The dentato-rubro-thalamic tract as the potential common deep brain stimulation target for tremor of various origin: an observational case series

Abstract

Introduction Deep brain stimulation alleviates tremor of various origins. The dentato-rubro-thalamic tract (DRT) has been suspected as a common tremor-reducing structure. Statistical evidence has not been obtained. We here report the results of an uncontrolled case series of patients with refractory tremor who underwent deep brain stimulation under tractographic assistance. Methods A total of 36 patients were enrolled (essential tremor (17), Parkinson's tremor (8), multiple sclerosis (7), dystonic head tremor (3), tardive dystonia (1)) and received 62 DBS electrodes (26 bilateral; 10 unilateral). Preoperatively, diffusion tensor magnetic resonance imaging sequences were acquired together with high-resolution anatomical T1W and T2W sequences. The DRT was individually tracked and used as a direct thalamic or subthalamic target. Intraoperative tremor reduction was graded on a 4-point scale (0 = no tremor reduction to 3 = full tremor control) and recorded together with the current amplitude, respectively. Stimulation point coordinates were recorded and compared to DRT. The relation of the current amplitude needed to reduce tremor was expressed as TiCR (tremor improvement per current ratio). Results Stimulation points of 241 were available for analysis. A total of 68 trajectories were tested (62 dB leads, 1.1 trajectories tested per implanted lead). Tremor improvement was significantly decreasing (p < 0.01) if the distance to both the border and the center of the DRT was increasing. On the initial trajectory, 56 leads (90.3%) were finally placed. Long-term outcomes were not part of this analysis. Discussion Tremor of various origins was acutely alleviated at different points along the DRT fiber tract (above and below the MCP plane) despite different tremor diseases. DRT is potentially a common tremor-reducing structure. Individual targeting helps to reduce brain penetrating tracts. TiCR characterizes stimulation efficacy and might help to identify an optimal stimulation point.Keywords Deep brain stimulation . DRT . DRTT . Brain . Diffusion tensor magnetic resonance imaging . MRI . Parkinson's disease . Tremor Bastian Sajonz contributed equally to this work.

Neuromodulation of the subthalamic nucleus in Parkinson’s disease: the effect of fiber tract stimulation on tremor control

“…Accordingly, the limitation of not being able to accurately delineate the white matter tracts in dense areas of crossing, kissing, or branching fibers was prevented. In accordance with groups that used P-FT [1,9,35], we were able to show the tract's decussation instead of ipsilateral tracts resulted from D-FT [10][11][12][13][14][15]19]. In fact, studies comparing P-FT and D-FT showed higher anatomical precision using P-FT not only with tracking the DRT but also other white matter fibers such as the corticospinal tract and fornix [8,18,38].…”

“…Two studies investigated systematically the antitremor effect of DRT neuromodulation on Parkinsonian tremor to date. Endpoints of these case series studies were tremor reduction either during 14 days postoperatively or immediately intraoperatively [14,35]. At this early time point, however, tremor improvement resulting from micro-lesional effects cannot be excluded.…”

Tremor in Multiple Sclerosis—An Overview and Future Perspectives

“…For instance, several clinical studies suggested a correlation between upper limb dystonia symptoms and MS tremor, supporting the idea of the involvement of cerebello-pallido-thalamo-cortical network dysfunction in the pathophysiology of MS tremor [ 23 ]. Moreover, neuroimaging (tractography) data obtained from patients who underwent deep brain stimulation (DBS) for tremor, including those with MS, highlighted the dentato-rubro-thalamic tract as the common stimulation target for DBS [ 24 ]. Recently, structural and functional magnetic resonance imaging studies revealed the involvement of cerebello-thalamo-cortical pathways in the generation of MS tremor [ 25 , 26 ].…”

Injury of the Dentato-Rubro-Thalamic Tract in a Patient with Thalamic Infarct

“…The DRTT, which originates from the dentate nucleus in the cerebellum and terminates in the contralateral ventrolateral (VL) nucleus of the thalamus, is involved in movement control [2]. Therefore, abnormal movement such as ataxia can occur when the DRTT is injured [3][4][5][6][7][8][9][10][11][12]. In this case study, this patient showed severe dysmetria in his right hand and moderate ataxic gait.…”