@article{BrumbergKuestersAlMomanietal.2017, author = {Brumberg, Joachim and K{\"u}sters, Sebastian and Al-Momani, Ehab and Marotta, Giorgio and Cosgrove, Kelly P. and van Dyck, Christopher H. and Herrmann, Ken and Homola, Gy{\"o}rgy A. and Pezzoli, Gianni and Buck, Andreas K. and Volkmann, Jens and Samnick, Samuel and Isaias, Ioannis U.}, title = {Cholinergic activity and levodopa-induced dyskinesia: a multitracer molecular imaging study}, series = {Annals of Clinical and Translational Neurology}, volume = {4}, journal = {Annals of Clinical and Translational Neurology}, number = {9}, doi = {10.1002/acn3.438}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170406}, pages = {632-639}, year = {2017}, abstract = {Objective: To investigate the association between levodopa-induced dyskinesias and striatal cholinergic activity in patients with Parkinson's disease. Methods: This study included 13 Parkinson's disease patients with peak-of-dose levodopa-induced dyskinesias, 12 nondyskinetic patients, and 12 healthy controls. Participants underwent 5-[\(^{123}\)I]iodo-3-[2(S)-2-azetidinylmethoxy]pyridine single-photon emission computed tomography, a marker of nicotinic acetylcholine receptors, [\(^{123}\)I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane single-photon emission computed tomography, to measure dopamine reuptake transporter density and 2-[\(^{18}\)F]fluoro-2-deoxyglucose positron emission tomography to assess regional cerebral metabolic activity. Striatal binding potentials, uptake values at basal ganglia structures, and correlations with clinical variables were analyzed. Results: Density of nicotinic acetylcholine receptors in the caudate nucleus of dyskinetic subjects was similar to that of healthy controls and significantly higher to that of nondyskinetic patients, in particular, contralaterally to the clinically most affected side. Interpretation: Our findings support the hypothesis that the expression of dyskinesia may be related to cholinergic neuronal excitability in a dopaminergic-depleted striatum. Cholinergic signaling would play a role in maintaining striatal dopaminergic responsiveness, possibly defining disease phenotype and progression.}, language = {en} } @article{ContarinoSmitvandenDooletal.2016, author = {Contarino, Maria Fiorella and Smit, Marenka and van den Dool, Joost and Volkmann, Jens and Tijssen, Marina A. J.}, title = {Unmet Needs in the Management of Cervical Dystonia}, series = {Frontiers in Neurology}, volume = {7}, journal = {Frontiers in Neurology}, number = {165}, doi = {10.3389/fneur.2016.00165}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165225}, year = {2016}, abstract = {Cervical dystonia (CD) is a movement disorder which affects daily living of many patients. In clinical practice, several unmet treatment needs remain open. This article focuses on the four main aspects of treatment. We describe existing and emerging treatment approaches for CD, including botulinum toxin injections, surgical therapy, management of non-motor symptoms, and rehabilitation strategies. The unsolved issues regarding each of these treatments are identified and discussed, and possible future approaches and research lines are proposed.}, language = {en} } @article{CoenenAmtageVolkmannetal.2015, author = {Coenen, Volker A. and Amtage, Florian and Volkmann, Jens and Schl{\"a}pfer, Thomas E.}, title = {Deep Brain Stimulation in Neurological and Psychiatric Disorders}, series = {Deutsches {\"A}rzteblatt International}, volume = {112}, journal = {Deutsches {\"A}rzteblatt International}, doi = {10.3238/arztebl.2015.0519}, pages = {519 -- 526}, year = {2015}, abstract = {Background: Deep brain stimulation (DBS) is the chronic electrical stimulation of selected target sites in the brain through stereotactically implanted electrodes. More than 150 000 patients around the world have been treated to date with DBS for medically intractable conditions. The indications for DBS include movement disorders, epilepsy, and some types of mental illness. Methods: This review is based on relevant publications retrieved by a selective search in PubMed and the Cochrane Library, and on the current guidelines of the German Neurological Society (Deutsche Gesellschaft fur Neurologie, DGN). Results: DBS is usually performed to treat neurological diseases, most often movement disorders and, in particular, Parkinson's disease. Multiple randomized controlled trials (RCTs) have shown that DBS improves tremor, dyskinesia, and quality of life in patients with Parkinson's disease by 25\% to 50\%, depending on the rating scales used. DBS for tremor usually involves stimulation in the cerebello-thalamo-cortical regulatory loop. In an RCT of DBS for the treatment of primary generalized dystonia, the patients who underwent DBS experienced a 39.3\% improvement of dystonia, compared to only 4.9\% in the control group. Two multicenter trials of DBS for depression were terminated early because of a lack of efficacy. Conclusion: DBS is an established treatment for various neurological and psychiatric diseases. It has been incorporated in the DGN guidelines and is now considered a standard treatment for advanced Parkinson's disease. The safety and efficacy of DBS can be expected to improve with the application of new technical developments in electrode geometry and new imaging techniques. Controlled trials would be helpful so that DBS could be extended to further indications, particularly psychiatric ones.