Implementation and the effects of a Parkinson Network Therapy (PaNTher) on activities of daily living and health-related quality of life in Parkinson's disease patients: study protocol of an mixed-method observational cohort study in outpatient care

INTRODUCTION

Parkinson's disease (PD) represents the fastest growing neurodegenerative disease with an increasing prevalence worldwide. It is characterised by complex motor and non-motor symptoms that lead to considerable disability. Specialised physiotherapy has been shown to benefit patients with PD. The Parkinson Netzwerk Therapie (PaNTher) was created to improve access to specialised physiotherapy tailored to care priorities of PD patients. This study aims to evaluate the effectiveness, acceptability and needs of the PaNTher network by neurologists and physiotherapists involved in the network in outpatient care.

METHODS AND ANALYSIS

This is a mixed-method, prospective, pragmatic non-randomised cohort study of parallel groups, with data collection taking place in Bavaria, Germany, between 2020 and 2024. Patients with PD insured by the Allgemeine Ortskrankenkasse Bayern (AOK Bayern) living in Bavaria will be recruited for study participation by network partners. Patients in the intervention group must reside in Munich or the surrounding area to ensure provision of specialised physiotherapy in close proximity to their place of residence. Controls receive care as usual. Six and 12 months after baseline, all patients receive a follow-up questionnaire. Mixed-effect regression models will be used to examine changes in impairment of activities of daily living and quality of life of patients with PD enrolled in the programme over time compared with usual care. Qualitative interviews will investigate the implementation processes and acceptability of the PaNTher network among neurologists and physiotherapists. The study is expected to show that the PaNTher network with an integrative care approach will improve the quality and effectiveness of the management and treatment of patients with PD.

ETHICS AND DISSEMINATION

The study has been approved by the ethics committee at the medical faculty of the Ludwig-Maximilians-University Munich (20-318). Results will be published in scientific, peer-reviewed journals and presented at national and international conferences.

Activities of Daily Living Are Improved by Inpatient Multimodal Complex Treatment for PD-a Real-World Cohort Study

Background

The multimodal complex treatment for Parkinson's disease (MCT) provides inpatient care by a multi-disciplinary team for people with Parkinson's disease (PwP) in Germany.

Objectives

We conducted a 5-year real-world mono-center cohort study to describe the effectiveness of MCT in the full cohort and various subgroups and outcome predictors.

Methods

We collected an anonymized dataset between Jan 2015 and Dec 2019, involving N = 1773. The self-reported MDS-UPDRS part II was used as primary outcome, and clinical routine data for explanatory variables. PwP were categorized as responders or non-responders according to a response of at least 3 points 4 weeks after discharge.

Results

N = 591 complete data records were available for statistical analyses. The full group improved by -2.4 points on the MDS-UPDRS II (P = <0.0001). 47.7% (n = 282) and 52.3% (n = 309) were coded as responders and non-responders, respectively. A clinically meaningful response was positively associated to age (χ² = 11.07, P = 0.018), as well as baseline-severity of the MDS-UPDRS II (χ² = 6.05, P = 0.048) and negatively associated to the presence of psychiatric disorder (χ² = 3.9, P = 0.048) and cognitive dysfunction (χ² = 7.29, P = 0.007). Logistic regression showed that baseline severity of the MDS-UPDRS II predicted therapy success. PwP with moderate baseline-severity had an about 2fold chance (OR 2.08; 95% CI 1.20-3.61; P = 0.009) and with severe an about 6fold chance (OR 5.92; 95% CI 2.76-12.68; P < 0.0001) to benefit clinically meaningful.

Discussion

In a naturalistic setting of a specialized Parkinson's center, MCT improved ADL disability of PwP at least 4 weeks after discharge. Moderately and severely impaired patients were more likely to achieve clinically meaningful responses.

Neurodevelopmental disorder with dystonia due to SOX6 mutations

BACKGROUND

Mutations in SOX6 have recently been recognized as a new molecular cause of neurodevelopmental disorders characterized by intellectual disability, behavioral changes, and nonspecific facial and digital skeletal abnormalities. To date, <25 cases have been reported in the literature.

