Search

Background:Visual perception deficits are a recurrent manifestation in Parkinson's disease (PD). Recently, structural abnormalities of fronto-parietal areas and subcortical regions, implicated in visual stimuli analysis, have been observed in PD patients with cognitive decline and visual hallucinations. The aim of the present study was to investigate the salient aspects of visual perception in cognitively unimpaired PD patients. Methods: Eleven right-handed non-demented right-sided onset PD patients without visuospatial impairment or hallucinations and 11 healthy controls were studied with functional magnetic resonance imaging while performing a specific visuoperceptual/visuospatial paradigm that allowed to highlight the specific process underlying visuospatial judgment. Results: Significant changes in both cortical areas and subcortical regions involved in visual stimuli processing were observed. In particular, PD patients showed a reduced activation for the right insula, left putamen, bilateral caudate, and right hippocampus, as well as an over-activation of the right dorso-lateral prefrontal and of the posterior parietal cortices, particularly in the right hemisphere. Conclusions:We found that both loss of efficiency and compensatory mechanisms occur in PD patients, providing further insight into the pathophysiological role of the functional alterations of basal ganglia and limbic structures in the impairment of visuoperceptual and visuospatial functions observed in PD. [ABSTRACT FROM AUTHOR]

Motor impairment is the most relevant clinical feature in Parkinson's disease (PD). Functional imaging studies on motor impairment in PD have revealed changes in the cortical motor circuits, with particular involvement of the fronto-striatal network. The aim of this study was to assess brain activations during the performance of three different motor exercises, characterized by progressive complexity, using a functional fMRI multiple block paradigm, in PD patients and matched control subjects. Unlike from single-task comparisons, multi-task comparisons between similar exercises allowed to analyse brain areas involved in motor complexity planning and execution. Our results showed that in the single-task comparisons the involvement of primary and secondary motor areas was observed, consistent with previous findings based on similar paradigms. Most notably, in the multi-task comparisons a greater activation of supplementary motor area and posterior parietal cortex in PD patients, compared with controls, was observed. Furthermore, PD patients, compared with controls, had a lower activation of the basal ganglia and limbic structures, presumably leading to the impairment in the higher levels of motor control, including complexity planning and execution. The findings suggest that in PD patients occur both compensatory mechanisms and loss of efficiency and provide further insight into the pathophysiological role of distinct cortical and subcortical areas in motor dysfunction. [ABSTRACT FROM AUTHOR]

Cerebral maturation is characterized by different age-dependent molecular and cellular processes and follows a different course for grey matter (GM) and white matter (WM). During brain development, a crucial point seems to be represented by the establishment of a hemispheric specialization with the left hemisphere dominant for language and motor control and the right hemisphere dominant for visuospatial processing and attention. Therefore, motor and cognitive development are strongly connected. Atypical motor development and lateralization can be associated with neurodevelopmental disorders, such as Language Disorder, Learning Disorders (Dysgraphia and Dyslexia), Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder. The aim of our research was to investigate the possible effects of intensive motor training on WM plasticity and writing skills in children with Developmental Dysgraphia through a tractography study of the main WM tracts. Considering the effect of training for the Mean Diffusivity (MD) over 18 WM tracts, in 6 collaborating dysgraphic patient MD decrease (-4.3%) and in 3 not. Intensive motor training affects both stimulated and not stimulated WM tracts and showed a double not-specificity: for not stimulated hemilate and for not directly stimulated WM tracts. Intensive motor training improves both some lateralized brain functions and intra- and inter-hemispheric connectivity in our patients with good compliance with motor treatment. Moreover, our findings have shown that WM plasticity improvement concerned cortical areas responsible for both motor and cognitive functions.

Competing Interests: The authors declare no conflict of interest.

Aims and Background: Few clinical data exist concerning normal brain tissue tolerance to re-irradiation. The present study evaluated long-term outcome of 22 recurrent glioblastoma patients re-irradiated with radiosurgery or fractionated stereotactic radiotherapy., Methods: Twenty-two patients were treated with radiosurgery (13, 59%) or fractionated stereotactic radiotherapy (9, 41%) for 24 lesions of recurrent glioblastoma. The male/female ratio was 14:8, median age 55 years (range, 27-81), and median Karnofsky performance status 90 (range, 70-100). The majority of the cases (77%) was in recursive partitioning analysis classes III or IV Radiosurgery or fractionated stereotactic radiotherapy was chosen according to lesion size and location., Results: Median time between primary radiotherapy and re-irradiation was 9 months. Median doses were 17 Gy and 30 Gy, whereas median cumulative normalized total dose was 141 Gy and 98 Gy for radiosurgery and fractionated stereotactic radiotherapy, respectively. All patients submitted to radiosurgery had a cumulative normalized total dose of more than 100 Gy, whereas only a few (44%) of fractionated stereotactic radiotherapy patients had a cumulative normalized total dose exceeding 100 Gy. Median follow-up from re-irradiation was 54 months. At the time of analysis, all patients had died. After re-irradiation, 1 (4%) lesion was in partial remission, 16 (67%) lesions were stable, and the remaining 7 (29%) were in progression. Median duration of response was 6 months, and median survival from re-irradiation 11 months. Three of 13 (23%) patients submitted to radiosurgery developed asymptomatic brain radionecrosis. The cumulative normalized total dose for the 3 patients was 122 Gy, 124 Gy, and 141 Gy, respectively. In one case, the volume of the lesion was large (14 cc), and in the other 2 the interval between the first and second cycle of radiotherapy was short (5 months)., Conclusions: Re-irradiation with radiosurgery and fractionated stereotactic radiotherapy is feasible and effective in recurrent glioblastoma patients. Apart from the importance of an accurate patient selection, cumulative radiotherapy dose and a correct indication for radiosurgery or fractionated stereotactic radiotherapy must be taken into account to avoid brain toxicity.

The authors report two cases of nodular calcium pyrophosphate dihydrate (CPPD) crystal deposition close to the thoracic neural foramen, which caused chronic radiculopathy. Preoperatively, the lesions were interpreted as calcified disc herniations. Both patients underwent surgery in which an extended transfacet pedicle-sparing approach was used. Incision of the posterior longitudinal ligament released soft degenerated material. In both cases, histological examination showed abundant degenerative debris along with CPPD crystals. Spinal CPPD deposition is a comparatively rare disease that almost invariably involves the posterior aspect of the spinal canal, typically the ligamentum flavum. The exceptional foraminal location of the lesions reported here, combined with the surgical findings, indicated that the CPPD crystals were deposited on a laterally herniated disc fragment. A distinctive feature in both cases was the soft consistency of the resected tissue. The consistency of the disc material and the location of the lesion in the axial plane (that is, median compared with lateral) are key factors in determining the optimal surgical approach to thoracic disc herniations. In describing consistency, terms such as "calcified" and "hard" have been used interchangeably in the literature. In the cases reported here, what appeared on computerized tomography and magnetic resonance imaging studies to be densely calcified lesions were shown intraoperatively to be soft herniations. The authors' experience underscores that not all densely calcified herniated discs are hard. Although detection of this discrepancy would have left surgical planning for the lateral disc herniations unchanged, it could have altered planning for centrally or centrolaterally located disc herniations.