}, language = {en} } @article{IpIsaiasKuscheTekinetal.2016, author = {Ip, Chi Wang and Isaias, Ioannis U. and Kusche-Tekin, Burak B. and Klein, Dennis and Groh, Janos and O´Leary, Aet and Knorr, Susanne and Higuchi, Takahiro and Koprich, James B. and Brotchie, Jonathan M. and Toyka, Klaus V. and Reif, Andreas and Volkmann, Jens}, title = {Tor1a+/- mice develop dystonia-like movements via a striatal dopaminergic dysregulation triggered by peripheral nerve injury}, series = {Acta Neuropathologica Communications}, volume = {4}, journal = {Acta Neuropathologica Communications}, number = {108}, doi = {10.1186/s40478-016-0375-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147839}, year = {2016}, abstract = {Isolated generalized dystonia is a central motor network disorder characterized by twisted movements or postures. The most frequent genetic cause is a GAG deletion in the Tor1a (DYT1) gene encoding torsinA with a reduced penetrance of 30-40 \% suggesting additional genetic or environmental modifiers. Development of dystonia-like movements after a standardized peripheral nerve crush lesion in wild type (wt) and Tor1a+/- mice, that express 50 \% torsinA only, was assessed by scoring of hindlimb movements during tail suspension, by rotarod testing and by computer-assisted gait analysis. Western blot analysis was performed for dopamine transporter (DAT), D1 and D2 receptors from striatal and quantitative RT-PCR analysis for DAT from midbrain dissections. Autoradiography was used to assess the functional DAT binding in striatum. Striatal dopamine and its metabolites were analyzed by high performance liquid chromatography. After nerve crush injury, we found abnormal posturing in the lesioned hindlimb of both mutant and wt mice indicating the profound influence of the nerve lesion (15x vs. 12x relative to control) resembling human peripheral pseudodystonia. In mutant mice the phenotypic abnormalities were increased by about 40 \% (p < 0.05). This was accompanied by complex alterations of striatal dopamine homeostasis. Pharmacological blockade of dopamine synthesis reduced severity of dystonia-like movements, whereas treatment with L-Dopa aggravated these but only in mutant mice suggesting a DYT1 related central component relevant to the development of abnormal involuntary movements. Our findings suggest that upon peripheral nerve injury reduced torsinA concentration and environmental stressors may act in concert in causing the central motor network dysfunction of DYT1 dystonia.}, language = {en} } @article{MencacciIsaiasReichetal.2014, author = {Mencacci, Niccol{\´o} E. and Isaias, Ioannis U. and Reich, Martin M. and Ganos, Christos and Plagnol, Vincent and Polke, James M. and Bras, Jose and Hersheson, Joshua and Stamelou, Maria and Pittman, Alan M. and Noyce, Alastair J. and Mok, Kin Y. and Opladen, Thomas and Kunstmann, Erdmute and Hodecker, Sybille and M{\"u}nchau, Alexander and Volkmann, Jens and Samnick, Samuel and Sidle, Katie and Nanji, Tina and Sweeney, Mary G. and Houlden, Henry and Batla, Amit and Zecchinelli, Anna L. and Pezzoli, Gianni and Marotta, Giorgio and Lees, Andrew and Alegria, Paulo and Krack, Paul and Cormier-Dequaire, Florence and Lesage, Suzanne and Brice, Alexis and Heutink, Peter and Gasser, Thomas and Lubbe, Steven J. and Morris, Huw R. and Taba, Pille and Koks, Sulev and Majounie, Elisa and Gibbs, J. Raphael and Singleton, Andrew and Hardy, John and Klebe, Stephan and Bhatia, Kailash P. and Wood, Nicholas W.}, title = {Parkinson's disease in GTP cyclohydrolase 1 mutation carriers}, series = {Brain}, volume = {137}, journal = {Brain}, number = {9}, doi = {10.1093/brain/awu179}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121268}, pages = {2480-92}, year = {2014}, abstract = {GTP cyclohydrolase 1, encoded by the GCH1 gene, is an essential enzyme for dopamine production in nigrostriatal cells. Loss-of-function mutations in GCH1 result in severe reduction of dopamine synthesis in nigrostriatal cells and are the most common cause of DOPA-responsive dystonia, a rare disease that classically presents in childhood with generalized dystonia and a dramatic long-lasting response to levodopa. We describe clinical, genetic and nigrostriatal dopaminergic imaging ([(123)I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) tropane single photon computed tomography) findings of four unrelated pedigrees with DOPA-responsive dystonia in which pathogenic GCH1 variants were identified in family members with adult-onset parkinsonism. Dopamine transporter imaging was abnormal in all parkinsonian patients, indicating Parkinson's disease-like nigrostriatal dopaminergic denervation. We subsequently explored the possibility that pathogenic GCH1 variants could contribute to the risk of developing Parkinson's disease, even in the absence of a family history for DOPA-responsive dystonia. The frequency of GCH1 variants was evaluated in whole-exome sequencing data of 1318 cases with Parkinson's disease and 5935 control subjects. Combining cases and controls, we identified a total of 11 different heterozygous GCH1 variants, all at low frequency. This list includes four pathogenic variants previously associated with DOPA-responsive dystonia (Q110X, V204I, K224R and M230I) and seven of undetermined clinical relevance (Q110E, T112A, A120S, D134G, I154V, R198Q and G217V). The frequency of GCH1 variants was significantly higher (Fisher's exact test P-value 0.0001) in cases (10/1318 = 0.75\%) than in controls (6/5935 = 0.1\%; odds ratio 7.5; 95\% confidence interval 2.4-25.3). Our results show that rare GCH1 variants are associated with an increased risk for Parkinson's disease. These findings expand the clinical and biological relevance of GTP cycloydrolase 1 deficiency, suggesting that it not only leads to biochemical striatal dopamine depletion and DOPA-responsive dystonia, but also predisposes to nigrostriatal cell loss. Further insight into GCH1-associated pathogenetic mechanisms will shed light on the role of dopamine metabolism in nigral degeneration and Parkinson's disease.