METHODS AND FINDINGS

Here we report a new case of SOX6-associated neurodegeneration and expand the phenotype to include ceratoconus. The clinical picture consisted of early onset mildly reduced intellectual function, facial asymmetry, and dystonic tremor of hands and neck, substantially improved by levodopa. Skeletal abnormalities included scoliosis and hypertrophy of the mandibular coronoid process. A heterozygous de novo loss-of-function variant in SOX6 (c.277 C>T. p.Arg93*) was molecularly confirmed which leads to truncation of the SOX6 protein in its N-terminus, upstream of any known functional domain.

CONCLUSION

SOX6-associated neurodevelopmental delayis ultrarare with less than 25 cases described in the literature. We report a new case who presented with early-onset mildly reduced intellectual function, facial asymmetry, skeletal abnormalities and dystonic tremor of hands and neck, substantially improved by levodopa. Given the therapeutic implications, SOX6 mutations should be considered in patients with complex dystonia parkinsonism.

Effects of Low-Intensity Vestibular Noise Stimulation on Postural Instability in Patients with Parkinson's Disease

BACKGROUND

Postural instability is a major disabling factor in patients with advanced Parkinson's disease (PD) and often resistant to treatment. Previous studies indicated that imbalance in PD may be reduced by low-intensity noisy galvanic vestibular stimulation (nGVS).

OBJECTIVE

To investigate the potential mode of action of this therapeutic effect. In particular, we examined whether nGVS-induced reductions of body sway in PD are compatible with stochastic resonance (SR), a mechanism by which weak sensory noise stimulation can paradoxically enhance sensory information transfer.

METHODS

Effects of nGVS of varying intensities (0-0.7 mA) on body sway were examined in 15 patients with PD standing with eye closed on a posturographic force plate. We assumed a bell-shaped response curve with maximal reductions of sway at intermediate nGVS intensities to be indicative of SR. An established SR-curve model was fitted on individual patient outcomes and three experienced human raters had to judge whether responses to nGVS were consistent with the exhibition of SR.

RESULTS

nGVS-induced reductions of body sway compatible with SR were found in 10 patients (67%) with optimal improvements of 23±13%. In 7 patients (47%), nGVS-induced sway reductions exceeded the minimally important clinical difference (optimal improvement: 30±10%), indicative of strong SR. This beneficial effect was more likely in patients with advanced PD (R = 0.45; p = 0.045).

CONCLUSIONS

At least half of the assessed patients showed robust improvements in postural balance compatible with SR when treated with low-intensity nGVS. In particular, patients with more advanced disease stages and imbalance may benefit from the non-invasive and well-tolerated treatment with nGVS.

18F-PI-2620 Tau PET Improves the Imaging Diagnosis of Progressive Supranuclear Palsy

Progressive supranuclear palsy (PSP) is a 4-repeat tauopathy movement disorder that can be imaged by the ¹⁸F-labeled tau PET tracer 2-(2-([¹⁸F]fluoro)pyridin-4-yl)-9H-pyrrolo[2,3-b:4,5-c']dipyridine (¹⁸F-PI-2620). The in vivo diagnosis is currently established on clinical grounds and supported by midbrain atrophy estimation in structural MRI. Here, we investigate whether ¹⁸F-PI-2620 tau PET has the potential to improve the imaging diagnosis of PSP. Methods: In this multicenter observational study, dynamic (0-60 min after injection) ¹⁸F-PI-2620 PET and structural MRI data for 36 patients with PSP, 22 with PSP-Richardson syndrome, and 14 with a clinical phenotype other than Richardson syndrome (i.e., variant PSP) were analyzed along with data for 10 age-matched healthy controls (HCs). The PET data underwent kinetic modeling, which resulted in distribution volume ratio (DVR) images. These and the MR images were visually assessed by 3 masked experts for typical PSP signs. Furthermore, established midbrain atrophy parameters were measured in structural MR images, and regional DVRs were measured in typical tau-in-PSP target regions in the PET data. Results: Visual assessments discriminated PSP patients and HCs with an accuracy of 63% for MRI and 80% for the combination of MRI and ¹⁸F-PI-2620 PET. As compared with patients of the PSP-Richardson syndrome subgroup, those of the variant PSP subgroup profited more in terms of sensitivity from the addition of the visual ¹⁸F-PI-2620 PET to the visual MRI information (35% vs. 22%). In quantitative image evaluation, midbrain-to-pons area ratio and globus pallidus DVRs discriminated best between the PSP patients and HCs, with sensitivities and specificities of 83% and 90%, respectively, for MRI and 94% and 100%, respectively, for the combination of MRI and ¹⁸F-PI-2620 PET. The gain of sensitivity by adding ¹⁸F-PI-2620 PET to MRI data was more marked in clinically less affected patients than in more affected patients (37% vs. 19% for visual, and 16% vs. 12% for quantitative image evaluation). Conclusion: These results provide evidence for an improved imaging-based PSP diagnosis by adding ¹⁸F-PI-2620 tau PET to structural MRI. This approach seems to be particularly promising at earlier disease stages and could be of value both for improving early clinical PSP diagnosis and for enriching PSP cohorts for trials of disease-modifying drugs.

