180 research outputs found

    Future Developments in Clinical MEG and Its Combination with nTMS

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    Development of clinical MEG will provide biomarkers of neurodegenerative disorders by producing functional and effective connectivity measures within and between distinct functional brain areas. It is highly probable that neurodegenerative disorders damage these connections early in their course and detection of such changes will be feasible with sophisticated signal analysis of MEG data. Combining MEG and nTMS has already proven to be valuable in clinical evaluations. Such combinations will assist us in understanding the complex brain networks and the effective connectivity within them both in the healthy and diseased brains.Peer reviewe

    Acute Phase Response in Patients With Uncomplicated and Complicated Endoscopic Retrogradic Cholangiopancreaticography

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    Acute phase response after endoscopic retrogradic cholangiopancreaticography (ERCP) was studied in 42 patients with suspected pancreatic or biliary diseases. In uncomplicated cases acute phase response determined by serum C-reactive protein levels was rare and did not parallel the serum amylase or lipase levels. In three of the these 42 patients, post-ERCP pancreatitis developed and CRP levels elevated sharply and paralleled the degree of pancreatitis. Six additional patients outside of this prospective study with post-ERCP-pancreatitis and daily CRP determinations were used to determine the CRP-response curve in post-ERCP pancreatitis

    Navigated transcranial magnetic stimulation in clinical practice and research

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    Navigated transcranial magnetic stimulation (nTMS) enables precise targeting of the induced electric field to selected cortical targets found by alignment of the head with a 3-D model of the subject’s brain. This is particularly important in studies of patients as some diseases, such as brain tumors, may modify the brain anatomy and function so that the external skull landmarks are not any more aligned with the brain structures. Comparison with the preoperative nTMS and intraoperative direct electrical cortical stimulation (DECS) localization of hand muscle cortical representations has given distances of 3-12 mm between the two methods. Preoperative nTMS mapping is associated with smaller craniotomies and more extensive resections of tumors. Mapping of speech areas with nTMS during videoed object naming is less specific but more sensitive than DECS and produces reliable “negative” maps: if speech nTMS does not find an active area from the area to be resected, DECS findings are highly improbable as well. The first study of clinical impact infers that speech nTMS is associated with smaller craniotomies and less postoperative speech dysfunctions. Good understanding of the relation of nTMS activation sites with those obtained by DECS adds attractivity of the use of nTMS also in the basic research of brain functions.Peer reviewe

    Increasing the frequency of peripheral component in paired associative stimulation strengthens its efficacy

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    Paired associative stimulation (PAS), a combination of transcranial magnetic stimulation (TMS) with peripheral nerve stimulation (PNS), is emerging as a promising tool for alleviation of motor deficits in neurological disorders. The effectiveness and feasibility of PAS protocols are essential for their use in clinical practice. Plasticity induction by conventional PAS can be variable and unstable. Protocols effective in challenging clinical conditions are needed. We have shown previously that PAS employing 50 Hz PNS enhances motor performance in chronic spinal cord injury patients and induces robust motor-evoked potential (MEP) potentiation in healthy subjects. Here we investigated whether the effectiveness of PAS can be further enhanced. Potentiation of MEPs up to 60 minutes after PAS with PNS frequencies of 25, 50, and 100 Hz was tested in healthy subjects. PAS with 100 Hz PNS was more effective than 50 (P = 0.009) and 25 Hz (P = 0.016) protocols. Moreover, when administered for 3 days, PAS with 100 Hz led to significant MEP potentiation on the 3rd day (P = 0.043) even when the TMS target was selected suboptimally (modelling cases where finding an optimal site for TMS is problematic due to a neurological disease). PAS with 100 Hz PNS is thus effective and feasible for clinical applications.Peer reviewe

    Acute Fulminant Pancreatitis: Debridement or Formal Resection of the Pancreas

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    During the ten year period from 1980 to 1989, 51 patients were treated at Oulu University Central Hospital for fulminant acute pancreatitis. Five were in a moribund state on admission and died shortly afterwards, 6 were treated conservatively and survived, and 40 were operated on, 17 by primary pancreatic resection and 23 by debridement of the peripancreatic area. Mortality rates were 53 per cent for the resection group and for the debridement group 22 per cent

    Adenoma of the Papillae of Vater. Report of Eleven Cases

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    Eleven patients with a preoperative diagnosis of adenoma of the papillae of Vater were followed up during the fifteen-year period from 1984 till 1998 in the Oulu University Hospital. Seven patients were treated primarily by transduodenal excision without any recurrences so far. One of these seven patients was found to have adenocarcinoma in a histological examination