}, language = {en} } @article{IsaiasSpiegelBrumbergetal.2014, author = {Isaias, Ioannis Ugo and Spiegel, J{\"o}rg and Brumberg, Joachim and Cosgrove, Kelly P. and Marotta, Giorgio and Oishi, Naoya and Higuchi, Takahiro and K{\"u}sters, Sebastian and Schiller, Markus and Dillmann, Ulrich and van Dyck, Christopher H. and Buck, Andreas and Herrmann, Ken and Schloegl, Susanne and Volkmann, Jens and Lassmann, Michael and Fassbender, Klaus and Lorenz, Reinhard and Samnick, Samuel}, title = {Nicotinic acetylcholine receptor density in cognitively intact subjects at an early stage of Parkinson's disease}, series = {Frontiers in Aging Neuroscience}, volume = {6}, journal = {Frontiers in Aging Neuroscience}, doi = {10.3389/fnagi.2014.00213}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119351}, pages = {213}, year = {2014}, abstract = {We investigated in vivo brain nicotinic acetylcholine receptor (nAChR) distribution in cognitively intact subjects with Parkinson's disease (PD) at an early stage of the disease. Fourteen patients and 13 healthy subjects were imaged with single photon emission computed tomography and the radiotracer 5-[(123)I]iodo-3-[2(S)-2-azetidinylmethoxy]pyridine ([(123)I]5IA). Patients were selected according to several criteria, including short duration of motor signs (<7 years) and normal scores at an extensive neuropsychological evaluation. In PD patients, nAChR density was significantly higher in the putamen, the insular cortex and the supplementary motor area and lower in the caudate nucleus, the orbitofrontal cortex, and the middle temporal gyrus. Disease duration positively correlated with nAChR density in the putamen ipsilateral (ρ = 0.56, p < 0.05) but not contralateral (ρ = 0.49, p = 0.07) to the clinically most affected hemibody. We observed, for the first time in vivo, higher nAChR density in brain regions of the motor and limbic basal ganglia circuits of subjects with PD. Our findings support the notion of an up-regulated cholinergic activity at the striatal and possibly cortical level in cognitively intact PD patients at an early stage of disease.}, language = {en} } @article{IsaiasDipaolaMichietal.2014, author = {Isaias, Ioannis Ugo and Dipaola, Mariangela and Michi, Marlies and Marzegan, Alberto and Volkmann, Jens and Rodocanachi Roidi, Mariana L. and Frigo, Carlo Albino and Cavallari, Paolo}, title = {Gait Initiation in Children with Rett Syndrome}, series = {PLoS ONE}, volume = {9}, journal = {PLoS ONE}, number = {4}, issn = {1932-6203}, doi = {10.1371/journal.pone.0092736}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119789}, pages = {e92736}, year = {2014}, abstract = {Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait.}, language = {en} } @article{VolkmannAlbaneseAntoninietal.2013, author = {Volkmann, Jens and Albanese, Alberto and Antonini, Angelo and Chaudhuri, K. Ray and Clarke, Karl E. and de Bie, Rob M. A. and Deuschl, G{\"u}nther and Eggert, Karla and Houeto, Jean-Luc and Kulisevsky, Jaime and Nyholm, Dag and Odin, Per and Ostergaard, Karen and Poewe, Werner and Pollak, Pierre and Rabey, Jose Martin and Rascol, Olivier and Ruzicka, Evzen and Samuel, Michael and Speelman, Hans and Sydow, Olof and Valldeoriola, Francesc and van der Linden, Chris and Oertel, Wolfgang}, title = {Selecting deep brain stimulation or infusion therapies in advanced Parkinson's disease: an evidence-based review}, series = {Journal of Neurology}, volume = {260}, journal = {Journal of Neurology}, doi = {10.1007/s00415-012-6798-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132373}, pages = {2701-2714}, year = {2013}, abstract = {Motor complications in Parkinson's disease (PD) result from the short half-life and irregular plasma fluctuations of oral levodopa. When strategies of providing more continuous dopaminergic stimulation by adjusting oral medication fail, patients may be candidates for one of three device-aided therapies: deep brain stimulation (DBS), continuous subcutaneous apomorphine infusion, or continuous duodenal/jejunal levodopa/carbidopa pump infusion (DLI). These therapies differ in their invasiveness, side-effect profile, and the need for nursing care. So far, very few comparative studies have evaluated the efficacy of the three device-aided therapies for specific motor problems in advanced PD. As a result, neurologists currently lack guidance as to which therapy could be most appropriate for a particular PD patient. A group of experts knowledgeable in all three therapies reviewed the currently available literature for each treatment and identified variables of clinical relevance for choosing one of the three options such as type of motor problems, age, and cognitive and psychiatric status. For each scenario, pragmatic and (if available) evidence-based recommendations are provided as to which patients could be candidates for either DBS, DLI, or subcutaneous apomorphine.