Voice Analysis to Differentiate the Dopaminergic Response in People With Parkinson's Disease

Humans' voice offers the widest variety of motor phenomena of any human activity. However, its clinical evaluation in people with movement disorders such as Parkinson's disease (PD) lags behind current knowledge on advanced analytical automatic speech processing methodology. Here, we use deep learning-based speech processing to differentially analyze voice recordings in 14 people with PD before and after dopaminergic medication using personalized Convolutional Recurrent Neural Networks (p-CRNN) and Phone Attribute Codebooks (PAC). p-CRNN yields an accuracy of 82.35% in the binary classification of ON and OFF motor states at a sensitivity/specificity of 0.86/0.78. The PAC-based approach's accuracy was slightly lower with 73.08% at a sensitivity/specificity of 0.69/0.77, but this method offers easier interpretation and understanding of the computational biomarkers. Both p-CRNN and PAC provide a differentiated view and novel insights into the distinctive components of the speech of persons with PD. Both methods detect voice qualities that are amenable to dopaminergic treatment, including active phonetic and prosodic features. Our findings may pave the way for quantitative measurements of speech in persons with PD.

The Minimal Clinically Relevant Change of the FOG Score

BACKGROUND

Freezing of gait is a highly disabling symptom in persons with Parkinson's disease (PwP). Despite its episodic character, freezing can be reliably evaluated using the FOG score. The description of the minimal clinically relevant change is a requirement for a meaningful interpretation of its results.

OBJECTIVE

To determine the minimal clinically relevant change of the FOG score.

METHODS

We evaluated video recordings of a standardized freezing-evoking gait parkour, i.e., the FOG score just before and 30 minutes after the intake of a regular levodopa dose in a randomized blinded fashion. The minimal clinically relevant response was considered a value of one or more on a 7-step Likert-type response scale [-3; +3] that served as the anchor. The minimal clinically relevant change was determined by ROC analysis.

RESULTS

37 PwP (Hoehn & Yahr stages 2.5-4, 27 male, 10 female) were aged 68.2 years on average (range 45-80). Mean disease duration was 12.9 years (2-29 years). Minimum FOG score was 0 and Maximum FOG score was 29. Mean FOG scores before medication were 10.6, and 11.1 after medication intake, with changes ranging from -14.7 to +16.7. The minimal clinically relevant change (MCRC) for improvement based on expert clinician rating was three scale points with a sensitivity of 0.67 and a specificity of 0.96.

CONCLUSIONS

The FOG score is recognized as a useful clinical instrument for the evaluation of freezing in the clinical setting. Knowledge of the MCRC should help to define responses to interventions that are discernible and meaningful to the expert physician and to the patient.

High-Resolution Motor State Detection in Parkinson's Disease Using Convolutional Neural Networks

Patients with advanced Parkinson's disease regularly experience unstable motor states. Objective and reliable monitoring of these fluctuations is an unmet need. We used deep learning to classify motion data from a single wrist-worn IMU sensor recording in unscripted environments. For validation purposes, patients were accompanied by a movement disorder expert, and their motor state was passively evaluated every minute. We acquired a dataset of 8,661 minutes of IMU data from 30 patients, with annotations about the motor state (OFF,ON, DYSKINETIC) based on MDS-UPDRS global bradykinesia item and the AIMS upper limb dyskinesia item. Using a 1-minute window size as an input for a convolutional neural network trained on data from a subset of patients, we achieved a three-class balanced accuracy of 0.654 on data from previously unseen subjects. This corresponds to detecting the OFF, ON, or DYSKINETIC motor state at a sensitivity/specificity of 0.64/0.89, 0.67/0.67 and 0.64/0.89, respectively. On average, the model outputs were highly correlated with the annotation on a per subject scale (r = 0.83/0.84; p < 0.0001), and sustained so for the highly resolved time windows of 1 minute (r = 0.64/0.70; p < 0.0001). Thus, we demonstrate the feasibility of long-term motor-state detection in a free-living setting with deep learning using motion data from a single IMU.

