Stereotactic radiosurgery for IDH wild type glioblastoma: an international,multicenter study

Journal of Neuro-Oncology - Isocitrate dehydrogenase (IDH) mutation status is recommended used for diagnosis and prognostication of glioblastoma patients. We studied efficacy and safety of...     

Stereotactic radiosurgery versus active surveillance for incidental,convexity meningiomas: a matched cohort analysis from the IMPASSE study

Journal of Neuro-Oncology - The optimal treatment strategy of asymptomatic, convexity meningiomas, remains unclear. The purpose of this study was to define the safety and efficacy of stereotactic...     

Walking in postpoliomyelitis syndrome: the relationships between time-scored tests, walking in daily life and perceived mobility problems.

OBJECTIVE: To compare walking test results with walking in daily life, and to investigate the relationships between walking tests, walking activity in daily life, and perceived mobility problems in patients with post-poliomyelitis syndrome. SUBJECTS: Twenty-four ambulant patients with post-poliomyelitis syndrome. METHODS: Walking tests were performed at self-preferred and maximal speed. Walking activity was measured with an ambulatory activity monitor. Heart rate, step cadence and walking speed in the test and in daily life were compared. Walking speed in daily life was represented by the intensity of walking. Perceived mobility problems were assessed with the Nottingham Health Profile. RESULTS: Heart rate during walking was lower in the test at self-preferred speed than in daily life (mean difference: 11.3+/-10.4; p=0.001). Self-preferred walking speed in the test and in daily life correlated significantly (r=0.55; p=0.04). In a sub-group with a test performance below the median value, test performance correlated significantly with walking activity. No significant correlation was found between perceived mobility problems and walking activity. CONCLUSION: Walking in daily life may be more demanding than walking under standardized conditions. Patients with post-poliomyelitis syndrome with the lowest test performance walked less in daily life. Patients do not necessarily match their activity pattern to their perceived mobility problems.     

Validity of accelerometry in assessing the duration of the sit-to-stand movement

Accelerometry is frequently used in movement analysis to assess body postures and motions. Here, we assessed the validity of ambulatory accelerometric measurement of the sit-to-stand (STS) movement duration. We compared accelerometric and opto-electronic assessment of the STS movement duration under four conditions (comfortable, slow, fast movement and exaggerated trunk flexion) with six healthy subjects and six subjects with stroke who performed movements six times under each condition. Accelerometric and opto-electronic data of STS movement duration were strongly related (r = 0.98). Accelerometry showed a fixed bias of 0.07 s (95% CI 0.008, 0.141) in healthy subjects and 0.32 s (95% CI 0.223, 0.422) in stroke subjects. In healthy subjects, a significant negative proportional bias of 0.1 was detected (95% CI -0.160, -0.032). Accelerometry showed discriminative validity in comparing stroke subjects to healthy subjects, and in comparing speed conditions. Our results indicate that accelerometry can provide valid data on the STS movement duration, furthermore during its use additional information on the STS movement, such as balance control, can be recorded.     

Motor unit characteristics in healthy subjects and those with postpoliomyelitis syndrome: a high-density surface EMG study

The purpose of this study was to identify optimal ways to detect neurogenic changes with high-density surface electromyography (HD-sEMG). For this purpose, we searched for the variables that most clearly discriminated between postpoliomyelitis and healthy subjects. We obtained HD-sEMG from the quadriceps muscle at different force levels in nine subjects with postpoliomyelitis syndrome and in matched healthy controls. Single motor unit action potentials (MUAPs), extracted from the HD-sEMG signal and the raw signal itself, were analyzed. Areas under the curve of the extracted MUAP waveform, indicating motor unit size, perfectly separated both groups. Raw signal analysis showed significant differences between groups for the monopolarly recorded amplitude up to 60% of maximal force and for the level of interference at higher force levels (40-100% force). We conclude that with HD-sEMG it is possible to detect neurogenic motor unit changes noninvasively, both by analysis of the raw signal itself and by analysis of extracted single MUAPs. The diagnostic yield of the single MUAP analysis is clearly higher. These findings point toward applications for clinical practice and invite further studies exploring the diagnostic value of HD-sEMG.     

