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Introduction. In this study we evaluated the autonomic neural function in Parkinson's disease (PD) by combining the use of clinical scoring, functional evaluation with head-up tilt test (HUTT) and morphological studies of the vagus nerve (VN) with nerve ultrasound (NU). This allowed us to correlate morphological changes of the VN with markers of parasympathetic dysfunction from HUTT. Patients/Methods. In our study we used NU to compare the mean values of the cross-sectional area (CSA) of the VNs of 80 PD patients with those of controls (n=40) and patients with chronic inflammatory demyelinating polyneuropathy (CIDP) (n=76). In 69 cases HUTT data was analyzed concerning the presence of orthostatic hypotension (OH), postural orthostatic tachycardia syndrome (POTS) and chronotropic incompetence (CI). Functional haemodynamic parameters in HUTT were used to evaluate parasympathetic functions and correlate them with VN CSA (n=65). Results. In PD, the CSA of right / left VN was significantly smaller compared to the right/left VN of the control and CIDP patients (Table 1). Based on HUTT, 60.5 % of the patients were diagnosed with autonomic dysfunction (OH n=11, CI n=31, POTS n=1). Patients with OH showed significantly higher UPDRS-III values than those with CI (p=0.025). The CSA of the VN correlated inversely with heart rate and positively with parameters representing parasympathetic modulation through vagal activity (Fig. 1). Conclusion. By using NU significant morphological differences of the CSA of the VN were detected in CIDP, PD and a healthy control group. Furthermore, we demonstrated for the first time that anatomical characteristics of the VN correlate with parameters of parasympathetic function from the spectral analysis of cardiovascular parameters in HUTT for PD. This finding enables a new interpretation of the anatomical characteristics of the VN for PD patients and diagnosis of autonomic dysfunction. Fig. 1. Schematic presentation of the inverse correlation of the cross-sectional area of the right vagus nerve with the heart rate. Positive correlation with markers of parasympathetic activity HFnu-RRI. (Spearman Correlation). Abbreviations: HR=heart rate, HFnuRRI = high frequency power of the RR-Interval, bpm= beats per minute, CSA= cross-sectional area Table 1. Demographical and epidemiological characteristics as well as the cross-sectional area (CSA) of the vagus nerve. All values are provided as mean ± standard deviation. Abbreviations: INCAT/ODSS = inflammatory neuropathy cause and treatment/overall disability sum score, MDS-UPDRS III= MDS-Unified Parkinson's Disease Rating Scale, SCOPA-AUT= Scales for Outcomes in Parkinson's Disease- Autonomic Dysfunction, PDQ39 = Parkinson's Disease Questionnaire, CSA = cross sectional area.

Background. Nerve conduction studies represent the gold standard in the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) and play a central role in the EFNS/PNS criteria. However, the highly extensive examination protocol of those criteria and the question how to further monitor are relevant problems in daily medical practice. Hence, the aim of this cross-sectional study is to establish a practical and applicable strategy a) conducting the EFNS/PNS criteria and b) monitoring disease related disability in a large cohort of CIDP patients. Methods. As part of a prospective cohort study, we conducted a bilateral neurographic examination of the median nerve (mot.+sens.), ulnar nerve (mot.+sens.), radial nerve (sens.), tibial nerve (mot.), peroneal nerve (mot.+sens.), and sural nerve (sens.) in 95 CIDP patients. The EFNS/PNS criteria were applied on the collected neurographic data and compared with the INCAT overall disability sum score (INCAT-ODSS) and INCAT sensory score (ISS) to quantify disease disabilities. Results. In total, 95 CIDP patients (f:m 1:3.32; mean age 59±12y; 52% atypical CIDP; mean disease duration 74±60 months) were recruited, thereof 25 at initial diagnosis. All patients fulfilled the electrophysiological EFNS/PNS diagnosis criteria for CIDP. At initial diagnosis, the median nerve met the single parameters of the EFNS/PNS criteria most frequently with 72%, followed by the tibial nerve with 66%, ulnar nerve with 46%, and peroneal nerve with 22%. In total, the criterion of prolonged distal cMAP duration was met most frequently (32%), followed by an abnormal temporal dispersion (16%) and absence of F-waves (13%). However, we identified axonal damage as the parameter related with clinical disability (p Conclusions. Although the majority of CIDP patients reveal symptoms predominant of the legs, the examination of the upper limbs has proven to be essential for both initial diagnosis and disease monitoring, underlining CIDP as a systemic disease. Especially the determination of the distal cMAP duration was a sensitive parameter in the detection of CIDP. The total disability is largely determined by the degree of axonal damage. Therefore, neuroprotection should have an important additional role in the CIDP therapy in the future.

Introduction. Previous studies have shown a high prevalence of up to 55% of axonal polyneuropathy (PNP) in patients with Parkinsons disease (PD), for which the causes are not certainly identified (Toth et al. 2010; Szadjeko et al. 2016). Our recent study with 50 PD patients also suggests correlations between findings in the nerve conduction studies (NCS) and clinical severity (Kuhn, Averdunk et al. 2020). By means of a lager cohort and extended NCS in this study, we aimed to characterise electrophysiological characteristics of PNP in PD patients. Methods. Nerve conduction studies, Hoehn&Yahr Scores and MDS-UPDRS Scores of 85 PD patients were evaluated. The cohort consisted of 49 men and 36 women, mean age was 68 ± 11 years, mean duration of disease was 6±5 years. Motor studies of tibial and median nerve and sensory studies of sural and median nerve were performed bilaterally in all patients and additional NCS of the fibular nerve, the ulnar nerve and the radial nerve were performed in 29 of the 85 patients. The NCS findings were analysed based on cut off normal values defined by Stohr et. al. 2012 (Table 1), and were divided into five subgroups depending on the severity of peripheral nerve impairment. We further analysed correlations between the NCS and the PD symptom scores Hoehn&Yahr and MDS-UPDRS III. Results. According to our findings, 25 patients (24,9%) showed no signs of peripheral nerve impairment (group 0), 8 patients (9,4%) were diagnosed with a mild sensory PNP with sole axonal impairment of the fibular nerve (group 1a), 21 patients (24,7%) were diagnosed with a mild sensory PNP with reduced sNAP of fibular and sural nerve (group 1b), 17 patients (20%) were diagnosed with a moderate sensorimotor PNP with reduced amplitudes of tibial (group 3), sural and fibular nerve and 15 patients (17,6%)showed signs of a severe sensorimotor PNP with impairment of the nerves in lower and upper extremities (group 3). Strong inverse correlations were found between tibial cMAP (r = −0,174, p = 0,042), sural sNAP (r = −0,219, p = 0,01) and radial sNAP (r = −0,383, p = 0,019) and MDS-UPDRS III scores independent of patients age and duration of disease. The tibial cMAP was significantly lower in late Hoehn&Yahr stages compared to earlier stages (8,9±4,4 vs 6,6±4,7 mV, p Conclusion. Our findings could verify the results found in our recent study with a larger cohort that the severity of PNP correlates with the clinical severity of PD. Longitudinal examination is required to show dynamic alterations and if peripheral nerve impairment can be used as a predictor for clinical burden in PD patients. Table 1. mean values of examined nerve response amplitudes.