}, language = {en} } @article{IsaiasMarzeganPezzolietal.2012, author = {Isaias, Ioannis U. and Marzegan, Alberto and Pezzoli, Gianni and Marotta, Giorgio and Canesi, Margherita and Biella, Gabriele E. M. and Volkmann, Jens and Cavallari, Paolo}, title = {A role for locus coeruleus in Parkinson tremor}, series = {Frontiers in Human Neuroscience}, volume = {5}, journal = {Frontiers in Human Neuroscience}, number = {179}, doi = {10.3389/fnhum.2011.00179}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133955}, year = {2012}, abstract = {We analyzed rest tremor, one of the etiologically most elusive hallmarks of Parkinson disease(PD), in 12 consecutive PD patients during a specific task activating the locus coeruleus (LC) to investigate a putative role of noradrenaline (NA) in tremor generation and suppression. Clinical diagnosis was confirmed in all subjects by reduced dopamine reuptake transporter (DAT) binding values investigated by single photon computed tomography imaging (SPECT) with [\(^{123}\)I] N-\(\omega\)-fluoropropyl-2 \(\beta\)-carbomethoxy-3 \(\beta\)-(4-iodophenyl) tropane (FP-CIT). The intensity of tremor (i.e., the power of Electromyography [EMG] signals), but not its frequency, significantly increased during the task. In six subjects, tremor appeared selectively during the task. In a second part of the study, we retrospectively reviewed SPECT with FP-CIT data and confirmed the lack of correlation between dopaminergic loss and tremor by comparing DAT binding values of 82 PD subjects with bilateral tremor (n = 27), unilateral tremor (n = 22), and no tremor (n = 33). This study suggests a role of the LC in Parkinson tremor.}, language = {en} } @article{IsaiasVolkmannMarzeganetal.2012, author = {Isaias, Ioannis U. and Volkmann, Jens and Marzegan, Alberto and Marotta, Giorgio and Cavallari, Paolo and Pezzoli, Gianni}, title = {The Influence of Dopaminergic Striatal Innervation on Upper Limb Locomotor Synergies}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {12}, doi = {10.1371/journal.pone.0051464}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133976}, pages = {e51464}, year = {2012}, abstract = {To determine the role of striatal dopaminergic innervation on upper limb synergies during walking, we measured arm kinematics in 13 subjects with Parkinson disease. Patients were recruited according to several inclusion criteria to represent the best possible in vivo model of dopaminergic denervation. Of relevance, we included only subjects with normal spatio-temporal parameters of the stride and gait speed to avoid an impairment of upper limbs locomotor synergies as a consequence of gait impairment per se. Dopaminergic innervation of the striatum was measured by FP-CIT and SPECT. All patients showed a reduction of gait-associated arms movement. No linear correlation was found between arm ROM reduction and contralateral dopaminergic putaminal innervation loss. Still, a partition analysis revealed a 80\% chance of reduced arm ROM when putaminal dopamine content loss was >47\%. A significant correlation was described between the asymmetry indices of the swinging of the two arms and dopaminergic striatal innervation. When arm ROM was reduced, we found a positive correlation between upper-lower limb phase shift modulation ( at different gait velocities) and striatal dopaminergic innervation. These findings are preliminary evidence that dopaminergic striatal tone plays a modulatory role in upper-limb locomotor synergies and upper-lower limb coupling while walking at different velocities.}, language = {en} } @article{NguemeniHiewKoegleretal.2021, author = {Nguemeni, Carine and Hiew, Shawn and K{\"o}gler, Stefanie and Homola, Gy{\"o}rgy A. and Volkmann, Jens and Zeller, Daniel}, title = {Split-belt training but not cerebellar anodal tDCS improves stability control and reduces risk of fall in patients with multiple sclerosis}, series = {Brain Sciences}, volume = {12}, journal = {Brain Sciences}, number = {1}, issn = {2076-3425}, doi = {10.3390/brainsci12010063}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252179}, year = {2021}, abstract = {The objective of this study was to examine the therapeutic potential of multiple sessions of training on a split-belt treadmill (SBT) combined with cerebellar anodal transcranial direct current stimulation (tDCS) on gait and balance in People with Multiple Sclerosis (PwMS). Twenty-two PwMS received six sessions of anodal (PwMS\(_{real}\), n = 12) or sham (PwMS\(_{sham}\), n = 10) tDCS to the cerebellum prior to performing the locomotor adaptation task on the SBT. To evaluate the effect of the intervention, functional gait assessment (FGA) scores and distance walked in 2 min (2MWT) were measured at the baseline (T0), day 6 (T5), and at the 4-week follow up (T6). Locomotor performance and changes of motor outcomes were similar in PwMS\(_{real}\) and PwMS\(_{sham}\) independently from tDCS mode applied to the cerebellum (anodal vs. sham, on FGA, p = 0.23; and 2MWT, p = 0.49). When the data were pooled across the groups to investigate the effects of multiple sessions of SBT training alone, significant improvement of gait and balance was found on T5 and T6, respectively, relative to baseline (FGA, p < 0.001 for both time points). The FGA change at T6 was significantly higher than at T5 (p = 0.01) underlining a long-lasting improvement. An improvement of the distance walked during the 2MWT was also observed on T5 and T6 relative to T0 (p = 0.002). Multiple sessions of SBT training resulted in a lasting improvement of gait stability and endurance, thus potentially reducing the risk of fall as measured by FGA and 2MWT. Application of cerebellar tDCS during SBT walking had no additional effect on locomotor outcomes.