Stereotactic radiosurgery versus active surveillance for asymptomatic,skull-based meningiomas: an international,multicenter matched cohort study

Journal of Neuro-Oncology - The optimal management of asymptomatic, skull-based meningiomas is not well defined. The aim of this study is to compare the imaging and clinical outcomes of patients...     

Missense PANK2 mutation without "eye of the tiger" sign: MR findings in a large group of patients with pantothenate kinase-associated neurodegeneration (PKAN)

Purpose:

To present some unusual MR findings in a group of patients from the south‐west of the Dominican Republic suffering from Pantothenate Kinase Associated Neurodegeneration (PKAN).

Materials and Methods:

Twenty patients and one preclinical case homozygous for the PANK2 mutation, 13 heterozygous gene carriers and 14 healthy volunteers were scanned prospectively using a 3 Tesla system.

Results:

All patients showed the typical signal reduction within the globus pallidus and the substantia nigra. A surprising finding was the absence of the bright spot (“tiger's eye”) in the medial part of the pallidum in 6 patients, but not in the preclinical case. Both fractional anisotropy (FA) and mean diffusivity (MD) were increased with high significance in the globus pallidus, whereas a reduction of FA in the anterior parts of the internal capsule was accompanied by an elevation of MD.

Conclusion:

Our findings support the hypothesis that the absence of the “tiger's eye” in PKAN might be secondary, probably caused by an increased accumulation of iron. This could artificially increase FA and MD values and change fiber tracking results. Except for the fronto‐basal tracts, white matter was preserved well. This encouraging finding might support efforts to develop further therapeutic strategies in this devastating dystonia. J. Magn. Reson. Imaging 2012;35:788–794. © 2011 Wiley Periodicals, Inc.     

MRI radiomics in the prediction of the volumetric response in meningiomas after gamma knife radiosurgery

Journal of Neuro-Oncology - Glioma is the most prevalent primary intracranial tumor globally. WDR34, a member of the WDR superfamily with five WD40 repeats, is involved in the pathogenesis of...     

Nitric oxide modulates neuromuscular transmission during hypoxia in rat diaphragm

Hypoxia impairs neuromuscular transmission in the rat diaphragm. In previous studies, we have shown that nitric oxide (NO) plays a role in force modulation of the diaphragm under hypoxic conditions. The role of NO, a neurotransmitter, on neurotransmission in skeletal muscle under hypoxic conditions is unknown. The effects of the NO synthase (NOS) inhibitor nomega-nitro-L-arginine (L-NNA, 1 mM) and the NO donor spermine NONOate (Sp-NO, 1 mM) were evaluated on neurotransmission failure during nonfatiguing and fatiguing contractions of the rat diaphragm under hypoxic (PO2 approximately 5.8 kPa) and hyperoxic conditions (PO2 approximately 64.0 kPa). Hypoxia impaired force generated by both muscle stimulation at 40 HZ (P40M) and by nerve stimulation at 40 HZ (P40N). The effect of hypoxia in the latter was more pronounced. L-NNA increased P40N whereas Sp-NO decreased P40N during hypoxia. In contrast, neither L-NNA nor Sp-NO affected P40N during hyperoxia. L-NNA only slightly reduced neurotransmission failure during fatiguing contractions under hyperoxic conditions. Consequently, neurotransmission failure assessed by comparing force loss during repetitive nerve simulation and superimposed direct muscle stimulation was more pronounced in hypoxia, which was alleviated by L-NNA and aggravated by Sp-NO. These data provide insight in the underlying mechanisms of hypoxia-induced neurotransmission failure. This is important as respiratory muscle failure may result from hypoxia in vivo.