structure of the patient’s brain.

Figure 2. Patient performance in a tracing task

The patient’s performance was evaluated before (day 1) (a), midway (day 10) (b) and in the last week of the rTMS intervention (day 21) (c). The patient was instructed to draw a line within the figure without touching any edges. It can be observed that the patient committed less errors after the intervention.

Figure 3. Kinematics and neurophysiological measures acquired before and after the TMS therapy

Panel A demonstrates improvements in standing posture control as evidence by a reduction in the area of postural sway immediately following TMS therapy (b) as compared to baseline (a). These improvements were preserved six months following the trial (c). Panel B demonstrates more rhythmic patterns of lower right leg antagonistic muscle coordination immediately following the TMS therapy (b) and at six months after the therapy (c) as compared to baseline (a). Panel C demonstrates reduction of cerebellar inhibition for the interstimulus intervals of 5-7 ms in the right FDI immediately after TMS therapy (white bars), and at six months after therapy (black bars, tested at the interstimulus interval of 5ms) as compared to baseline (gray bars). Error bars indicate the standard error of the mean and asterisks indicate p<0.001.