Table. 2.1.
Functional MRI studies in PD-FOG - Task-Based fMRI studies.
| Authors (Year) | Participants (years) (mean age±SD) | Technique | Outcome measures | Imaging findings | Clinical correlation |
|---|---|---|---|---|---|
| Shine et al. (2011) | 1 PD-FOG | SPM (event related design) | Activations using virtual-reality walking task | During walking: Lower BOLD response in SMC and anterior cerebellum During dual-task walking: Higher BOLD response in DLPFC, ventrolateral prefrontal cortex, pre-SMA and posterior parietal regions. During the episodes of freezing: Activation of pre-SMA, motor cortices, DLPFC, ventrolateral prefrontal cortex, and posterior parietal region. | Not performed |
| Snijders et al. (2011) | 12 PD-FOG (59±9) 12 PD-nFOG (63±7) 21 HS (57±9) | SPM (event related design) Whole brain analysis and ROI on bilateral superior frontal gyrus, superior parietal lobule, right ACC, left putamen, and MLR | Activations during motor imagery of walking | Higher BOLD response in MLR and lower BOLD response in cingulate, SMA and right superior parietal lobule | Between MLR activity and FOG-Q, disease duration |
| Shine et al. (2013a) | 18 PD-FOG (67±8) | SPM (event-related block design) ROI on precentral sulcus, dorsal premotor area, dorsal caudal, putamen, DLPFC, posterior parietal cortex, caudate anterior insula, ACC, medial prefrontal cortex, ventral striatum, Globus pallidus, STN, anterior thalamus, MLR | Activations during virtual reality task of using the foot pedals to control walking | Higher BOLD response in fronto-parietal and insula Lower BOLD response in SMC, caudate, thalamus, and Globus pallidus internus Higher BOLD response in DLPFC, posterior parietal cortex, and MLR Lower BOLD response in putamen, right dorsal premotor, caudate, medial prefrontal cortex, left anterior insula, ventral striatum, Globus pallidus internus, anterior thalamus and bilateral subthalamic nucleus. | Between activity in sensorimotor regions, frontoparietal cortical regions and FOG-Q |
| Shine et al. (2013b) | 14 PD-FOG (63±7) 15 PD-nFOG (63±8) | SPM (event related design) Whole brain analysis and ROI on bilateral anterior insula, left superior frontal, bilateral ventral striatum, right pre-SMA | Activations during virtual reality task of direct and indirect cues of walking | Higher BOLD response in DLPFC, posterior parietal cortices, midline pre-SMA, anterior insula, medial temporal lobes and extra-striate visual cortex Lower BOLD response in anterior insula, ventral striatum, left STN and SMA Lower BOLD response within the anterior insula, ventral striatum, left STN | Not performed |
| Shine et al. (2013c) | 10 PD-FOG (67±6) | ||||
| 10 PD-nFOG (66±6) | SPM (Boxcar) SPM (ICA) | Activations during direct and indirect cues of walking FC during direct and indirect cues of walking | During task performances higher BOLD response in left cognitive control network and ventral attention network Functional decoupling between basal ganglia and cognitive control network | Not performed | |
| Vercruysse et al. (2014) | 16 PD-FOG (66±7) 16 PD-nFOG (67±5) 16 HS (67±6) | SPM (event related design) ROI on putamen, caudate nucleus, STN, pallidum, PPN, and MLR | Activations during bimanual finger movements | During successful movement: Lower BOLD in DLPFC; higher BOLD response in dorsal putamen, pallidum and STN During motor blocks: higher BOLD in right SMC, dorsal premotor cortex, left prefrontal cortex; lower BOLD in bilateral pallidum and putamen Higher BOLD response in bilateral STN, dorsal putamen, pallidum. | Not performed |
| Peterson et al. (2014) | 9 PD-FOG (67±7) 9 PD-nFOG (63±9) | Brain Voyager (event related design) ROI on SMA, putamen, Globus pallidus interna, MLR, and CLR | Activations during imagined walking and standing | During imagined standing: lower BOLD response in the CLR During imagined walking: lower BOLD in right Globus pallidus | Not performed |
