Table. 1.2.
Structural MRI studies in PD-FOG - White Matter Studies.
| Authors (Year) | Participants (years) (mean age±SD) | Technique | Outcome measures | Imaging findings | Clinical correlation |
|---|---|---|---|---|---|
| Schweder et al. (2010) | 2 PD-FOG (NA) 8 PD-nFOG (NA) 17 HS (NA) | Tractography (Seed on PPN) | WM connectivity | Higher PPN connectivity with anterior pontine nucleus of the fourth ventricle | Not performed |
| Fling et al. (2013) | 14 PD-FOG (67±5) 12 PD-nFOG (65±7) 15 HS (67±8) | Tractography (Seed on PPN) | WM connectivity | Lower PPN connectivity with cerebellum, thalamus, areas of frontal and prefrontal cortex | No correlation |
| Fling et al. (2014) | 8 PD-FOG (65±6) 7 PD-nFOG (64±6) 14 HS (67±8) | Tractography (ROI-ROI; right STN and SMA; left STN and SMA; right MLR and SMA; left MLR and SMA) | WM connectivity strength | Lower connectivity strength between right STN – SMA | No correlation |
| Peterson et al. (2015) | 13 PD-FOG (65±7) 12 PD-nFOG (66±5) | Tractography (Seed on PPN) | Stride length | Stride length changes within the PPN | Between asymmetry of PPN structural connectivity and dual-task interference |
| Canu et al. (2015) | 35 PD-FOG (68±8) 23 HS (67±8) | TBSS (whole brain skeleton) Tractography (Seed on PPT) | FA, MD, AD, and RD within the skeleton FA, MD, AD, and RD within the PPT | Higher FA Lower MD in motor, frontal, orbitofrontal and parietal areas Higher AD in PPT | No correlation Between AD of PPT and UPDRS-III |
| Vercruysse et al. (2015) | 11 PD-FOG (69±9) 15 PD-nFOG (68±6) 15 HS (68±6) | TBSS (whole brain skeleton) Tractography (Seed on caudate, putamen, pallidum, STN, thalamus, PPN and MCP) | FA, and MD within the skeleton FA and MD within the mask of 7 seeds | Lower FA in cerebellum and SLF; higher MD in anterior part of internal capsule Lower FA in caudate, putamen, pallidum, STN, frontal, motor and sensory areas | Between FA in the left caudate–ACC tract and UPDRS-III Between MD of left striatofrontal tracts and UPRDS-III |
| Youn et al. (2015) | 19 PD-FOG (71±6) 23 PD-nFOG (68±6) 33 HS (70±6) | TBSS (whole brain skeleton) TBSS (Seed on PPN) | FA, and MD within the skeleton FA and MD within the PPN | Higher MD in basal ganglia, thalamus and cerebellum Lower FA; higher MD in bilateral PPN | No correlation Between FA of PPN and FOG-Q |
| Trufanov et al. (2016) | 31 PD-FOG 47 PD-nFOG | Tractography (Seed on ATR, CST, ILF, and SLF) | FA, and MD within the seed | Lower FA; and higher RD along the upper longitudinal fascicles of temporal area | No correlation |
| Wang et al. (2016) | 14 PD-FOG (72±6) 16 PD-nFOG (69±6) 16 HS (69±3) | TBSS (whole brain skeleton) | FA, and MD within the skeleton | Lower FA; higher MD in left cingulum, CC, internal capsule, posterior thalamic radiations, corona radiate, external capsule, sagittal stratum and SLF Higher MD in cerebral peduncles, inferior fronto-occipital fasciculus | Not performed |
| Bharti et al. (2019a) | 15 PD-FOG (71±7) 16 PD-nFOG (66±11) 16 HS (67±8) | TBSS (Seeds on SCP, MCP, and inferior cerebellar peduncle) | FA, and MD in the cerebellar peduncles | Lower FA and higher MD in SCP, and MCP | Between FA, MD of SCP, MCP and FOG-Q |
| Hall et al. (2018) | 26 PD-FOG (64±9)24 PD-nFOG (66.9±5) | Graph theory analysis | Modularity | Higher involvement of frontal and parietal brain areas along with right caudate, thalamus, and hippocampus | No correlation result |
| Pietracupa et al. (2018) | 21 PD-FOG (66±11) 16 PD-nFOG (70±11) 19 HS (67±8) | Tractography (Seeds on CST, SLF, ATR, uncinate fasciculus, cingulum, ILF and CC) | FA, MD, AD, and RD within the seed | WM changes in SLF, uncinate fasciculus, cingulate gyrus and CC | Between several WM bundles and MMSE, FAB, H&Y and HAM-D |
PD-FOG: Parkinson's disease patients with freezing of gait; PD-nFOG: Parkinson's disease patients without freezing of gait; HS: healthy controls; FOG-Q: Freezing of Gait Questionnaire; WM: White matter; PPN: Pedunculopontine nucleus; MLR: Mesencephalic locomotor region; SMA: supplementary motor area; STN: Subthalamic nucleus; TBSS: Tract-Based Spatial Statistics; FA: Fractional anisotropy; MD: Mean diffusivity; AD: Axial diffusivity; RD: Radial diffusivity; PPT: pedunculopontine tract; UPDRS: Unified Parkinson's Disease Rating Scale; SLF: Superior longitudinal fasciculus; MCP: Medial cerebellar peduncle; CC: Corpus callosum; CST: Corticospinal tract; ATR: Anterior thalamic radiation; ILF: Inferior longitudinal fasciculus; MMSE: Mini-mental state examination; H&Y: Hoehn and Yahr scale; HAM-D: Hamilton depression rating scale; SCP: Superior cerebellar peduncle.
FOG-Q represents severity of freezing of gait (FOG)
*NA: not available