}, language = {en} } @article{BellingerAltenmuellerVolkmann2017, author = {Bellinger, Daniel and Altenm{\"u}ller, Eckart and Volkmann, Jens}, title = {Perception of time in music in patients with Parkinson's disease - The processing of musical syntax compensates for rhythmic deficits}, series = {Frontiers in Neuroscience}, volume = {11}, journal = {Frontiers in Neuroscience}, doi = {10.3389/fnins.2017.00068}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171805}, year = {2017}, abstract = {Objective: Perception of time as well as rhythm in musical structures rely on complex brain mechanisms and require an extended network of multiple neural sources. They are therefore sensitive to impairment. Several psychophysical studies have shown that patients with Parkinson's disease (PD) have deficits in perceiving time and rhythms due to a malfunction of the basal ganglia (BG) network. Method: In this study we investigated the time perception of PD patients during music perception by assessing their just noticeable difference (JND) in the time perception of a complex musical Gestalt. We applied a temporal discrimination task using a short melody with a clear beat-based rhythm. Among the subjects, 26 patients under L-Dopa administration and 21 age-matched controls had to detect an artificially delayed time interval in the range between 80 and 300 ms in the middle of the musical period. We analyzed the data by (a) calculating the detection threshold directly, (b) by extrapolating the JNDs, (c) relating it to musical expertise. Results: Patients differed from controls in the detection of time-intervals between 220 and 300 ms (*p = 0.0200, n = 47). Furthermore, this deficit depended on the severity of the disease (*p = 0.0452; n = 47). Surprisingly, PD patients did not show any deficit of their JND compared to healthy controls, although the results showed a trend (*p = 0.0565, n = 40). Furthermore, no significant difference of the JND was found according to the severity of the disease. Additionally, musically trained persons seemed to have lower thresholds in detecting deviations in time and syntactic structures of music (*p = 0.0343, n = 39). Conclusion: As an explanation of these results, we would like to propose the hypothesis of a time-syntax-congruency in music perception suggesting that processing of time and rhythm is a Gestalt process and that cortical areas involved in processing of musical syntax may compensate for impaired BG circuits that are responsible for time processing and rhythm perception. This mechanism may emerge more strongly as the deficits in time processing and rhythm perception progress. Furthermore, we presume that top-down-bottom-up-processes interfere additionally and interact in this context of compensation.}, language = {en} } @article{FriedrichEldebakeyRoothansetal.2022, author = {Friedrich, Maximilian U. and Eldebakey, Hazem and Roothans, Jonas and Capetian, Philipp and Zwergal, Andreas and Volkmann, Jens and Reich, Martin}, title = {Current-dependent ocular tilt reaction in deep brain stimulation of the subthalamic nucleus: Evidence for an incerto-interstitial pathway?}, series = {European Journal of Neurology}, volume = {29}, journal = {European Journal of Neurology}, number = {5}, doi = {10.1111/ene.15257}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318700}, pages = {1545 -- 1549}, year = {2022}, abstract = {Background and purpose The aim was to characterize a combined vestibular, ocular motor and postural syndrome induced by deep brain stimulation (DBS) of the subthalamic nucleus in a patient with Parkinson's disease. Methods In a systematic DBS programming session, eye, head and trunk position in roll and pitch plane were documented as a function of stimulation amplitude and field direction. Repeat ocular coherence tomography was used to estimate ocular torsion. The interstitial nucleus of Cajal (INC), zona incerta (ZI) and ascending vestibular fibre tracts were segmented on magnetic resonance imaging using both individual and normative structural connectomic data. Thresholded symptom-associated volumes of tissue activated (VTA) were calculated based on documented stimulation parameters. Results Ipsilateral ocular tilt reaction and body lateropulsion as well as contralateral torsional nystagmus were elicited by the right electrode in a current-dependent manner and subsided after DBS deactivation. With increasing currents, binocular tonic upgaze and body retropulsion were observed. Symptoms were consistent with an irritative effect on the INC. Symptom-associated VTA was found to overlap with the dorsal ZI and the ipsilateral vestibulothalamic tract, while lying rather distant to the INC proper. A ZI-to-INC 'incerto-interstitial' tract with contact to the medial-uppermost portion of the VTA could be traced. Conclusion Unilateral stimulation of INC-related circuitry induces an ipsilateral vestibular, ocular motor and postural roll-plane syndrome, which converts into a pitch-plane syndrome when functional activation expands bilaterally. In this case, tractography points to an incerto-interstitial pathway, a tract previously only characterized in non-human primates. Directional current steering proved useful in managing this rare side effect.