| Hoorn et al. (2014) | 7 PD-FOG (62.1±9.5) 15 PD-nFOG (60.9±12.1) 15 HS (60.5±6.2) | SPM (block design) Psychophysiological interactions (Seed on motion sensitive area right V5) | Activations using effects of optic flow FC using effects of optic flow | Lower BOLD response in dorsal occipito-parietal and pre-SMA | No correlation |
| Gilat et al. (2015) | 17 PD-FOG (67±6) 10 PD-nFOG (65±4) | SPM (event related design) ROI on caudate nucleus, putamen, ventral striatum, MLR, Globus pallidus interna, STN, CLR seed on caudate nucleus, putamen, ventral striatum, MLR, Globus pallidus internus, STN, bilateral CLR) | Activations during virtual reality of simple walking and turning FC during virtual reality of walking and turning | During turning: Higher BOLD response in visual cortex and inferior frontal region During turning: Higher FC in MLR and Globus pallidus | Not performed |
| Agosta et al. (2017) | 13 PD-FOG (64±7) | SPM (block design) | Activations during action observation training and landscape task | During action observation training: Higher BOLD response in fronto-parietal areas | |
| During Landscape: Lower BOLD response in left postcentral gyrus, inferior parietal gyri, right Rolandic operculum and supramarginal gyrus | Not performed | ||||
| Martens et al. (2018) | 41 PD-FOG (67±6) | SPM (epoch related design) Seed on primary motor cortex, SMA, cerebellum, ACC, DLPFC, posterior parietal cortex, medial prefrontal cortex, anterior insula, amygdala | FC during virtual reality task of normal foot tapping | Higher FC between limbic network and ventral striatum Lower FC between striatum -motor and cognitive networks | No correlation |
| Myers et al. (2018) | 13 PD-FOG (65±10) 24 PD-nFOG (66±8) | Brain Voyager (event related design) ROI on regions of SMN, cerebellar regions associated with SMN, and M1 and S1 cortical regions | Activations during imaginary walking task | Lower BOLD response in cerebellum, primary motor and primary sensory cortices | Not performed |
| Nackaerts et al. (2018) | 10 PD-FOG (67±10) 27 PD-nFOG (63±7) | SPM (block design) ROI: extrastriate visual cortex, superior parietal lobule, primary motor cortex, left SMA and right cerebellar lobule VI Dynamic casual modeling (Seed on extrastriate visual cortex, superior parietal lobule, primary motor cortex, left SMA and right cerebellar lobule VI) | Activations during visually cued and uncued handwriting FC during visually cued and uncued handwriting task | Higher BOLD response in visual cortex Weak coupling strength between left extrastriate visual cortex and left superior parietal lobule; left superior parietal lobule-right superior parietal lobule; left dorsal premotor cortex-left SMA; left dorsal premotor cortex-left primary motor cortex | Between effective connectivity and handwriting quality |
| Matar et al. (2019) | 19 PD-FOG (65±6) | SPM (event related design) SPM (seed on STN and auditory cortex) | Activations during virtual reality task using foot pedals to navigate a series of doorways FC during virtual reality task using foot pedals to navigate a series of doorways | Lower BOLD response in pre-SMA Higher FC between pre-SMA and STN | Correlation between functional connectivity and delay in footstep. |
PD-FOG: Parkinson's disease patients with freezing of gait; PD-nFOG: Parkinson's disease patients without freezing of gait; HS: healthy controls; BOLD = Blood oxygenated level dependent signal; SMA: supplementary motor area; FDLPFC: dorsolateral prefrontal cortex; FOG-Q: Freezing of Gait Questionnaire; ROI: Region of interest; SMC: supplementary motor complex; ACC: anterior cingulate cortex; MLR: mesencephalic locomotor region; STN: subthalamic nucleus; ICA: Independent component analysis; FC: Functional connectivity; PPN: pedunculopontine nucleus; CLR: cerebellar locomotor region.
FOG-Q represents severity of freezing of gait (FOG)
*NA: not available