Interrelation between Sarcopenia and the Number of Motor Neurons in Patients with Parkinsonian Syndromes

INTRODUCTION

Pathogenesis in a subgroup of sarcopenic patients seems to be based on a reduced number of motor neurons. This study aimed at investigating the overlap between sarcopenia and neurodegeneration, as reflected by a low number of motor neurons in patients with Parkinsonian syndromes (PS).

METHODS

The motor unit number index (MUNIX) of the hypothenar muscle was used to assess the number and size (MUSIX) of motor units (MUs) in patients with idiopathic Parkinson disease (iPD, n = 53), patients with atypical Parkinsonian syndrome (aPS, n = 21), and a control group (n = 30). Mean age of participants was 70.3 years and 54.1% were female. Skeletal muscle mass by bioelectrical impedance analysis, hand-grip strength and gait speed were measured. Based on these assessments, sarcopenia was diagnosed according to the criteria of the European Working Group on Sarcopenia in Older People.

RESULTS

Sarcopenia criteria were met by 10 patients with PS (13.5%). The study group had significantly lower MUNIX values than the control group (109 [SD ±39.1] vs. 129 [SD ±45.1]; p = 0.020) even after adjustment for age and sex. Three of the 5 sarcopenic iPD patients (75%) had pathological low MUNIX values (<80).

DISCUSSION/CONCLUSION

Sarcopenia is a frequent comorbidity in PS. The pathologically low MUNIX values found in 75% of our sarcopenic iPD patients provides further support for the existence of a neurodegenerative overlap syndrome with a reduced number of MUs potentially leading to sarcopenia. This finding warrants further evaluation.

Gait festination in parkinsonism: introduction of two phenotypes

Gait festination is one of the most characteristic gait disturbances in patients with Parkinson’s disease or atypical parkinsonism. Although festination is common and disabling, it has received little attention in the literature, and different definitions exist. Here, we argue that there are actually two phenotypes of festination. The first phenotype entails a primary locomotion disturbance, due to the so-called sequence effect: a progressive shortening of step length, accompanied by a compensatory increase in cadence. This phenotype strongly relates to freezing of gait with alternating trembling of the leg. The second phenotype results from a postural control problem (forward leaning of the trunk) combined with a balance control deficit (inappropriately small balance-correcting steps). In this viewpoint, we elaborate on the possible pathophysiological substrate of these two phenotypes of festination and discuss their management in daily clinical practice.

Body height loss characterizes camptocormia in Parkinson's disease

Axial deformities such as camptocormia or Pisa syndrome in people with Parkinson's disease (PwP) are poorly understood. The scarcity of information may result from the shortage of reliable and responsive evaluation instruments. We evaluated the body height loss (BHL) as a new measure for PwP with axial deformities. 50 PwP with axial deformity defined by an UPDRS item 28 value of at least 2 were included in this mono-center study. We measured body height while lying supine and after 1 min of standing, providing a percentage value of BHL, and compared this measure to other clinical variables. BHL depended on the Hoehn and Yahr clinical stage and correlated with clinical scales for function and mobility, but not with timely measures of the axial disorder such as age at diagnosis or duration of disease. ANOVA showed that only lumbar flexion explained the variability of BHL (F = 21.0, p < 0.0001), but not kyphosis (F = 0.4, p = 0.74) or lateroflexion (F = 0.6, p = 0.6). Re-test reliability of BHL was good with к = 0.76 (p < 0.0001). BHL resulted from the lumbar spine and the hip joint and not from the thoracic spine or lateroflexion. This observation conforms to the concept of upper-type and lower-type camptocormia with only the latter leading to a BHL. The assessment of the BHL is shown to be a well defined, easy to perform, and reliable measure for the clinical evaluation of lower-type camptocormia.

Spatial constraints evoke increased number of steps during turning in Parkinson's disease

OBJECTIVE

Turning and limitations to step length were shown to trigger progressive shortening of steps, which can lead to freezing of gait. By reducing the base area in which the turn had to take place, we aimed to evaluate the contribution of spatial constraints on 360° axial turns in people with Parkinson's disease with and without freezing.

