Two years' experience of implementing a comprehensive telemedical stroke network comprising in mainly rural region: the Transregional Network for Stroke Intervention with Telemedicine (TRANSIT-Stroke).

BACKGROUND: Telemedicine improves the quality of acute stroke care in rural regions with limited access to specialized stroke care. We report the first 2 years' experience of implementing a comprehensive telemedical stroke network comprising all levels of stroke care in a defined region. METHODS: The TRANSIT-Stroke network covers a mainly rural region in north-western Bavaria (Germany). All hospitals providing acute stroke care in this region participate in TRANSIT-Stroke, including four hospitals with a supra-regional certified stroke unit (SU) care (level III), three of those providing teleconsultation to two hospitals with a regional certified SU (level II) and five hospitals without specialized SU care (level I). For a two-year-period (01/2015 to 12/2016), data of eight of these hospitals were available; 13 evidence-based quality indicators (QIs) related to processes during hospitalisation were evaluated quarterly and compared according to predefined target values between level-I- and level-II/III-hospitals. RESULTS: Overall, 7881 patients were included (mean age 74.6 years ±12.8; 48.4% female). In level-II/III-hospitals adherence of all QIs to predefined targets was high ab initio. In level-I-hospitals, three patterns of QI-development were observed: a) high adherence ab initio (31%), mainly in secondary stroke prevention; b) improvement over time (44%), predominantly related to stroke specific diagnosis and in-hospital organization; c) no clear time trends (25%). Overall, 10 out of 13 QIs reached predefined target values of quality of care at the end of the observation period. CONCLUSION: The implementation of the comprehensive TRANSIT-Stroke network resulted in an improvement of quality of care in level-I-hospitals.

Post-traumatic headache: is it for real? Crossfire debates on headache: pro.

Mild traumatic brain injury is very common in Western societies, affecting approximately 1.8 million individuals in the USA. Even though between 30% and 90% of patients develop post-traumatic headache, post-traumatic headache remains a very controversial disorder. Particularly when it comes to chronic post-traumatic headache following mild closed head injury and headache attributed to whiplash injury. Some experts are disputing its existence as a genuine disorder. Indistinct disease classification, unresolved pathophysiological mechanism, and the role of accident-related legal issues further fuel this controversy. The complex combination of pain and neuropsychological symptoms needs further research in understanding the underlying pathophysiological mechanisms associated with the acute headache following trauma but more so the mechanisms associated with the development of chronic pain in some patients. Investigators should refrain from oversimplifying these complex mechanisms as hysteric exaggeration of everyday complains and from implying greed as motivation for this potentially very disabling disease.

Reorganization of motor execution rather than preparation in poststroke hemiparesis.

BACKGROUND AND PURPOSE: The aim of the present study was to examine movement-related potentials (MRPs) in patients in the "chronic" stage after cortical stroke with recovered hemiparesis compared with healthy control subjects. METHODS: Right index finger MRPs were derived from 12 patients > or =1 year after infarction in the territory of the left middle cerebral artery as well as from 12 control subjects. MRP components were compared between groups. RESULTS: In the patient group, the component directly preceding movement onset (negative slope [NS]) was significantly reduced over the lesioned hemisphere contralateral to the movement. Furthermore, increased motor potentials (MPs) were observed over the contralesional hemisphere during movement execution. No changes in the early MRP (Bereitschaftspotential) reflecting movement preparation were found. CONCLUSIONS: Because the NS is supposed to be generated by the primary motor cortex, the decreased component over the lesioned hemisphere is interpreted to represent impaired contralateral M1 functioning in stroke patients. Contralesional activity has been reported as a probable sign of brain plasticity by functional imaging studies. Our results broaden these findings, giving new insights into the temporal course of movement-related brain activity in recovered cortical stroke patients. The data point to a functional reorganization of motor execution rather than preparation in poststroke hemiparesis.

On the neural basis of focused and divided attention.

Concepts of higher attention functions distinguish focused and divided attention. The present study investigated whether these mental abilities are mediated by common or distinct neural substrates. In a first experiment, 19 healthy subjects were examined with functional brain imaging (fMRI) while they attended to either one or both of two simultaneously presented visual information streams and responded to repetitive stimuli. This experiment resembled a typical examination of these mental functions with the single task demanding focused and the dual task conditions requiring divided attention. Both conditions activated a widespread, mainly right-sided network including dorso- and ventrolateral prefrontal structures, superior and inferior parietal cortex, and anterior cingulate gyrus. Under higher cognitive demands of divided attention, activity in these structures was enhanced and left-sided homologues were recruited. In a second experiment investigating another 17 subjects with almost the same paradigm, it was accounted for that in most dual task investigations of focused and divided attention the single tasks are easier to process than their combined presentation. Therefore, the task difficulty of focused attention tasks was increased. Almost the same activity pattern observed during division of attention was now found during focusing attention. Comparing both attentional states matched for task difficulty, differences were found in visual but not in prefrontal or parietal cortex areas. Our results suggest that focused and divided attention depend on largely overlapping neuronal substrates. Differences in activation patterns, especially in prefrontal and parietal areas, may result from unequal demands on executive control due to disparate processing requirements in typical tasks of focused and divided attention: Easier conditions begin with mainly right-sided activity within the attention network. As conditions become more difficult, left-lateralized homologue areas activate.