    Modulation of sensory cortical activity by deep brain stimulation in advanced Parkinson's disease

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    Despite optimal oral drug treatment, about 90% of patients with Parkinson's disease develop motor fluctuation and dyskinesia within 5-10 years from the diagnosis. Moreover, the patients show non-motor symptoms in different sensory domains. Bilateral deep brain stimulation (DBS) applied to the subthalamic nucleus is considered the most effective treatment in advanced Parkinson's disease, and it has been suggested to affect sensorimotor modulation and relate to motor improvement in patients. However, observations on the relationship between sensorimotor activity and clinical improvement have remained sparse. Here, we studied the somatosensory evoked magnetic fields in 13 right-handed patients with advanced Parkinson's disease before and 7 months after stimulator implantation. Somatosensory processing was addressed with magnetoencephalography during alternated median nerve stimulation at both wrists. The strengths and the latencies of the similar to 60-ms responses at the contralateral primary somatosensory cortices were highly variable but detectable and reliably localized in all patients. The response strengths did not differ between preoperative and postoperative DBSON measurements. The change in the response strength between preoperative and postoperative condition in the dominant left hemisphere of our right-handed patients correlated with the alleviation of their motor symptoms (p = .04). However, the result did not survive correction for multiple comparisons. Magnetoencephalography appears an effective tool to explore non-motor effects in patients with Parkinson's disease, and it may help in understanding the neurophysiological basis of DBS. However, the high interindividual variability in the somatosensory responses and poor tolerability of DBSOFF condition warrants larger patient groups and measurements also in non-medicated patients.Peer reviewe

    Neural mechanisms underlying word- and phrase-level morphological parsing

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    How is morphological and morphosyntactic information processed during sentence reading? Are the neural mechanisms underlying word- and phrase-level combinatorial processing overlapping or distinct? Here, electroencephalography (EEG) and magnetoencephalography (MEG) responses were recorded simultaneously during silent reading of Finnish sentences. The experimental conditions included 1) well-formed grammatical sentences (correct condition), 2) sentences containing morphosyntactic violations (adjective–noun number agreement violations), 3) morphological violations (incorrect stem allomorph and inflectional suffix combination), and 4) combined violations, containing both morphosyntactic and morphological violations. Signal space and source modeling results showed that morphosyntactic violations elicited a left anterior negativity effect, generated particularly in the left inferior frontal area. Morphological violations elicited a widespread negativity, resembling the N400. The neural sources of this negativity were localized most prominently to the right temporal cortical networks. Furthermore, all violations elicited P600 effects with similar widespread bilateral fronto-temporal neural generators that did not differ between morphosyntactic and morphological conditions. Our findings suggest at least partially distinct subnetworks in the fronto-temporal cortices for morphological and morphosyntactic parsing during the earlier stages of processes (∌400 ms post stimulus onset) and shared neural generators for the later processing stages.Peer reviewe

    Effects of Long-Term Paired Associative Stimulation on Strength of Leg Muscles and Walking in Chronic Tetraplegia : A Proof-of-Concept Pilot Study

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    Recovery of lower-limb function after spinal cord injury (SCI) is dependent on the extent of remaining neural transmission in the corticospinal pathway. The aim of this proof-of-concept pilot study was to explore the effects of long-term paired associative stimulation (PAS) on leg muscle strength and walking in people with SCI. Five individuals with traumatic incomplete chronic tetraplegia (>34 months post-injury, motor incomplete, 3 females, mean age 60 years) with no contraindications to transcranial magnetic stimulation (TMS) received PAS to one or both legs for 2 months (28 sessions in total, 5 times a week for the first 2 weeks and 3 times a week thereafter). The participants were evaluated with the Manual Muscle Test (MMT), AIS motor and sensory examination, Modified Asworth Scale (MAS), and the Spinal Cord Independence Measure (SCIM) prior to the intervention, after 1 and 2 months of PAS, and after a 1-month follow-up. The study was registered at (NCT03459885). During the intervention, MMT scores and AIS motor scores increased significantly (p = 0.014 and p = 0.033, respectively). Improvements were stable in follow-up. AIS sensory scores, MAS, and SCIM were not modified significantly. MMT score prior to intervention was a good predictor of changes in walking speed (Radj2 = 0.962). The results of this proof-of-concept pilot study justify a larger trial on the effect of long-term PAS on leg muscle strength and walking in people with chronic incomplete SCI.Peer reviewe
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