Comparison of cognitive impairment in Parkinson disease and essential tremor

ObjectiveTo assess white matter integrity in patients with essential tremor (ET) and Parkinson disease (PD) with moderate to severe motor impairment.MethodsSedated participants with ET (n = 57) or PD (n = 99) underwent diffusion tensor imaging (DTI) and fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity values were computed. White matter tracts were defined using 3 well-described atlases. To determine candidate white matter regions that differ between ET and PD groups, a bootstrapping analysis was applied using the least absolute shrinkage and selection operator. Linear regression was applied to assess magnitude and direction of differences in DTI metrics between ET and PD populations in the candidate regions.ResultsFractional anisotropy values that differentiate ET from PD localize primarily to thalamic and visual-related pathways, while diffusivity differences localized to the cerebellar peduncles. Patients with ET exhibited lower fractional anisotropy values than patients with PD in the lateral geniculate body (p < 0.01), sagittal stratum (p = 0.01), forceps major (p = 0.02), pontine crossing tract (p = 0.03), and retrolenticular internal capsule (p = 0.04). Patients with ET exhibited greater radial diffusivity values than patients with PD in the superior cerebellar peduncle (p < 0.01), middle cerebellar peduncle (p = 0.05), and inferior cerebellar peduncle (p = 0.05).ConclusionsRegionally, distinctive white matter microstructural values in patients with ET localize to the cerebellar peduncles and thalamo-cortical visual pathways. These findings complement recent functional imaging studies in ET but also extend our understanding of putative physiologic features that account for distinctions between ET and PD.

Download Full-text

White matter abnormalities in the corpus callosum with cognitive impairment in Parkinson disease

Neurology ◽

10.1212/wnl.0000000000006646 ◽

2018 ◽

Vol 91 (24) ◽

pp. e2244-e2255 ◽

Cited By ~ 16

Author(s):

Ian O. Bledsoe ◽

Glenn T. Stebbins ◽

Doug Merkitch ◽

Jennifer G. Goldman

Keyword(s):

Cognitive Impairment ◽

White Matter ◽

Corpus Callosum ◽

Parkinson Disease ◽

Information Transfer ◽

Diffusion Tensor ◽

Anterior Segment ◽

Mean Diffusivity ◽

Cognitive Domain ◽

White Matter Abnormalities

ObjectiveTo evaluate microstructural characteristics of the corpus callosum using diffusion tensor imaging (DTI) and their relationships to cognitive impairment in Parkinson disease (PD).MethodsSeventy-five participants with PD and 24 healthy control (HC) participants underwent structural MRI brain scans including DTI sequences and clinical and neuropsychological evaluations. Using Movement Disorder Society criteria, PD participants were classified as having normal cognition (PD-NC, n = 23), mild cognitive impairment (PD-MCI, n = 35), or dementia (PDD, n = 17). Cognitive domain (attention/working memory, executive function, language, memory, visuospatial function) z scores were calculated. DTI scalar values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), were established for 5 callosal segments on a midsagittal plane, single slice using a topographically derived parcellation method. Scalar values were compared among participant groups. Regression analyses were performed on cognitive domain z scores and DTI metrics.ResultsParticipants with PD showed increased AD values in the anterior 3 callosal segments compared to healthy controls. Participants with PDD had significantly increased AD, MD, and RD in the anterior 2 segments compared to participants with PD-NC and most anterior segment compared to participants with PD-MCI. FA values did not differ significantly between participants with PD and participants with HC or among PD cognitive groups. The strongest associations for the DTI metrics and cognitive performance occurred in the most anterior and most posterior callosal segments, and also reflected fronto-striatal and posterior cortical type cognitive deficits, respectively.ConclusionsMicrostructural white matter abnormalities of the corpus callosum, as measured by DTI, may contribute to PD cognitive impairment by disrupting information transfer across interhemispheric and callosal–cortical projections.

Download Full-text

HTRA2 p.G399S in Parkinson disease, essential tremor, and tremulous cervical dystonia

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1503105112 ◽

2015 ◽

Vol 112 (18) ◽

pp. E2268-E2268 ◽

Cited By ~ 10

Author(s):

Charalampos Tzoulis ◽

Tetyana Zayats ◽

Per Morten Knappskog ◽

Bernd Müller ◽

Jan Petter Larsen ◽

...

Keyword(s):

Parkinson Disease ◽

Essential Tremor ◽

Cervical Dystonia

Download Full-text

Gamma Knife Thalamotomy for Parkinson Disease and Essential Tremor: A Prospective Multicenter Study

Neurosurgery ◽

10.1227/neu.0b013e3182350893 ◽

2011 ◽

Vol 70 (3) ◽

pp. 526-536 ◽

Cited By ~ 62

Author(s):

Chihiro Ohye ◽

Yoshinori Higuchi ◽

Toru Shibazaki ◽

Takao Hashimoto ◽

Toru Koyama ◽

...

Keyword(s):

Parkinson Disease ◽

Essential Tremor ◽

Gamma Knife ◽

Rating Scale ◽

Spherical Shape ◽

High Signal ◽

Lateral Part ◽

Thalamic Lesion ◽

Clinical Effects

Abstract BACKGROUND: No prospective study of gamma knife thalamotomy for intractable tremor has previously been reported. Objective: To clarify the safety and optimally effective conditions for performing unilateral gamma knife (GK) thalamotomy for tremors of Parkinson disease (PD) and essential tremor (ET), a systematic postirradiation 24-month follow-up study was conducted at 6 institutions. We present the results of this multicenter collaborative trial. Methods: In total, 72 patients (PD characterized by tremor, n = 59; ET, n = 13) were registered at 6 Japanese institutions. Following our selective thalamotomy procedure, the lateral part of the ventralis intermedius nucleus, 45% of the thalamic length from the anterior tip, was selected as the GK isocenter. A single 130-Gy shot was applied using a 4-mm collimator. Evaluation included neurological examination, magnetic resonance imaging and/or computerized tomography, the unified Parkinson's disease rating scale (UPDRS), electromyography, medication change, and video observations. Results: Final clinical effects were favorable. Of 53 patients who completed 24 months of follow-up, 43 were evaluated as having excellent or good results (81.1%). UPDRS scores showed tremor improvement (parts II and III). Thalamic lesion size fluctuated but converged to either an almost spherical shape (65.6%), a sphere with streaking (23.4%), or an extended high-signal zone (10.9%). No permanent clinical complications were observed. Conclusion: GK thalamotomy is an alternative treatment for intractable tremors of PD as well as for ET. Less invasive intervention may be beneficial to patients.

Download Full-text