Abnormal beta power is a hallmark of explicit movement control in functional movement disorders.

OBJECTIVE: To determine whether sensorimotor beta-frequency oscillatory power is raised during motor preparation in patients with functional movement disorders (FMD) and could therefore be a marker of abnormal "body-focused" attention. METHODS: We analyzed motor performance and beta-frequency cortical oscillations during a precued choice reaction time (RT) task with varying cue validity (50% or 95% congruence between preparation and go cues). We compared 21 patients with FMD with 13 healthy controls (HCs). RESULTS: In HCs, highly predictive cues were associated with faster RT and beta desynchronization in the contralateral hemisphere (contralateral slope -0.045 [95% confidence interval (CI) -0.057 to -0.033] vs ipsilateral -0.033 [95% CI -0.046 to -0.021], p < 0.001) and with a tendency for reaching lower contralateral end-of-preparation beta power (contralateral -0.482 [95% CI -0.827 to -0.137] vs ipsilateral -0.328 [95% CI -0.673 to 0.016], p = 0.069). In contrast, patients with FMD had no improvement in RTs with highly predictive cues and showed an impairment of beta desynchronization and lateralization before movement. CONCLUSIONS: Persistent beta synchronization during motor preparation could reflect abnormal explicit control of movement in FMD. Excessive attention to movement itself rather than the goal might maintain beta synchronization and impair performance

Lateral and Medial Ventral Occipitotemporal Regions Interact During the Recognition of Images Revealed from Noise

Several studies suggest different functional roles for the medial and the lateral sections of the ventral visual cortex in object recognition. Texture and surface information is processed in medial sections, while shape information is processed in lateral sections. This begs the question whether and how these functionally specialized sections interact with each other and with early visual cortex to facilitate object recognition. In the current research, we set out to answer this question. In an fMRI study, 13 subjects viewed and recognized images of objects and animals that were gradually revealed from noise while their brains were being scanned. We applied dynamic causal modeling (DCM) a method to characterize network interactions to determine the modulatory effect of object recognition on a network comprising the primary visual cortex (V1), the lingual gyrus (LG) in medial ventral cortex and the lateral occipital cortex (LO). We found that object recognition modulated the bilateral connectivity between LG and LO. Moreover, the feed-forward connectivity from Vito LG and LO was modulated, while there was no evidence for feedback from these regions to V1 during object recognition. In particular, the interaction between medial and lateral areas supports a framework in which visual recognition of objects is achieved by networked regions that integrate information on image statistics, scene content and shape rather than by a single categorically specialized region within the ventral visual cortex

Anterior temporal atrophy and posterior progression in patients with Parkinson’s disease.

Background: Parkinson's disease (PD) is characterized by specific motor and nonmotor impairments. This suggests that PD is characterized by disease-specific regional cortical atrophy. Given the change of symptoms over time, a concurrent increase in regional atrophy may further be assumed to reflect the dynamic process of disease progression. Methods: In this study we retrospectively collected T1-weighted MRI scans from previous studies performed in our center, enabling the comparison of gray matter atrophy in 77 PD patients with 87 controls using voxel-based morphometry (VBM). This large VBM analysis provided the opportunity to investigate cortical atrophy in relation with disease progression. Results: We found significant PD-related reductions of gray matter density bilaterally in the anterior temporal cortex, the left inferior frontal and left extrastriate visual cortex, independent from normal aging. The anterior temporal cortex did not show major progression, whereas particularly the posterior parts of the lateral temporal cortex and adjacent extrastriate visual cortex occurred at a later stage of disease. Conclusions: Temporal pole atrophy as an early sign of PD is consistent with the PD pathology classification of Braak. The initial anterior temporal atrophy with spread to occipitotemporal and posterior parietal regions may subserve 'emotion-based' sensorimotor transformations and deficits in the visual domain, respectively, which may be regarded as premotor symptoms. © 2014 S. Karger AG, Basel