}, language = {en} } @article{BadrMcFlederWuetal.2022, author = {Badr, Mohammad and McFleder, Rhonda L. and Wu, Jingjing and Knorr, Susanne and Koprich, James B. and H{\"u}nig, Thomas and Brotchie, Jonathan M. and Volkmann, Jens and Lutz, Manfred B. and Ip, Chi Wang}, title = {Expansion of regulatory T cells by CD28 superagonistic antibodies attenuates neurodegeneration in A53T-α-synuclein Parkinson's disease mice}, series = {Journal of Neuroinflammation}, volume = {19}, journal = {Journal of Neuroinflammation}, doi = {10.1186/s12974-022-02685-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300580}, year = {2022}, abstract = {Background Regulatory CD4\(^+\)CD25\(^+\)FoxP3\(^+\) T cells (Treg) are a subgroup of T lymphocytes involved in maintaining immune balance. Disturbance of Treg number and impaired suppressive function of Treg correlate with Parkinson's disease severity. Superagonistic anti-CD28 monoclonal antibodies (CD28SA) activate Treg and cause their expansion to create an anti-inflammatory environment. Methods Using the AAV1/2-A53T-α-synuclein Parkinson's disease mouse model that overexpresses the pathogenic human A53T-α-synuclein (hαSyn) variant in dopaminergic neurons of the substantia nigra, we assessed the neuroprotective and disease-modifying efficacy of a single intraperitoneal dose of CD28SA given at an early disease stage. Results CD28SA led to Treg expansion 3 days after delivery in hαSyn Parkinson's disease mice. At this timepoint, an early pro-inflammation was observed in vehicle-treated hαSyn Parkinson's disease mice with elevated percentages of CD8\(^+\)CD69\(^+\) T cells in brain and increased levels of interleukin-2 (IL-2) in the cervical lymph nodes and spleen. These immune responses were suppressed in CD28SA-treated hαSyn Parkinson's disease mice. Early treatment with CD28SA attenuated dopaminergic neurodegeneration in the SN of hαSyn Parkinson's disease mice accompanied with reduced brain numbers of activated CD4\(^+\), CD8\(^+\) T cells and CD11b\(^+\) microglia observed at the late disease-stage 10 weeks after AAV injection. In contrast, a later treatment 4 weeks after AAV delivery failed to reduce dopaminergic neurodegeneration. Conclusions Our data indicate that immune modulation by Treg expansion at a timepoint of overt inflammation is effective for treatment of hαSyn Parkinson's disease mice and suggest that the concept of early immune therapy could pose a disease-modifying option for Parkinson's disease patients.}, language = {en} } @article{SchuhmannStollPappetal.2019, author = {Schuhmann, Michael K. and Stoll, Guido and Papp, Lena and Bohr, Arne and Volkmann, Jens and Fluri, Felix}, title = {Electrical stimulation of the mesencephalic locomotor region has no impact on blood-brain barrier alterations after cerebral photothrombosis in rats}, series = {International Journal of Molecular Science}, volume = {20}, journal = {International Journal of Molecular Science}, number = {16}, issn = {1422-0067}, doi = {10.3390/ijms20164036}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201284}, year = {2019}, abstract = {Blood-brain barrier (BBB) disruption is a critical event after ischemic stroke, which results in edema formation and hemorrhagic transformation of infarcted tissue. BBB dysfunction following stroke is partly mediated by proinflammatory agents. We recently have shown that high frequency stimulation of the mesencephalic locomotor region (MLR-HFS) exerts an antiapoptotic and anti-inflammatory effect in the border zone of cerebral photothrombotic stroke in rats. Whether MLR-HFS also has an impact on BBB dysfunction in the early stage of stroke is unknown. In this study, rats were subjected to photothrombotic stroke of the sensorimotor cortex and implantation of a stimulating microelectrode into the ipsilesional MLR. Thereafter, either HFS or sham stimulation of the MLR was applied for 24 h. After scarifying the rats, BBB disruption was assessed by determining albumin extravasation and tight junction integrity (claudin 3, claudin 5, and occludin) using Western blot analyses and immunohistochemistry. In addition, by applying zymography, expression of pro-metalloproteinase-9 (pro-MMP-9) was analyzed. No differences were found regarding infarct size and BBB dysfunction between stimulated and unstimulated animals 24 h after induction of stroke. Our results indicate that MLR-HFS neither improves nor worsens the damaged BBB after stroke. Attenuating cytokines/chemokines in the perilesional area, as mediated by MLR-HFS, tend to play a less significant role in preventing the BBB integrity.