Antinociceptive reflex alteration in acute posttraumatic headache following whiplash injury.

Brainstem-mediated antinociceptive inhibitory reflexes of the temporalis muscle were investigated in 82 patients (47 F, 35 M, mean age 28.3 years, SD 9.4) with acute posttraumatic headache (PH) following whiplash injury but without neurological deficits, bone injury of the cervical spine or a combined direct head trauma on average 5 days after the acceleration trauma. Latencies and durations of the early and late exteroceptive suppression (ES1 and ES2) and the interposed EMG burst (IE) of the EMG of the voluntarily contracted right temporalis muscle evoked by ipsilateral stimulation of the second and third branches of the trigeminal nerve were analyzed and compared to a cohort of 82 normal subjects (43 F, 39 M, mean age 27.7 years, SD 7.1). Highly significant reflex alterations were found in patients with PH with a shortening of ES2 duration with delayed onset and premature ending as the primary parameter of this study, a moderate prolongation of ES1 and IE duration and a delayed onset of IE. The latency of ES1 was not significantly changed. These findings indicate that acute PH in whiplash injury is accompanied by abnormal antinociceptive brainstem reflexes. We conclude that the abnormality of the trigeminal inhibitory temporalis reflex is based on a transient dysfunction of the brainstem-mediated reflex circuit mainly of the late polysynaptic pathways. The reflex abnormalities are considered as a neurophysiological correlate of the posttraumatic (cervico)-cephalic pain syndrome. They point to an altered central pain control in acute PH due to whiplash injury.

Recovery of movement-related potentials in the temporal course after prefrontal traumatic brain injury: a follow-up study.

OBJECTIVE: The movement-related potential (MRP) is an EEG measure related to self-initiated movements, consisting of the Bereitschaftspotential (BP), the negative slope, and the motor potential. Since in a former study the BP was reduced in acute prefrontal traumatic brain injury (TBI) patients, the present study examined the MRPs' course in follow-up examinations. METHODS: Right index finger MRPs of 22 patients with contusions of the prefrontal cortex were recorded 12, 26, and 52 weeks after TBI and compared to controls. RESULTS: Within the patient group, a significant increase of the BP in the temporal course after TBI was observed. MRPs 12 and 26 weeks after TBI did not differ significantly from the control group. One year after TBI, significantly enhanced BPs were found. CONCLUSIONS: In the temporal course after prefrontal TBI, a recovery of the initially reduced BP was observed. The enhanced BP areas 1 year after TBI might represent the need for increased cognitive resources during movement preparation, supporting a recovered, but less effective neuronal network. SIGNIFICANCE: The present study represents the first longitudinal follow-up study of MRPs after prefrontal brain lesion. The observed changes reflect the plastic capacity of the brain, reorganizing the neuronal network function.

Impaired movement-related potentials in acute frontal traumatic brain injury.

OBJECTIVE: Focal brain lesions due to traumatic brain injury (TBI) do not only lead to functional deficits in the lesion area, but also disturb the structurally intact neuronal network connected to the lesion site. Therefore we hypothesized dysfunctions of the cortical motor network after frontal TBI. The movement related potential (MRP) is an EEG component related to voluntary movement consisting of the Bereitschaftspotential (BP), the negative slope (NS), and the motor potential (MP). The aim of our study was to demonstrate alterations in the movement related cortical network in the acute stage after TBI by comparing our patients' MRPs to those of a healthy control group. METHODS: EEGs of 22 patients with magnetic resonance imaging defined contusions of the prefrontal cortex were recorded within 8 weeks after TBI. We further recruited a healthy control group. The paradigm consisted of self-paced abductions of the right index finger. RESULTS: Compared to healthy controls, the BP in the patient group was significantly reduced and its onset delayed. Moreover, an enhanced contribution of the postrolandic hemisphere ipsilateral to the movement and a reduced contribution of the left frontal cortex, ipsilateral to the lesion in the majority of the patients, were observed during motor execution (MP). CONCLUSIONS: Anatomical connections between the prefrontal cortex and the supplementary motor area (SMA) are known to exist. We suggest that prefrontal lesions lead to reduced neuronal input into the SMA. This deficit in the preparatory motor network may cause the reduced BPs in our patients. Moreover, an increased need for attentional resources might explain the enhanced motor potentials during movement execution. In conclusion, we demonstrated altered MRPs in the acute stage after frontal TBI, which are a consequence of disturbed neuronal networks involved in the preparation and execution of voluntary movements.

