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Background and Objective: Transcranial random noise stimulation (tRNS) is an emerging non-invasive brain stimulation technique to modulate brain function, with previous studies highlighting its considerable benefits in therapeutic stimulation of the motor system. However, high variability of results and bidirectional task-dependent effects limit more widespread clinical application. Task dependency largely results from a lack of understanding of the interaction between externally applied tRNS and the endogenous state of neural activity during stimulation. Hence, the aim of this study was to investigate the task dependency of tRNS-induced neuromodulation in the motor system using a finger-tapping task (FT) versus a go/no-go task (GNG). We hypothesized that the tasks would modulate tRNS’ effects on corticospinal excitability (CSE) and task performance in opposite directions.
Methods: Thirty healthy subjects received 10 min of tRNS of the dominant primary motor cortex in a double-blind, sham-controlled study design. tRNS was applied during two well-established tasks tied to diverging brain states. Accordingly, participants were randomly assigned to two equally-sized groups: the first group performed a simple motor training task (FT task), known primarily to increase CSE, while the second group performed an inhibitory control task (go/no-go task) associated with inhibition of CSE. To establish task-dependent effects of tRNS, CSE was evaluated prior to- and after stimulation with navigated transcranial magnetic stimulation.
Results: In an ‘activating’ motor task, tRNS during FT significantly facilitated CSE. FT task performance improvements, shown by training-related reductions in intertap intervals and increased number of finger taps, were similar for both tRNS and sham stimulation. In an ‘inhibitory’ motor task, tRNS during GNG left CSE unchanged while inhibitory control was enhanced as shown by slowed reaction times and enhanced task accuracy during and after stimulation.
Conclusion: We provide evidence that tRNS-induced neuromodulatory effects are task-dependent and that resulting enhancements are specific to the underlying task-dependent brain state. While mechanisms underlying this effect require further investigation, these findings highlight the potential of tRNS in enhancing task-dependent brain states to modulate human behavior.
Objectives: Navigated transcranial magnetic stimulation (nTMS) provides significant benefits over classic TMS. Yet, the acquisition of individual structural magnetic resonance images (MRIindividual) is a time-consuming, expensive, and not feasible prerequisite in all subjects for spatial tracking and anatomical guidance in nTMS studies. We hypothesize that spatial transformation can be used to adjust MRI templates to individual head shapes (MRIwarped) and that TMS parameters do not differ between nTMS using MRIindividual or MRIwarped.
Materials and Methods: Twenty identical TMS sessions, each including four different navigation conditions, were conducted in 10 healthy subjects (one female, 27.4 ± 3.8 years), i.e., twice per subject by two researchers to additionally assess interrater reliabilities. MRIindividual were acquired for all subjects. MRIwarped were obtained through the spatial transformation of a template MRI following a 5-, 9-and 36-point head surface registration (MRIwarped_5, MRIwarped_9, MRIwarped_36). Stimulation hotspot locations, resting motor threshold (RMT), 500 μV motor threshold (500 μV-MT), and mean absolute motor evoked potential difference (MAD) of primary motor cortex (M1) examinations were compared between nTMS using either MRIwarped variants or MRIindividual and non-navigated TMS.
Results: M1 hotspots were spatially consistent between MRIindividual and MRIwarped_36 (insignificant deviation by 4.79 ± 2.62 mm). MEP thresholds and variance were also equivalent between MRIindividual and MRIwarped_36 with mean differences of RMT by −0.05 ± 2.28% maximum stimulator output (%MSO; t(19) = −0.09, p = 0.923), 500 μV-MT by −0.15 ± 1.63%MSO (t(19) = −0.41, p = 0.686) and MAD by 70.5 ± 214.38 μV (t(19) = 1.47, p = 0.158). Intraclass correlations (ICC) of motor thresholds were between 0.88 and 0.97.
Conclusions: NTMS examinations of M1 yield equivalent topographical and functional results using MRIindividual and MRIwarped if a sufficient number of registration points are used.