}, language = {en} } @article{SchuhmannPappStolletal.2021, author = {Schuhmann, Michael K. and Papp, Lena and Stoll, Guido and Blum, Robert and Volkmann, Jens and Fluri, Felix}, title = {Mesencephalic electrical stimulation reduces neuroinflammation after photothrombotic stroke in rats by targeting the cholinergic anti-inflammatory pathway}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {3}, issn = {1422-0067}, doi = {10.3390/ijms22031254}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259099}, year = {2021}, abstract = {Inflammation is crucial in the pathophysiology of stroke and thus a promising therapeutic target. High-frequency stimulation (HFS) of the mesencephalic locomotor region (MLR) reduces perilesional inflammation after photothrombotic stroke (PTS). However, the underlying mechanism is not completely understood. Since distinct neural and immune cells respond to electrical stimulation by releasing acetylcholine, we hypothesize that HFS might trigger the cholinergic anti-inflammatory pathway via activation of the α7 nicotinic acetylcholine receptor (α7nAchR). To test this hypothesis, rats underwent PTS and implantation of a microelectrode into the MLR. Three hours after intervention, either HFS or sham-stimulation of the MLR was applied for 24 h. IFN-γ, TNF-α, and IL-1α were quantified by cytometric bead array. Choline acetyltransferase (ChAT)\(^+\) CD4\(^+\)-cells and α7nAchR\(^+\)-cells were quantified visually using immunohistochemistry. Phosphorylation of NFĸB, ERK1/2, Akt, and Stat3 was determined by Western blot analyses. IFN-γ, TNF-α, and IL-1α were decreased in the perilesional area of stimulated rats compared to controls. The number of ChAT\(^+\) CD4\(^+\)-cells increased after MLR-HFS, whereas the amount of α7nAchR\(^+\)-cells was similar in both groups. Phospho-ERK1/2 was reduced significantly in stimulated rats. The present study suggests that MLR-HFS may trigger anti-inflammatory processes within the perilesional area by modulating the cholinergic system, probably via activation of the α7nAchR.}, language = {en} } @article{SchuhmannStollBohretal.2019, author = {Schuhmann, Michael K. and Stoll, Guido and Bohr, Arne and Volkmann, Jens and Fluri, Felix}, title = {Electrical stimulation of the mesencephalic locomotor region attenuates neuronal loss and cytokine expression in the perifocal region of photothrombotic stroke in rats}, series = {International Journal of Molecular Science}, volume = {20}, journal = {International Journal of Molecular Science}, number = {9}, issn = {1422-0067}, doi = {10.3390/ijms20092341}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201355}, year = {2019}, abstract = {Deep brain stimulation of the mesencephalic locomotor region (MLR) improves the motor symptoms in Parkinson's disease and experimental stroke by intervening in the motor cerebral network. Whether high-frequency stimulation (HFS) of the MLR is involved in non-motor processes, such as neuroprotection and inflammation in the area surrounding the photothrombotic lesion, has not been elucidated. This study evaluates whether MLR-HFS exerts an anti-apoptotic and anti-inflammatory effect on the border zone of cerebral photothrombotic stroke. Rats underwent photothrombotic stroke of the right sensorimotor cortex and the implantation of a microelectrode into the ipsilesional MLR. After intervention, either HFS or sham stimulation of the MLR was applied for 24 h. The infarct volumes were calculated from consecutive brain sections. Neuronal apoptosis was analyzed by TUNEL staining. Flow cytometry and immunohistochemistry determined the perilesional inflammatory response. Neuronal apoptosis was significantly reduced in the ischemic penumbra after MLR-HFS, whereas the infarct volumes did not differ between the groups. MLR-HFS significantly reduced the release of cytokines and chemokines within the ischemic penumbra. MLR-HFS is neuroprotective and it reduces pro-inflammatory mediators in the area that surrounds the photothrombotic stroke without changing the number of immune cells, which indicates that MLR-HFS enables the function of inflammatory cells to be altered on a molecular level.}, language = {en} } @article{KuzkinaBargarSchmittetal.2021, author = {Kuzkina, Anastasia and Bargar, Connor and Schmitt, Daniela and R{\"o}ßle, Jonas and Wang, Wen and Schubert, Anna-Lena and Tatsuoka, Curtis and Gunzler, Steven A. and Zou, Wen-Quan and Volkmann, Jens and Sommer, Claudia and Doppler, Kathrin and Chen, Shu G.}, title = {Diagnostic value of skin RT-QuIC in Parkinson's disease: a two-laboratory study}, series = {NPJ Parkinson's Disease}, volume = {7}, journal = {NPJ Parkinson's Disease}, number = {1}, doi = {10.1038/s41531-021-00242-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260451}, year = {2021}, abstract = {Skin alpha-synuclein deposition is considered a potential biomarker for Parkinson's disease (PD). Real-time quaking-induced conversion (RT-QuIC) is a novel, ultrasensitive, and efficient seeding assay that enables the detection of minute amounts of alpha-synuclein aggregates. We aimed to determine the diagnostic accuracy, reliability, and reproducibility of alpha-synuclein RT-QuIC assay of skin biopsy for diagnosing PD and to explore its correlation with clinical markers of PD in a two-center inter-laboratory comparison study. Patients with clinically diagnosed PD (n = 34), as well as control subjects (n = 30), underwent skin punch biopsy at multiple sites (neck, lower back, thigh, and lower leg). The skin biopsy samples (198 in total) were divided in half to be analyzed by RT-QuIC assay in two independent laboratories. The a-synuclein RT-QuIC assay of multiple skin biopsies supported the clinical diagnosis of PD with a diagnostic accuracy of 88.9\% and showed a high degree of inter-rater agreement between the two laboratories (92.2\%). Higher alpha-synuclein seeding activity in RT-QuIC was shown in patients with longer disease duration and more advanced disease stage and correlated with the presence of REM sleep behavior disorder, cognitive impairment, and constipation. The alpha-synuclein RT-QuIC assay of minimally invasive skin punch biopsy is a reliable and reproducible biomarker for Parkinson's disease. Moreover, alpha-synuclein RT-QuIC seeding activity in the skin may serve as a potential indicator of progression as it correlates with the disease stage and certain non-motor symptoms.