Movement preparation in self-initiated versus externally triggered movements: an event-related fMRI-study.

In the present study, we used fMRI to investigate whether event-related preparatory processes of self-initiated and externally triggered movements differ. Twenty subjects were examined with 1000 T2*-weighted images in two consecutive sessions. During the first session subjects performed self-initiated abductions of the right index finger. For the second session subjects were instructed to perform the movements in response to visual cues. Number and timing of movements were matched between conditions. For statistical inference on multisubject level, random effects analyses were performed. Significantly enhanced activity during self-initiated compared to externally triggered movements was found within the left SMA, the left pre- and sensorimotor cortex, the right putamen, the left anterior cingulate gyrus, and the left inferior parietal lobe. The significantly increased activity during self-initiated in comparison to externally triggered movements might represent differential demands of the two conditions on the neuronal motor net during movement preparation, reflecting utilization of precise knowledge when to move in self-initiated movements. Our results emphasize a possible role of the primary motor cortex for movement preparation as observed in electrophysiological studies, but do not support a specific involvement of the dorsolateral prefrontal cortex as suggested by former block design studies.

Sparse imaging and continuous event-related fMRI in the visual domain: a systematic comparison.

Continuous image acquisition as used in most functional magnetic resonance imaging (fMRI) designs may conflict with specific experimental settings due to attendant, noisy gradient switching. In sparse fMRI, single images are recorded with a delay that allows the registration of the predicted peak of an evoked hemodynamic response (HDR). The aim of this study was to assess validity and sensitivity of single-trial sparse imaging within the visual domain. Thirteen subjects were scanned twice. Either continuous or sparse image acquisition was applied while participants viewed single trains of flashlights. Sparse fMRI results were compared to continuous event-related fMRI results on single- and multisubject level regarding spatial extent, overlap, and intensity of activation. In continuously recorded data, the variability of the HDR peak latency was examined because this measure determined the timing of sparse image acquisition. In sparse fMRI, the sensitivity was analyzed considering different numbers of averaged trials. Sparse imaging detected the core activity revealed using continuous fMRI. The intensity of signal changes detected by continuous or sparse fMRI was comparable. The HDR peak latency was stable across sessions, but intersubject and regional variability might have affected the power of sparse fMRI. In sparse imaging, adding trials resulted in extension of activation and improvement in statistical power. The comparison with established continuous fMRI confirms the validity of sparse imaging. Conventional event-related data acquisition and analysis provided more comprehensive results. However, only sparse fMRI offers the opportunity to apply stimuli and record further biosignals free of scanner-related artifacts during intervals without image acquisition.

[Quantification of acute muscle pain after whiplash injury using computer-aided pressure algesimetry]. / Quantifizierung akuter Nackenschmerzen nach Halswirbelsäulen-Beschleunigungsverletzung mittels computergestützter Druckalgesimetrie.

OBJECTIVE AND METHOD: The present study utilised the PC-interactive pressure algesimetry to quantify cervical pain after whiplash injury. Pressure painfulness of the splenius and trapezius muscles was investigated in patients with an acute cervical syndrome after whiplash injury and compared to that of healthy subjects. RESULTS: Pressure painfulness of neck and shoulder muscles was significantly increased in whiplash patients. The trapezius muscles were more painful left than right, probably due to the seat belt position. CONCLUSIONS: The computer-interactive pressure algesimetry enables a standardised, rater-independent quantification of cervical pain due to whiplash injury.

[Reduced contralateral preponderance of the movement-related potential during execution of self-initiated movements in acute prefrontal traumatic brain injury]. / Reduktion kontralateraler Präponderanz bewegungsbezogener Potenziale bei selbstinitiierten Fingerbewegungen nach präfrontaler Kontusion.

OBJECTIVES: An enhanced ipsilateral motor potential after prefrontal TBI is known. Our aim was to examine, whether this contributes to movement initiation or execution. METHODS: EEGs of 22 patients and 28 healthy controls were recorded. Subjects performed self-initiated movements of their right index finger. From the resulting movement-related potentials difference curves of corresponding left and right hemispheric electrodes were calculated. RESULTS: We observed significantly reduced difference curves at parietal electrodes P3 - P4 in the patient group during movement execution, but not at movement initiation. CONCLUSIONS: Our results point to compensatorily enhanced monitoring processes during movement execution following TBI. This is provided by enhanced activity of the ipsilateral postrolandic cortex, leading to the reduced preponderance observed in the present study.