METHODS

We evaluated 40 patients with and without freezing and 16 age-matched healthy subjects. We assessed clinical data, and used body-worn inertial sensors to describe stepping and turn duration of 360° in quadratic squares of different sizes marked on the floor.

RESULTS

We found that, when subjects had to perform turns in smaller as compared to larger squares, this spatial constraint strongly affected the turning behavior, i.e. increased the number of steps, and the duration of turns. However, turning was significantly more impaired in patients as compared to controls, and patients with freezing were significantly worse as patients without freezing.

CONCLUSION

Our data show that spatial constraint during axial turning has the potential to deteriorate stepping performance, especially in patients reporting freezing of gait.

SIGNIFICANCE

The size of the base area needs to be defined in any item or scale that makes diagnostic use of turning.

Development and validation of a new screening questionnaire for dysphagia in early stages of Parkinson's disease

BACKGROUND

Dysphagia in patients with Parkinson's disease (PD) significantly reduces quality of life and predicted lifetime. Current screening procedures are insufficiently evaluated. We aimed to develop and validate a patient-reported outcome questionnaire for early diagnosis of dysphagia in patients with PD.

METHODS

The two-phased project comprised the questionnaire, diagnostic scales construction (N = 105), and a validation study (N = 82). Data for the project were gathered from PD patients at a German Movement Disorder Center. For validation purposes, a clinical evaluation focusing on swallowing tests, tests of sensory reflexes, and fiberoptic endoscopic evaluation of swallowing (FEES) was performed that yielded a criteria sum score against which the results of the questionnaire were compared. Specificity and sensitivity were evaluated for the detection of noticeable dysphagia and for the risk of aspiration.

RESULTS

The Munich Dysphagia Test - Parkinson's disease (MDT-PD) consists of 26 items that show high internal consistency (α = 0.91). For the validation study, 82 patients, aged 70.9 ± 8.7 (mean ± SD), with a median Hoehn & Yahr stage of 3, were assessed. 73% of patients had dysphagia with noticeable oropharyngeal symptoms (44%) or with penetration/aspiration (29%). The criteria sum score correlated positively with the screening result (r = 0.70, p < 0.001). The MDT-PD sum score classified not noticeable dysphagia vs. risk of aspiration (noticeable dysphagia) with a sensitivity of 90% (82%) and a specificity of 86% (71%), and yielded similar results in cross-validation, respectively.

CONCLUSIONS

MDT-PD is a valid screening tool for early diagnosis of swallowing problems and aspiration risk, as well as initial graduation of dysphagia severity in PD patients.

Randomized cross-over trial to investigate the efficacy of a two-week physiotherapy programme with repetitive exercises of cueing to reduce the severity of freezing of gait in patients with Parkinson’s disease

Objective:

To investigate the efficacy of a two-week programme of repetitive exercise with cueing and movement strategies upon freezing of gait in people with Parkinson’s disease.

Design:

Randomized cross-over trial.

Setting:

Specialist clinic for Parkinson’s disease.

Subjects:

A total of 22 patients with Parkinson’s disease and freezing while other symptoms had favorably responded to dopaminergic treatment.

Intervention:

Patients were randomized into a four-week cross-over trial, and received either treatment (Group 1) or no treatment (Group 2) during Period 1, and switched during Period 2. Treatment consisted of a two-week programme during which the patients exercised cueing, and movement strategies together with a physiotherapist.

Main measure:

The primary outcome measure was a freezing score assessed from blinded and random ratings of video recordings. The secondary outcome measure was a patient-reported freezing questionnaire. Mean differences between the treatment periods (treatment arms) were evaluated for treatment (period) effects. Sums of treatment periods were evaluated for carry-over effects.

Results:

The programme led to a significant treatment effect in the freezing score of 3.0 improvement (95% confidence interval 0.9–5.0; p < 0.01). No carry-over or period effects were detected. The questionnaire revealed a period effect, so groups were compared after Period 1, where a significant difference was found (15.0 vs. 11.7; p < 0.05).

Conclusions:

The two-week physiotherapy programme reduced the severity of freezing in patients with Parkinson’s disease.

Early botulinum toxin treatment for spastic pes equinovarus--a randomized double-blind placebo-controlled study

BACKGROUND AND PURPOSE

Spastic pes equinovarus is a frequent pathological posture of the lower extremity. Botulinum toxin (BoNT/A) has been successfully applied to treat lower limb spasticity. However, the best time to initiate treatment remains unclear. A beneficial effect of an early treatment has been suggested in previous studies.