Abstract
Background and purpose:Diagnosing a patient with headache as a migraineur is critical for state-of-the-art migrainemanagement. Screening tools are imperative means to improve the diagnostic yield in the primary care settings andspecialized clinics. This study aims to translate and assess the diagnostic accuracy of a German version of theID Migraine™as a widely used and efficient screening instrument.
Methods:
The Functional Assessment of Chronic Illness Therapy translation methodology was used to translate theoriginal three-itemID Migraine™, including a fourth question for aura, from the English language into the German language.Diagnostic accuracy of the GermanID Migraine™and predictors of false screening results were assessed among patientspresenting to a headache outpatient clinic of a tertiary care center in Germany over a 6-month period.
Results:
The translation procedure yielded a harmonized GermanID Migraine™and its diagnostic accuracy was assessedin 105 patients (80 female, 46.5+17.2 years of age), including 79 patients (75.2%) with migraine. The three-item GermanID Migraine™provides a sensitivity of 99%, specificity of 68%, and positive and negative predictive values of 90% and 95%,respectively, using a cutoff of2. Positive and negative predictive values in a general headache population are estimated tobe 74% and 98%, respectively. The aura question identified 18 out of 20 migraineurs with aura.
Conclusions:
The GermanID Migraine™is an accurate screening tool for migraine even in a challenging population of aspecialized outpatient clinic. Its diagnostic accuracy indicates a potential utility for screening in primary health care.
BACKGROUND Acute disseminated encephalomyelitis (ADEM) is a rare, acquired demyelination syndrome that causes cognitive impairment and
focal neurological deficits and may be fatal. The potentially reversible disease mainly affects children, often after vaccination or viral infection, but may
be seen rarely in adults.
OBSERVATIONS A 50-year-old woman presented with loss of visual acuity of the left eye. Magnetic resonance imaging (MRI) revealed an intra- and
suprasellar mass, which was removed successfully. On postoperative day 1, MRI showed gross total resection of the lesion and no surgery-related
complications. On postoperative day 2, the patient presented with a progressive left-sided hemiparesis, hemineglect, and decline of cognitive
performance. MRI showed white matter edema in both hemispheres. Cerebrospinal fluid analysis revealed mixed pleocytosis (355/mL) without further
evidence of infection. In synopsis of the findings, ADEM was diagnosed and treated with intravenous immunoglobulins. Shortly thereafter, the patient
recovered, and no sensorimotor deficits were detected in the follow-up examination.
LESSONS Pituitary gland pathologies are commonly treated by transsphenoidal surgery, with only minor risks for complications. A case of ADEM after
craniopharyngioma resection has not been published before and should be considered in case of progressive neurological deterioration with multiple
white matter lesions.
Objectives: The significance of pre-motor (PMC) corticospinal projections in a frontoparietal motor network remains elusive. Temporal activation patterns can provide valuable information about a region's engagement in a hierarchical network. Navigated transcranial magnetic stimulation (nTMS)-induced virtual lesions provide an excellent method to study cortical physiology by disrupting ongoing activity at high temporal resolution and anatomical precision. We use nTMS-induced virtual lesions applied during an established behavioral task demanding pre-motor activation to clarify the temporal activation pattern of pre-motor corticospinal projections.
Materials and Methods: Ten healthy volunteers participated in the experiment (4 female, mean age 24 ± 2 years, 1 left-handed). NTMS was used to map Brodmann areae 4 and 6 for primary motor (M1) and PMC corticospinal projections. We then determined the stimulator output intensity required to elicit a 1 mV motor evoked potential (1 mV-MT) through M1 nTMS. TMS pulse were randomly delivered at distinct time intervals (40, 60, 80, 100, 120, and 140 ms) at 1 mV-MT intensity to M1, PMC and the DLPFC (dorsolateral pre-frontal cortex; control condition) before participants had to perform major changes of their trajectory of movement during a tracing task. Each participant performed six trials (20 runs per trial). Task performance and contribution of regions under investigation was quantified through calculating the tracing error induced by the stimulation.