Visual hallucinations in Parkinson's disease : clinical and fMRI studies

De ziekte van Parkinson (ZvP) is een progressieve hersenaandoening waarbij motorische symptomen als tremor, traagheid en stijfheid op de voorgrond staan. Niet-motorische symptomen, zoals visuele hallucinaties (VH), komen daarnaast veelvuldig voor. Het pathofysiologische mechanisme van VH in de ZvP is nog onbekend. Voorheen werden VH vooral gezien als bijwerking van dopaminerge medicatie, maar inmiddels is duidelijk dat ook ziektegerelateerde processen een belangrijke rol spelen. In dit proefschrift werden mogelijke associaties tussen gestoorde visuele perceptie, verminderde aandacht en VH in de ZvP onderzocht. Parkinsonpatiënten met VH waren trager in het herkennen van plaatjes die tevoorschijn kwamen uit ruis, vergeleken met Parkinsonpatiënten zonder VH en gezonde vrijwilligers. Bovendien scoorden Parkinsonpatiënten met VH inderdaad minder goed op testen van volgehouden aandacht, waarneming van voorwerpen en ruimtelijke waarneming. M.b.v. functionele MRI (fMRI) werden cerebrale activatiepatronen voor en tijdens herkenning van de hierboven beschreven plaatjes die tevoorschijn komen uit ruis onderzocht. Parkinsonpatiënten met VH hadden verminderde activatie van visuele associatiegebieden voordat het beeld werd herkend, vergeleken met Parkinsonpatiënten zonder VH en gezonde vrijwilligers. Deze VH-geassocieerde functionele defecten in Parkinsonpatiënten gingen niet gepaard met volumeverlies van grijze stof, maar zouden wel vooraf kunnen gaan aan deze anatomische veranderingen. Een andere mogelijke oorzaak van de beschreven functionele verschillen is vermindering van de neurotransmitter acetylcholine. Verhoging van acetylcholine zou dan een 'normalisatie' kunnen geven van gestoorde visuele cortex activatie in Parkinsonpatiënten met VH. Tot slot beschrijven wij een model dat kan word­en gebruikt als startpunt voor toekomstig onderzoek naar de pathogenese en behandeling van VH in de ZvP.

Regional Cortical Grey Matter Loss in Parkinson's Disease Without Dementia is Independent from Visual Hallucinations

In our previous functional magnetic resonance imaging study, Parkinson's disease (PD) patients with visual hallucinations (VH) showed reduced activations in ventral/ lateral visual association cortices preceding image recognition, compared with both PD patients without VH and healthy controls. The primary aim of the current study was to investigate whether functional deficits are associated with grey matter volume changes. In addition, possible grey matter differences between all PD patients and healthy controls were assessed. By using 3- Tesla magnetic resonance imaging (MRI) and voxel- based morphometry (VBM), we found no differences between PD patients with (n = 11) and without VH (n = 13). However, grey matter decreases of the bilateral prefrontal and parietal cortex, left anterior superior temporal, and left middle occipital gyrus were found in the total group of PD patients, compared with controls (n = 14). This indicates that previously demonstrated functional deficits in PD patients with VH are not associated with grey matter loss. The strong left parietal reduction in both nondemented patient groups was hemisphere specific and independent of the side of PD symptoms. (C) 2010 Movement Disorder Societ

Visual Object Recognition and Attention in Parkinson's Disease Patients with Visual Hallucinations

Visual hallucinations (VH) are common in Parkinson's disease (PD) and are hypothesized to be due to impaired visual perception and attention deficits. We investigated whether PD patients with VH showed attention deficits a more specific impairment of higher order visual perception or both. Forty-two volunteers participated in this study including 14 PD patients with VH, 14 PD patients without VH and 14 healthy controls (HC), matched for age, gender, education level and for level of executive function. We created movies with images of animals, people, and objects dynamically appearing out of random noise. Time until recognition of the image was recorded. Sustained attention was tested using the Test of Attentional Performance. PD patients with VH recognized all images but were significantly slower in image recognition than both PD patients without VH and HC. PD patients with VH showed decreased sustained attention compared to PD patients without VH who again performed worse than HC. In conclusion, the recognition of objects is intact in PD patients with VH; however, the patients where significantly slower in image recognition than patients without VH and HC, which was not explained by executive dysfunction. Both image recognition speed and sustained attention decline in PD, in amore progressive way if VH start to occur (C) 2008 Movement Disorder Society

Transcutaneous Port for Continuous Duodenal Levodopa/Carbidopa Administration in Parkinson's Disease

Motor fluctuations in Parkinson's disease (PD) can be reduced by intraduodenal infusion of levodopa-carbidopa (Duodopa (R)) via percutaneous endoscopic gastrojejunostomy (PEG). We applied the transcutaneous soft-tissue anchored titanium port (T-port) in 15 PD patients with motor fluctuations; 7 Duodopa-naive (non-PEG), and 8 previously receiving Duodopa (former-PEG). Motor scores (UPDRS-III) and quality of life (QOL, PDQ-8) were assessed at baseline and 6 month follow-up. Six patients had local irritation shortly after implantation, persisting in one patient at 6 month follow-up, which led to explantation. After having finished the protocol, four T-ports were explanted in total. UPDRS-III and PDQ-8 scores improved moderately in the non-PEG patients, but remained similar in the former-PEG users. Two former-PEG users developed polyneuropathy. No obstructions, retractions, or leakages occurred. Technical and hygienic properties of the T-port were preferred by most patients. The T-port seems to be suitable for most PD patients qualifying for Duodopa therapy, although local infection may lead to explantation during longer-term follow-up. (C) 2010 Movement Disorder Societ