METHODS

A single-centre double-blind randomized placebo-controlled trial was performed to investigate the efficacy of BoNT/A to reduce muscle hypertonicity at the ankle. Fifty-two patients with unilateral or bilateral spastic pes equinovarus with a modified Ashworth score (mAS) of at least 1+ after stroke, traumatic brain injury or hypoxic encephalopathy were allocated to receive either BoNT/A or placebo treatment. A second, open injection was optional at week 12. Patients received unilateral or bilateral injections with 230 or 460 U onabotulinumtoxinA, respectively. The course of the mAS was explored during the open study phase.

RESULTS

Patients who had received BoNT/A treatment had lower mAS compared with placebo at week 12 (P < 0.01). During the open label phase, patients from the placebo group showed further deterioration of muscle tone despite starting from a similar baseline and receiving BoNT treatment. Spastic feet that had received BoNT/A in the first cycle had comparatively lower mAS scores over all follow-up data and at week 24 (P < 0.01).

CONCLUSIONS

The study demonstrates a reduction of muscular hypertonicity in spastic pes equines with BoNT/A treatment given during the first 3 months after the lesion. Exploratory analyses of the course of muscular hypertonicity during the open phase favour earlier to later treatment.

Muscle atrophy beyond the clinical effect after a single dose of OnabotulinumtoxinA injected in the procerus muscle: a study with magnetic resonance imaging

BACKGROUND

Botulinum toxin is a powerful and often used agent to treat dynamic rhytides. Focal and reversible neurogenic atrophy is considered to be the relevant mechanism of action.

OBJECTIVE

To investigate the loss and regain of muscular volume in relation to clinical wrinkle severity as assessed using standardized scales.

METHODS

The facial procerus and corrugator supercilii muscles were injected in two drug-naïve men with 20 U of onabotulinumtoxinA at five injection points (onA). Two men served as controls (one with the same volume of placebo injection using saline solution, one without any intervention). All subjects underwent 3 Tesla magnetic resonance imaging before and after the injection and 1, 4, 6, 10, and 12 months after the injection. Standardized photographs were taken at each test point.

RESULTS

Volumetric muscle analysis revealed a 46% to 48% reduction in procerus muscle volume lasting for 12 months after a single dose of onA; glabellar line severity returned to the drug-naïve status after 6 to 10 months.

CONCLUSION

The gap between long-term focal muscular atrophy and regained function remains to be elucidated. Future studies will be needed to investigate the complex interaction between focal neurogenic atrophy and potential compensatory functional muscle changes.

A novel wearable laser device to regulate stride length in Parkinson's disease

Decreased stride length is a highly relevant characteristic of the gait in patients with Parkinson's disease (PD). In this paper, a novel wearable laser device for stride length regulation is presented. The device is mounted to one foot and can project a red laser light strip to the floor as a visual cue for the other foot. In the experiment twelve healthy volunteers walked a 20 m straight walkway wearing the system on both feet. As an objective result, the stride length regulation reached an accuracy of 96.1 ± 2.5 (94.0 ± 3.5) % for a pre-defined stride length λdef= 55 (65) cm. The subjective evaluation by the participants using a questionnaire revealed that the visual cue projected from the laser device was considered a stable signal that did not shake during walking. 6 of 12 participants felt that this device was not interfering with their gait, 3 of 12 judged this aspect neutrally, and 3 of 12 considered it somehow bothersome.

A new rating instrument to assess festination and freezing gait in Parkinsonian patients

Festination and freezing of gait (FOG) are sudden episodic inabilities to initiate or sustain locomotion mostly experienced during the later stages of Parkinson's disease (PD) or other higher-level gait disorders. The aim of this study was to develop a clinical rating instrument for short-interval rating of festination and FOG. Foot movements of 33 patients were video taped and rated during 12 episodes in a standardized course on a four-level interval scale according to severity. Motor blocks were provoked in four situations and by three levels of dual-tasking (tasks). Addition of the item scores produced a FOG score. The assessment requires less than 15 min. The inter-rater and re-test reliability of the FOG score is high (Kendall kappa = 0.85-0.92, P < 0.0001). Variability of the item scale due to situations and tasks can be attributed to unidimensional group factors (Cronbach's alpha 0.84 and 0.94). Group comparisons and a logistic regression model show significant effects for both situations and tasks on the item scale (Friedman test: "situation": P < 0.0001, "task": P < 0.0001). Six patients with PD have significantly different scores during mobile (practical ON; 6.2 +/- 3.9) and immobile (practical OFF; 15.8 +/- 4.6) medication states (P < 0.05). The FOG score correlates with the 10 m number of steps (rho = 0.58; P = 0.001) and with the self-evaluation of FOG (rho = 0.51; P < 0.01). Our results encourage the further use of the FOG score to evaluate festination and FOG.

