Changes in corticospinal excitability have been well documented in the preparatory period before movement, however, their mechanisms and physiological role have not been entirely elucidated. We aimed ...to investigate the functional changes of excitatory corticospinal circuits during a reaction time (RT) motor task (thumb abduction) in healthy subjects (HS). 26 HS received single pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). After a visual go signal, we calculated RT and delivered TMS at three intervals (50, 100, and 150 ms) within RT and before movement onset, recording motor evoked potentials (MEP) from the abductor pollicis brevis (APB) and the task-irrelevant abductor digiti minimi (ADM). We found that TMS increased MEP
APB
amplitude when delivered at 150, 100, and 50 ms before movement onset, demonstrating the occurrence of premovement facilitation (PMF). MEP increase was greater at the shorter interval (MEP
50
) and restricted to APB (no significant effects were detected recording from ADM). We also reported time-dependent changes of the RT and a TMS side-dependent effect on MEP amplitude (greater on the dominant side). In conclusion, we here report changes of RT and side-dependent, selective and facilitatory effects on the MEP
APB
amplitude when TMS is delivered before movement onset (PMF), supporting the role of excitatory corticospinal mechanisms at the basis of the selective PMF of the target muscle during the RT protocol.
Purpose
To compare the incremental diagnostic value of amyloid-PET and CSF (Aβ42, tau, and phospho-tau) in AD diagnosis in patients with mild cognitive impairment (MCI) or mild dementia, in order to ...improve the definition of diagnostic algorithm.
Methods
Two independent dementia experts provided etiological diagnosis and relative diagnostic confidence in 71 patients on 3 rounds, based on (1) clinical, neuropsychological, and structural MRI information alone; (2) adding one biomarker (CSF amyloid and tau levels or amyloid-PET with a balanced randomized design); and (3) adding the other biomarker.
Results
Among patients with a pre-biomarker diagnosis of AD, negative PET induced significantly more diagnostic changes than amyloid-negative CSF at both rounds 2 (CSF 67%, PET 100%,
P
= 0.028) and 3 (CSF 0%; PET 78%,
P
< 0.001); PET induced a diagnostic confidence increase significantly higher than CSF on both rounds 2 and 3.
Conclusions
Amyloid-PET should be prioritized over CSF biomarkers in the diagnostic workup of patients investigated for suspected AD, as it provides greater changes in diagnosis and diagnostic confidence.
Trial registration
EudraCT no.: 2014-005389-31
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
Camptocormia is characterized by a pathological forward flexion of the trunk, which is reversible when lying and worsened by standing and walking. So far there is no consensus on how to measure the ...angle of flexion, and studies therefore give differing results. Harmonization is needed for both research and clinical practice. Orthopedic measures are not useful for this purpose.
Two expert raters independently analyzed the photographs of 39 Parkinson patients with camptocormia while standing. They used four different methods to determine the camptocormia angle. The results were compared statistically. An international Consensus Group reviewed the results and drafted recommendations.
The four methods yielded camptocormia angles that differed by up to 50% in the same patient. Inter-rater reliability and test-retest reliability also differed, but were satisfactory to excellent.
This Consensus Group concluded that two of the methods qualified as reliable measures of the trunk angles in standing patients based on their clinimetric properties. They propose that the ‘total camptocomia angle’ be the angle between the line from the lateral malleolus to the L5 spinous process and the line between the L5 spinous process and the spinous process of C7. They also propose that the ‘upper camptocormia angle’ be the angle of the lines between the vertebral fulcrum to the spinous processes of L5 and C7, respectively. An app is provided on the web for these measurements (http://www.neurologie.uni-kiel.de/de/axial-posturale-stoerungen/camptoapp).
•There is no agreement on how to measure the camptocormia angle. Therefore studies on camptocormia are not comparable.•In this paper four different methods of angle assessment were empirically evaluated regarding reliability and face validity.•A consensus could be reached to measure a total camptocormia angle and an upper camptocormia angle.•Apps are available to measure these angles (http://www.neurologie.uni-kiel.de/de/axial-posturale-stoerungen/camptoapp).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Camptocormia is a disabling complication of Parkinson's disease (PD), but its pathophysiology is poorly elucidated. Depending on the fulcrum of forward trunk flexion, two subtypes have been defined, ...upper (UCC) and lower camptocormia, the former being much more frequent. The aim of the study was to explore possible pathophysiological mechanisms of PD-related UCC.
Ten PD patients with UCC (UCC-PD) and ten PD patients without camptocormia (NoUCC-PD) underwent simultaneous electromyography (EMG) of thoracic paraspinal (TPS), obliquus externus abdominis (OEA), rectus abdominis (RA), and iliopsoas (IP) muscles during relaxed standing (both groups) and trunk realignment (UCC-PD group). Quantitative EMG and magnetic resonance imaging (MRI) of TPS muscles were also performed.
UCC-PD patients showed hyperactivity of TPS and OEA muscles in quiet stance. During voluntary trunk extension, hyperactivity of OEA muscles persisted, thus revealing a co-contraction of flexor and extensor trunk muscles. Motor unit potentials (MUP) of TPS muscles showed shorter duration (p = 0.005) and lower amplitude (p = 0.004) in UCC-PD than in NoUCC-PD patients. MRI did not detect significant between-group differences in the cross-sectional area and fat fraction of TPS muscles, although the latter was higher in the UCC-PD than in the NoUCC-PD group at all thoracic levels.
Our findings suggest that hyperactivity of OEA might sustain UCC in PD. Concurrent mild myopathic changes in TPS muscles in PD with UCC may be secondary to muscle disuse but nevertheless may contribute to abnormal trunk posture.