Results: A pre-motor stimulation hotspot could be identified in all participants (16.3 ± 1.7 mm medial, 18.6 ± 1.4 mm anterior to the M1 hotspot). NTMS over studied regions significantly affected task performance at discrete time intervals (F(10, 80) = 3.25, p = 0.001). NTMS applied over PMC 120 and 140 ms before changes in movement trajectory impaired task performance significantly more than when applied over M1 (p = 0.021 and p = 0.003) or DLPFC (p = 0.017 and p < 0.001). Stimulation intensity did not account for error size (β = −0.0074, p = 1).
Conclusions: We provide novel evidence that the role of pre-motor corticospinal projections extends beyond that of simple corticospinal motor output. Their activation is crucial for task performance early in the stage of motor preparation suggesting a significant role in shaping voluntary movement. Temporal patterns of human pre-motor activation are similar to that observed in intracortical electrophysiological studies in primates.
Stroke is the leading neurological cause of
adult long-term disability in Europe. Even though functional
consequences directly related to neurological impairment
are well studied, post-stroke trajectories of functional
health according to the International Classification of
Functioning, Disability and Health are poorly understood.
Particularly, no study investigated the relationship between
post-stroke trajectories of activities of daily living (ADL)
and self-rated health (SRH). However, such knowledge
is of major importance to identify patients at risk of
unfavourable courses. This prospective observational
study aims to investigate trajectories of ADL and SRH, and
their modifying factors in the course of the first year after
stroke.
Methods and analysis The study will consecutively enrol
300 patients admitted to a tertiary care hospital with acute
ischaemic stroke or transient ischaemic attack (TIA; Age,
Blood Pressure, Clinical Features, Duration of symptoms,
Diabetes score ≥3). Patient inclusion is planned from May
2021 to September 2022. All participants will complete
an interview assessing ADL, SRH, mental health, views
on ageing and resilience-related concepts. Participants
will be interviewed face-to-face 1–5 days post-stroke/
TIA in the hospital; and will be followed up after 6 weeks,
3 months, 6 months and 12 months via telephone. The
12-month follow-up will also include a neurological
assessment. Primary endpoints are ADL operationalised
by modified Rankin Scale scores and SRH. Secondary
outcomes are further measures of ADL, functional health,
physical activity, falls and fatigue. Views on ageing, social
support, resilience-related concepts, affect, frailty, illness
perceptions and loneliness will be examined as modifying
factors. Analyses will investigate the bidirectional
relationship between SRH and ADL using bivariate latent
change score models.
Ethics and dissemination The study has been approved
by the institutional review board of the University
Medicine Greifswald (Ref. BB 237/20). The results
will be disseminated through scientific publications,
conferences and media. Moreover, study results and
potential implications will be discussed with patient
representatives.
IntroductionA substantial number of patients diagnosed with COVID-19 experience long-term persistent symptoms. First evidence suggests that long-term symptoms develop largely independently of disease severity and include, among others, cognitive impairment. For these symptoms, there are currently no validated therapeutic approaches available. Cognitive training interventions are a promising approach to counteract cognitive impairment. Combining training with concurrent transcranial direct current stimulation (tDCS) may further increase and sustain behavioural training effects. Here, we aim to examine the effects of cognitive training alone or in combination with tDCS on cognitive performance, quality of life and mental health in patients with post-COVID-19 subjective or objective cognitive impairments.Methods and analysisThis study protocol describes a prospective randomised open endpoint-blinded trial. Patients with post-COVID-19 cognitive impairment will either participate in a 3-week cognitive training or in a defined muscle relaxation training (open-label interventions). Irrespective of their primary intervention, half of the cognitive training group will additionally receive anodal tDCS, all other patients will receive sham tDCS (double-blinded, secondary intervention). The primary outcome will be improvement of working memory performance, operationalised by an n-back task, at the postintervention assessment. Secondary outcomes will include performance on trained and untrained tasks and measures of health-related quality of life at postassessment and follow-up assessments (1 month after the end of the trainings).Ethics and disseminationEthical approval was granted by the Ethics Committee of the University Medicine Greifswald (number: BB 066/21). Results will be available through publications in peer-reviewed journals and presentations at national and international conferences.Trial registration numberNCT04944147.