Maturation of inhibitory and excitatory motor cortex pathways in children

OBJECTIVE

To study intracortical inhibition and facilitation with paired-pulse transcranial magnetic stimulation in children, adolescents and adults.

METHODS

Paired-pulse transcranial magnetic stimulation (interstimulus intervals (ISI): 1, 3, 5, 10 and 20 ms) was applied over the primary motor cortex (M1) in 30 healthy subjects (range 6-30 years, median age 15 years and 8 months, SD 7,9) divided in three groups: adults (>or=18 years), adolescents (> 10 and < 18 years) and children (<or=10 years).

RESULTS

We observed significantly less intracortical inhibition (SICI) in children's M1 compared to that of adults. Adolescents showed significantly less SICI at the 5 ms interval than did adults. No significant differences were apparent in intracortical facilitation (ICF).

CONCLUSION

We postulate that, as in adults, the maturing M1 possesses horizontal glutamatergic cross-links that represent the neuronal substrate of excitatory intracortical pathways. GABAergic interneurons, the neuronal substrate of inhibitory intracortical pathways, mature between childhood and adulthood. Reduced GABAergic inhibition may facilitate neuronal plasticity and motor learning in children.

Canalicular magnetic stimulation lacks specificity to differentiate idiopathic facial palsy from borreliosis in children

OBJECTIVE

To investigate the role of transcranial magnetic stimulation (TMS) to differentiate between idiopathic facial nerve palsy (iFNP) and facial nerve palsy due to borreliosis (bFNP).

PATIENTS AND METHODS

Transcranial and intracanalicular magnetic and peripheral electrical stimulation of the facial nerve together with clinical grading according to the House and Brackmann scale were performed in 14 children and adolescents with facial palsy (median age 11.5 yr, range 4.6-16.5 yr). Serum and cerebrospinal fluid (CSF) were evaluated for antibodies against Borrelia burgdorferi and CSF cell count, glucose and protein content were screened with methods of routine laboratory testing. Data of patients were compared with normal values established in 10 healthy subjects (median age 10.2 yr, range 5.1-15.3 yr).

RESULTS

Patients with iFNP showed a significant decrease in MEP amplitude to canalicular magnetic stimulation compared with healthy controls (p=0.03). However, MEP amplitude did not discriminate sufficiently between the two groups, because the ranges of dispersion of MEP amplitudes overlapped. Patients with bFNP had normal MEP amplitudes to canalicular magnetic stimulation compared with normal subjects.

CONCLUSION

Diagnostic assessment by TMS failed to provide a reliable diagnostic criterion for distinguishing between iFNP and bFNP in children and adolescents.

Botulinum toxin B treatment in children with spastic movement disorders: a pilot study

The treatment of adult and pediatric patients suffering from movement disorders with elevated muscle tone includes the application of focally denervating botulinum toxins. Dystonic movement disorders in adult patients have been treated successfully using botulinum toxin type B (NeuroBloc). Thus far, there has been no systematic treatment of children with botulinum toxin type B. This study reports on the treatment of 29 children with spastic or dystonic movement disorders using botulinum toxin type B in an open-label pilot study. Sixty-two treatment sessions were performed. In 33 of these sessions, the therapy goal that had been defined before intervention was attained or surpassed. Seventeen nonresponders to botulinum toxin type A were also included in the treatment, 11 of whom attained the therapy goal. Side effects were observed in 24% of all treatments, dry mouth being the most frequent (10%), in some cases having a desirable clinical effect. With this preliminary data as a basis, we recommend a maximum dose for children of 400 U botulinum toxin type B per kg body weight, which should not exceed a total of 10,000 U botulinum toxin type B.