•Co-contraction of antagonistic trunk muscles exists in upper camptocormia.•Obliquus externus muscles play a crucial role in upper camptocormia.•Thoracic paraspinal muscles show subtle myopathic EMG changes in upper camptocormia.•Central and peripheral patomechanisms contribute to PD-related upper camptocormia.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lateral trunk flexion (LTF) and its severe form, called Pisa syndrome (PS), are highly invalidating axial postural abnormalities associated with Parkinson’s disease (PD). Management strategies for ...LTF lack strong scientific evidence. We present a real-life, longitudinal study evaluating long-term efficacy of botulinum toxin (BoNT) injections in axial muscles to reduce LTF and PS in PD. A total of 13 PD patients with LTF > 5° received ultrasound- and electromyography-guided BoNT injections every 4 months. Seven untreated matched PD patients with LTF served as controls and their changes in posture after 18 months were compared with those of seven patients continuing BoNT over 12 months. 53.8% of patients continued the BoNT injections for at least 12 months. Various individual LTF responses were observed. Overall, BoNT-treated patients obtained a not statistically significant improvement of LTF of 17 ± 41% (p = 0.237). In comparison, the seven untreated PD patients suffered a deterioration in LTF over 12 months by 36 ± 45% (p = 0.116), showing a significantly different trajectory of posture change (p = 0.026). In conclusion, repeated BoNT injections in axial muscles showed varying effects in managing PD-associated LTF, suggesting that: (a) a relevant number of patients with LTF can benefit from BoNT; (b) long-term treatment could prevent LTF worsening; (c) an instrumented, personalized approach is important; and (d) there is a need for prospective, long-term studies.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The mechanisms underlying pain in Parkinson’s disease (PD) are unclear. Although a few studies have reported that PD patients may have low pain threshold and tolerance, none could accurately assess ...whether there was a correlation between sensory thresholds and demographic/clinical features of PD patients. Thus, tactile threshold, pain threshold, and pain tolerance to electrical stimuli in the hands and feet were assessed in 106 parkinsonian patients (of whom 66 reported chronic pain) and 51 age- and sex-matched healthy subjects. Linear regression models determined relationships between psychophysical parameters and demographic/clinical features. Female gender, severity of disease, medical disease associated with painful symptoms, and dyskinesia were more frequently observed in PD patients experiencing pain, even though dyskinesia did not reach significance. Pain threshold and pain tolerance were significantly lower in PD patients than in control subjects, whereas the tactile threshold yielded comparable values in both groups. Multivariable linear regression analyses yielded significant inverse correlations of pain threshold and pain tolerance with motor symptom severity and Beck depression inventory. Pain threshold and pain tolerance did not differ between PD patients with and without pain. In the former group, there was no relationship between pain threshold and the intensity/type of pain, and number of painful body parts. These findings suggest that pain threshold and pain tolerance tend to decrease as PD progresses, which can predispose to pain development. Female gender, dyskinesia, medical conditions associated with painful symptoms, and postural abnormalities secondary to rigidity/bradikinesia may contribute to the appearance of spontaneous pain in predisposed subjects.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Non-invasive brain stimulation (NIBS) techniques are used in clinical and cognitive neuroscience to induce a mild magnetic or electric field in the brain to modulate behavior and cortical activation. ...Despite the great body of literature demonstrating promising results, unexpected or even paradoxical outcomes are sometimes observed. This might be due either to technical and methodological issues (e.g., stimulation parameters, stimulated brain area), or to participants’ expectations and beliefs before and during the stimulation sessions. In this narrative review, we present some studies showing that placebo and nocebo effects, associated with positive and negative expectations, respectively, could be present in NIBS trials, both in experimental and in clinical settings. The lack of systematic evaluation of subjective expectations and beliefs before and after stimulation could represent a caveat that overshadows the potential contribution of placebo and nocebo effects in the outcome of NIBS trials.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•Functional Movement Disorders (FMDs) might exacerbate in stressful conditions.•Recurrent waves of Covid-19 could represent triggers and worsen FMDs symptoms.•In a follow-up study we compared FMDs ...symptoms after first and third Covid-19 waves.•Unexpectedly, patients showed stability through time.•Pain resulted as a predictor factor for the worsening of motor symptoms severity.
Functional Movement Disorders (FMDs) might exacerbate in stressful conditions. As the global health emergency due to Covid-19 rise and multiple waves hit the Italian population, the recurrent severe restrictions’ periods imposed could represent important triggers and worsen the symptoms of FMDs. Through a follow-up study, we compare results on Motor Symptoms (MS), Non-Motor Symptoms (NMS), and Global Health Status (GHS) of two surveys, one referred to the first Covid-19 wave and the other to the third Covid-19 wave.
60 FMDs patients responded to an online survey after the first and the third Covid-19 waves in Italy. Questions regarding sociodemographic, clinical and Covid-19 information, MS, NMS, and GHS were collected to assess severity of symptoms and changes in comparison to a period with less severe social restrictions.
Patients showed minimal to mild motor symptoms’ severity, and substantial stability through time in all collected measures, both for severity and changes of MS, NMS, and GHS in comparison at two time points (p > 0.050). The worsening of pain resulted as predictor factor for the worsening of Motor Symptoms (p = 0.042).
Patients did not show a vulnerability due to the recurrent restrictions’ periods: MS, NMS and GHS did not vary in comparison to the first wave, confirming the previous results and highlighting the role of the social context in those disorders. Further investigations are required to better disentangle the relationship between stressful events, motor symptoms, and pain.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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