Diagnostic accuracy of voluntary and stimulated neuromuscular jitter studies in ocular myasthenia gravis.

INTRODUCTION/AIMS: There is a lack of studies comparing the accuracy of neuromuscular jitter analysis during voluntary activation (v-jitter study) versus axonal stimulation (s-jitter study). The study aimed to compare these two techniques in the same population of patients with suspected ocular myasthenia gravis (OMG). METHODS: Fourteen control subjects (mean age: 55.5 ± 15.2 years) and 34 patients with suspected OMG (mean age: 59 ± 13.9 years) were prospectively evaluated. Twenty spike pairs and 30 individual spikes were analyzed during v-jitter and s-jitter study, respectively. Two different criteria for abnormal individual jitter values were evaluated: ≥ or > than 10% values exceeding the upper normal limit. RESULTS: OMG was diagnosed in 19 patients based on clinical and laboratory findings, without considering jitter measurements. In most patients, v-jitter and s-jitter analyses provided comparable results. The maximum sensitivity (89%) was achieved with s-jitter study using the ≥10% criterion, while the maximum specificity (93%) was found with v-jitter study using the >10% criterion. DISCUSSION: Both v-jitter and s-jitter studies showed good to very good accuracy for the diagnosis of OMG, in the absence of any statistically significant difference. Therefore, the patient's cooperation level and examiner's experience should guide the choice of performing v-jitter or s-jitter analysis in patients with suspected OMG.

The district operation centres in one of the largest local health authorities in Italy to manage COVID-19 surveillance and homecare: first implementation and results of a survey addressed to general practitioners.

BACKGROUND: COVID-19 pandemic represented a shock for healthcare systems. Italy was one of the first country to deal with a huge number of patients to be diagnosed, isolated, and treated with scarce evidence-based guidelines and resources. Several organizational and structural changes were needed to face the pandemic at local level. The article aims at studying the perceived impact of the newly implemented District Operation Centres (DOCs) of Local Health Authority (LHA) Roma 1 in managing active surveillance and home care of COVID-19 patients and their close contacts in cooperation with general practitioners (GPs). METHODS: A questionnaire, developed according to Delphi methodology, was validated by 7 experts and administered to a randomized sample of GPs and family paediatricians (FPs). All medical doctors selected received a phone interview between December 2020 and January 2021. The questionnaire investigated general characteristics of the sample, relations with DOC and its usefulness, and potential developments. A descriptive analysis was performed and inferential statistical tests were used to assess differences. RESULTS: In April 2020 the LHA Roma 1 implemented one DOCs in each local health district. 215 medical doctors were interviewed, reaching the sample target for health districts (80% CL and 10% MOE) and the whole LHA (90% CL and 5% MOE). Several aspects in the management of COVID-19 cases and close contacts of COVID-19 cases, and of the support of DOCs to GPs/FPs were investigated. More than 55% of the GPs and FPs interviewed found the DOCs useful and more than 78% would recommend a service DOC-like to other LHAs. The medical professionals interviewed would use DOCs in the future as support in treating vulnerable patients, utilizing digital health tools, enlisting specialist doctors, establishing networks, and facilitating professional counselling by nurses. CONCLUSIONS: This study is an attempt to evaluate an organizational change happened during COVID-19 pandemic. DOCs were created to support GPs and FPs as a link between primary healthcare and public health. Although several difficulties were disclosed, DOCs' experience can help to overcome the fragmentation of the systems and the duality between primary care and public health and make the system more resilient.

Repetitive Transcranial Magnetic Stimulation of the Human Motor Cortex Modulates Processing of Heat Pain Sensation as Assessed by the Offset Analgesia Paradigm.

Offset analgesia (OA), which is defined as a disproportionately large reduction in pain perception following a small decrease in a heat stimulus, quantifies temporal aspects of endogenous pain modulation. In this study on healthy subjects, we aimed to (i) determine the Heat Pain Threshold (HPT) and the response to constant and dynamic heat stimuli assessing sensitization, adaptation and OA phenomena at the thenar eminence; (ii) evaluate the effects of high-frequency repetitive Transcranial Magnetic Stimulation (rTMS) of the primary motor cortex (M1) on these measures. Twenty-four healthy subjects underwent quantitative sensory testing before and after active or sham 10 Hz rTMS (1200 stimuli) of the left M1, during separate sessions. We did not observe any rTMS-related changes in the HPT or visual analogue scale (VAS) values recorded during the constant trial. Of note, at baseline, we did not find OA at the thenar eminence. Only after active rTMS did we detect significantly reduced VAS values during dynamic heat stimuli, indicating a delayed and attenuated OA phenomenon. rTMS of the left M1 may activate remote brain areas that belong to the descending pain modulatory and reward systems involved in the OA phenomenon. Our findings provide insights into the mechanisms by which rTMS of M1 could exert its analgesic effects.

Electrophysiological evidence of subclinical trigeminal dysfunction in patients with COVID-19 and smell impairment: A pilot study.

Background: Smell and taste disturbances are among the most frequent neurological symptoms in patients with COVID-19. A concomitant impairment of the trigeminal nerve has been suggested in subjects with olfactory dysfunction, although it has not been confirmed with objective measurement techniques. In this study, we explored the trigeminal function and its correlations with clinical features in COVID-19 patients with impaired smell perception using electrophysiological testing. Methods: We enrolled 16 consecutive patients with mild COVID-19 and smell impairment and 14 healthy controls (HCs). Olfactory and gustatory symptoms were assessed with self-reported questionnaires. Electrophysiological evaluation of the masseter inhibitory reflex (MIR) and blink reflex (BR) was carried out to test the trigeminal function and its connections within the brainstem. Results: Masseter inhibitory reflex (MIR) analysis revealed higher latency of ipsilateral and contralateral early silent period in patients when compared with HCs. No significant differences between groups were detected as regards the duration of the early and late silent period. However, several patients showed a prolonged duration of the early silent period. BR evaluation disclosed only an increased amplitude of early components in patients. Conclusions: Patients with COVID-19 and smell impairment show a subclinical trigeminal nerve impairment. Trigeminal alterations mainly involve the oligosynaptic pathway, as a result of either direct viral damage or secondary neuroinflammation of the peripheral trigeminal fibers, whereas the polysynaptic ponto-medullary circuits seem to be spared. The prolonged duration of the early silent period and the increased amplitude of early BR response might reflect a compensatory upregulation of the trigeminal function as a consequence of the olfactory dysfunction.