Clinical impact of antibody formation to botulinum toxin A in children

We studied the clinical impact of neutralizing antibodies to botulinum toxin A that occurred during long-term treatment of children between 1993 and 2001. Antibodies were found in high titers in 35 of 110 (31.8%) samples from individual patients. Antibody formation correlated with secondary nonresponse (p < 0.001). The most significant risk factors for antibody formation were the frequency of treatments (p = 0.0001) and the injection of a higher weight-adapted maximum dose per treatment (p = 0.001).

Low level of intracortical inhibition in children shown by transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) is an established neurophysiological tool to evaluate the integrity and maturation of the corticospinal tract. TMS was used in this study to compare intracortical inhibition (ICI) in children, adolescents, and adults. The paired-pulse technique of TMS with interstimulus intervals of 2 ms was used to determine the ratio of conditioned (cMEP) and unconditioned amplitudes (ucMEP) that measures ICI. In experiment 1 (Exp 1) stimulus intensity was adapted to motor threshold (50 healthy subjects; 24 male, 26 female, median age 13.5 years, range 6.3 - 34 years) and in experiment 2 (Exp 2) stimulus intensity was adapted to the ucMEP (200 - 400 microV). Children (quotient of cMEP and ucMEP: Exp. 1: 0.71 +/- 0.41, Exp. 2: 0.82 +/- 0.25) had significantly less ICI compared to adults (Exp. 1: 0.21 +/- 0.19, mean +/- STD, Exp. 2: 0.35 +/- 0.22, in both experiments p < 0.001). Recently, ICI has been linked to the regulating function of GABAergic cortical interneurons on practice-dependent neuronal plasticity. Therefore, the lower ICI in children points to maturation processes that may have implications for the greater capacity of practice-dependent neuronal plasticity in children.

Methylphenidate enhances both intracortical inhibition and facilitation in healthy adults

Transcranial magnetic stimulation was used to investigate the effect of the psychostimulant drug methylphenidate (MPH) on motor cortex excitability in healthy adults (n = 12) in a placebo-controlled, crossover design study. MPH caused an enhancement of intracortical inhibition as well as intracortical facilitation. Enhancement of both of these TMS parameters was unexpected and suggests that MPH exerts its action on the motor cortex not only through the dopaminergic neurotransmitter system.

Development of the corticospinal system and hand motor function: central conduction times and motor performance tests

Maturation of the corticospinal (CS) tract and hand motor function provide paradigms for central nervous system development. In this study, involving 112 participants (aged from 0.2 to 30 years), we evaluated central motor conduction times (CMCT) obtained with transcranial magnetic stimulation (TMS) during preinnervation conditions of facilitation and relaxation. Auditory reaction time, velocity of a ballistic movement of the arm, finger tapping, diadochokinesis, and fine motor visuomanual tracking were also examined. The maturation profiles for every parameter were calculated. CMCTs for the different preinnervation conditions reached adult values at different times and this could be explained by maturation of excitability at the cortical and spinal level. A stable phase for CMCTs and reaction time was reached during childhood. Parameters which measured motor speed and skill indicated that the development of these continued into adulthood. The maturation of the fast CS tract seems to be completed before the acquisition of the related motor performance has been accomplished. In conclusion, we could demonstrate that data from several neurophysiological methods can be combined and used to study the maturation of the function of the nervous system. This approach could allow appraisal of pathological conditions that show parallels with omissions or lack of developmental progress.

Fast corticospinal system and motor performance in children: conduction proceeds skill

Transcranial magnetic stimulation and motor performance tests were used to study the correlation between corticospinal maturation and actual motor performance in a group of young school children (n = 10, mean age = 7 years, age range = 6-9 years). The results were compared with normal adults (n = 10, mean age = 24 years, age range = 22-26 years). In children the central conduction time under the preinnervation condition of facilitation and the postexcitatory silent period was similar to that in adults. However, the central conduction time under relaxation, the latency jump (defined as the difference between the two preinnervation conditions), and the stimulus intensity were statistically different between children and adults (P < 0.01-0.001). Children did not reach the same level of performance as adults in any of the motor performance tasks (simple acoustic reaction time, tapping, ballistic movement, tracking, and diadochokinesis) (P < 0.05-0.01). The results indicate that at an early school age, children already possess mature fast corticospinal pathways able to access spinal motoneurons through the pyramidal tract. However, despite the partially adult-like level of neuronal maturation, young school children were not able to perform deliberate motor actions with the same proficiency as adults.