}, language = {en} } @article{FriedrichSchneiderBuerkleinetal.2023, author = {Friedrich, Maximilian U. and Schneider, Erich and Buerklein, Miriam and Taeger, Johannes and Hartig, Johannes and Volkmann, Jens and Peach, Robert and Zeller, Daniel}, title = {Smartphone video nystagmography using convolutional neural networks: ConVNG}, series = {Journal of Neurology}, volume = {270}, journal = {Journal of Neurology}, number = {5}, doi = {10.1007/s00415-022-11493-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324526}, pages = {2518-2530}, year = {2023}, abstract = {Background Eye movement abnormalities are commonplace in neurological disorders. However, unaided eye movement assessments lack granularity. Although videooculography (VOG) improves diagnostic accuracy, resource intensiveness precludes its broad use. To bridge this care gap, we here validate a framework for smartphone video-based nystagmography capitalizing on recent computer vision advances. Methods A convolutional neural network was fine-tuned for pupil tracking using > 550 annotated frames: ConVNG. In a cross-sectional approach, slow-phase velocity of optokinetic nystagmus was calculated in 10 subjects using ConVNG and VOG. Equivalence of accuracy and precision was assessed using the "two one-sample t-test" (TOST) and Bayesian interval-null approaches. ConVNG was systematically compared to OpenFace and MediaPipe as computer vision (CV) benchmarks for gaze estimation. Results ConVNG tracking accuracy reached 9-15\% of an average pupil diameter. In a fully independent clinical video dataset, ConVNG robustly detected pupil keypoints (median prediction confidence 0.85). SPV measurement accuracy was equivalent to VOG (TOST p < 0.017; Bayes factors (BF) > 24). ConVNG, but not MediaPipe, achieved equivalence to VOG in all SPV calculations. Median precision was 0.30°/s for ConVNG, 0.7°/s for MediaPipe and 0.12°/s for VOG. ConVNG precision was significantly higher than MediaPipe in vertical planes, but both algorithms' precision was inferior to VOG. Conclusions ConVNG enables offline smartphone video nystagmography with an accuracy comparable to VOG and significantly higher precision than MediaPipe, a benchmark computer vision application for gaze estimation. This serves as a blueprint for highly accessible tools with potential to accelerate progress toward precise and personalized Medicine.}, language = {en} } @article{RauschenbergerBehnkeGrotemeyeretal.2022, author = {Rauschenberger, Lisa and Behnke, Jennifer and Grotemeyer, Alexander and Knorr, Susanne and Volkmann, Jens and Ip, Chi Wang}, title = {Age-dependent neurodegeneration and neuroinflammation in a genetic A30P/A53T double-mutated α-synuclein mouse model of Parkinson's disease}, series = {Neurobiology of Disease}, volume = {171}, journal = {Neurobiology of Disease}, doi = {10.1016/j.nbd.2022.105798}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300629}, year = {2022}, abstract = {The pathogenesis of Parkinson's disease (PD) is closely interwoven with the process of aging. Moreover, increasing evidence from human postmortem studies and from animal models for PD point towards inflammation as an additional factor in disease development. We here assessed the impact of aging and inflammation on dopaminergic neurodegeneration in the hm\(^{2}\)α-SYN-39 mouse model of PD that carries the human, A30P/A53T double-mutated α-synuclein gene. At 2-3 months of age, no significant differences were observed comparing dopaminergic neuron numbers of the substantia nigra (SN) pars compacta of hm\(^{2}\)α-SYN-39 mice with wildtype controls. At an age of 16-17 months, however, hm\(^{2}\)α-SYN-39 mice revealed a significant loss of dopaminergic SN neurons, of dopaminergic terminals in the striatum as well as a reduction of striatal dopamine levels compared to young, 2-3 months transgenic mice and compared to 16-17 months old wildtype littermates. A significant age-related correlation of infiltrating CD4+ and CD8\(^{+}\) T cell numbers with dopaminergic terminal loss of the striatum was found in hm\(^{2}\)α-SYN-39 mice, but not in wildtype controls. In the striatum of 16-17 months old wildtype mice a slightly elevated CD8\(^{+}\) T cell count and CD11b\(^{+}\) microglia cell count was observed compared to younger aged mice. Additional analyses of neuroinflammation in the nigrostriatal tract of wildtype mice did not yield any significant age-dependent changes of CD4\(^{+}\), CD8\(^{+}\) T cell and B220\(^{+}\) B cell numbers, respectively. In contrast, a significant age-dependent increase of CD8\(^{+}\) T cells, GFAP\(^{+}\) astrocytes as well as a pronounced increase of CD11b+ microglia numbers were observed in the SN of hm\(^{2}\)α-SYN-39 mice pointing towards a neuroinflammatory processes in this genetic mouse model for PD. The findings in the hm\(^{2}\)α-SYN-39 mouse model strengthen the evidence that T cell and glial cell responses are involved in the age-related neurodegeneration in PD. The slow and age-dependent progression of neurodegeneration and neuroinflammation in the hm\(^{2}\)α-SYN-39 PD rodent model underlines its translational value and makes it suitable for studying anti-inflammatory therapies.}, language = {en} }