Diffusion tensor MRI changes in cerebellar structures of patients with familial essential tremor

Abstract

Neuroimaging evidence of microstructural changes consistent with neurodegeneration was found in the dentate nucleus (DN) and SCP of patients with familial essential tremor. This suggests that neurodegenerative pathology of cerebellar structures may play a role in essential tremor. Further studies are needed to assess the role of fractional anisotropy and mean diffusivity changes in DN and SCP in the differential diagnosis of essential tremor and Parkinson disease, which may present similar clinical signs at the onset of disease.

White matter measures correlate with essential tremor severity—A pilot diffusion tensor imaging study

“…Importantly, areas that correlate with objective tremor measures extend to the midbrain, specifically areas around the cerebral peduncles and red nucleus thus including the WM within dentate‐rubro‐olivary pathway (Guillain‐Mollaret triangle), which is considered a tremorgenic loop (Murdoch, Shah, & Jampana, 2016). These findings are consistent with previous studies showing abnormalities in DTI parameters directly within red nucleus (Jia et al., 2011), in retrorubral WM (Shin, Han, Kim, & Lee, 2008) and the Guillain‐Mollaret triangle (Nicoletti et al., 2010) in ET patients. However, no correlation with tremor clinical parameters was reported in these studies (Jia et al., 2011; Nicoletti et al., 2010; Shin et al., 2008).…”

“…These findings are consistent with previous studies showing abnormalities in DTI parameters directly within red nucleus (Jia et al., 2011), in retrorubral WM (Shin, Han, Kim, & Lee, 2008) and the Guillain‐Mollaret triangle (Nicoletti et al., 2010) in ET patients. However, no correlation with tremor clinical parameters was reported in these studies (Jia et al., 2011; Nicoletti et al., 2010; Shin et al., 2008). Our data show a unique correlation of CST changes exclusively with combined TremScore but not with frequency or FTM scale.…”

“…Previous DTI studies in ET confirmed an involvement of the CTC (Jia, Jia‐lin, Qin, Qing, & Yan, 2011; Klein et al., 2011; Nicoletti et al., 2010; Saini et al., 2012) but also of areas outside the “tremor network” (Klein et al., 2011; Saini et al., 2012) when a whole‐brain DTI analysis using tract‐based spatial statistics (TBSS) (Smith et al., 2006) was applied. The areas outside CTC were linked to nonmotor ET symptoms (Benito‐León et al., 2017; Bhalsing et al., 2014, 2015), which provides further evidence for the pathophysiological complexity of ET.…”

“…The widespread and variable WM alterations in ET (Jia et al., 2011; Klein et al., 2011; Nicoletti et al., 2010; Saini et al., 2012) shown in prior studies emphasize the need to further investigate the correlation of WM microstructure changes with motor signs in ET and to identify potential morphological markers of tremor severity. Identifying the relevant WM areas responsible for motor and nonmotor signs in ET would help explain the variable pharmacotherapy response in ET (Hedera, Cibulčík, & Davis, 2013) and potentially contribute to the development of reliable measures of therapeutic interventions (Ondo, 2016).…”

“…Identifying the relevant WM areas responsible for motor and nonmotor signs in ET would help explain the variable pharmacotherapy response in ET (Hedera, Cibulčík, & Davis, 2013) and potentially contribute to the development of reliable measures of therapeutic interventions (Ondo, 2016). Several DTI studies (Klein et al., 2011; Nicoletti et al., 2010; Pelzer et al., 2017; Saini et al., 2012) utilized clinical rating scales (e.g., Fahn‐Tolosa‐Marin [FTM] and Bain scales) as a measure of tremor severity; however, only two studies found a correlation between the FTM score and frontoparietal WM microstructure (Klein et al., 2011; Pelzer et al., 2017). The lower inter‐rater reliability and the subjective nature of the clinical rating scales (Elble et al., 2013) can be mitigated by objective accelerometry measures (i.e., the tremor frequency and amplitude), which may provide a more accurate representation of the disease pathophysiological features.…”