Selective atrophy of the brachialis muscle in neuralgic amyotrophy: ultrasound imaging of fascicular nerve damage

[no abstract available

Utility of preoperative electrodiagnosis together with peripheral nerve high-resolution ultrasound: a complex case report of Neurofibromatosis type I

Our case report underscores the importance of electroneuromyography (ENMG) combined with peripheral nerve high-resolution ultrasound (HRUS) in the evaluation of neurofibromatosis type 1 (NF1). A 49-year-old woman affected by NF1 came to our attention because of new-onset left arm weakness and atrophy. Debulking of a cervicothoracic C7-T1 neurofibroma had been performed 8 years earlier. On current admission, magnetic resonance imaging disclosed increased lesion volume that was thought to cause the neurologic deficits by compressing the C8 root. Findings from intraoperative neurophysiologic monitoring during repeat debulking suggested that C8 root integrity had been compromised during the first operation and that the new-onset symptoms probably stemmed from peripheral nervous system damage distal to the cervical roots. Postoperative ENMG showed chronic denervation signs in the muscles innervated by C7-C8-T1 roots, moderate carpal tunnel syndrome (CTS), and ulnar nerve conduction block at the elbow. HRUS confirmed the CTS and revealed multiple neurofibromas involving the distal tract of the radial, ulnar, and median nerves. Surgical debulking was considered unnecessary in this case. ENMG combined with nerve and plexus HRUS evaluation may help identify the cause of neurologic deficits and choose the best surgical option in such complex clinical conditions as NF1

Very early and early neurophysiological abnormalities in Guillain-Barr\ue9 Syndrome: a 4-year retrospective study

In its initial stages, Guillain Barr\ue9 syndrome (GBS) is difficult to identify because diagnostic criteria may not always be fulfilled. With this retrospective study, we wanted to identify the most common electrophysiological abnormalities seen on neurophysiological examination of GBS patients and its variants in the early phases

Defects and magnetic hyperfine fields in ZrFe/sub 2/ investigated using perturbed-angular-correlation spectroscopy

We have measured the temperature dependence of the electric and magnetic hyperfine interactions at 181Ta nuclei substituted into the Zr site in the Laves-phase compound ZrFe2, using the perturbed angular correlation of g rays emitted after the b2 decays of 181Hf probe nuclei. Although the overall crystal structure is cubic, a weak strongly damped electric-quadrupole interaction is observed, which shows no significant temperature dependence over the investigated temperature range from 290–1300 K. Thus below the magnetic ordering temperature TC of 631~2! K we observe combined magnetic-dipole and electric-quadrupole hyperfine interactions. Two separate magnetic components characterize the magnetic-dipole interactions. For the interaction at the primary site, which is occupied by 70–80% of the probes, the Larmor frequency measured at temperature has a value of vL5407(1) Mrad sec21. The secondary site is populated by the remaining 20–30% of the probes, for which the corresponding Larmor frequency has a room temperature value of vL 5579(3) Mrad sec21. We attribute the primary interaction to the ‘‘perfect-crystal’’ probe environment at the Zr site, whereas we ascribe the secondary interaction to the enhancement of the transferred hyperfine field by the presence of Fe antisite defects near the Zr site. At temperatures below but very close to TC , those frequencies cannot be determined for either interaction, because the magnetic-hyperfine and the electricquadrupole frequencies converge to comparable values

Defects and magnetic hyperfine fields in ZrFe/sub 2/ investigated using perturbed-angular-correlation spectroscopy

We have measured the temperature dependence of the electric and magnetic hyperfine interactions at 181Ta nuclei substituted into the Zr site in the Laves-phase compound ZrFe2, using the perturbed angular correlation of g rays emitted after the b2 decays of 181Hf probe nuclei. Although the overall crystal structure is cubic, a weak strongly damped electric-quadrupole interaction is observed, which shows no significant temperature dependence over the investigated temperature range from 290–1300 K. Thus below the magnetic ordering temperature TC of 631~2! K we observe combined magnetic-dipole and electric-quadrupole hyperfine interactions. Two separate magnetic components characterize the magnetic-dipole interactions. For the interaction at the primary site, which is occupied by 70–80% of the probes, the Larmor frequency measured at temperature has a value of vL5407(1) Mrad sec21. The secondary site is populated by the remaining 20–30% of the probes, for which the corresponding Larmor frequency has a room temperature value of vL 5579(3) Mrad sec21. We attribute the primary interaction to the ‘‘perfect-crystal’’ probe environment at the Zr site, whereas we ascribe the secondary interaction to the enhancement of the transferred hyperfine field by the presence of Fe antisite defects near the Zr site. At temperatures below but very close to TC , those frequencies cannot be determined for either interaction, because the magnetic-hyperfine and the electricquadrupole frequencies converge to comparable values

Guillain-Barr\ue9 syndrome and COVID-19: an observational multicentre study from two Italian hotspot regions

Objective: Single cases and small series of Guillain-Barr\ue9 syndrome (GBS) have been reported during the SARS-CoV-2 outbreak worldwide. We evaluated incidence and clinical features of GBS in a cohort of patients from two regions of northern Italy with the highest number of patients with COVID-19. Methods: GBS cases diagnosed in 12 referral hospitals from Lombardy and Veneto in March and April 2020 were retrospectively collected. As a control population, GBS diagnosed in March and April 2019 in the same hospitals were considered. Results: Incidence of GBS in March and April 2020 was 0.202/100 000/month (estimated rate 2.43/100 000/year) vs 0.077/100 000/month (estimated rate 0.93/100 000/year) in the same months of 2019 with a 2.6-fold increase. Estimated incidence of GBS in COVID-19-positive patients was 47.9/100 000 and in the COVID-19-positive hospitalised patients was 236/100 000. COVID-19-positive patients with GBS, when compared with COVID-19-negative subjects, showed lower MRC sum score (26.3\ub118.3 vs 41.4\ub114.8, p=0.006), higher frequency of demyelinating subtype (76.6% vs 35.3%, p=0.011), more frequent low blood pressure (50% vs 11.8%, p=0.017) and higher rate of admission to intensive care unit (66.6% vs 17.6%, p=0.002). Conclusions: This study shows an increased incidence of GBS during the COVID-19 outbreak in northern Italy, supporting a pathogenic link. COVID-19-associated GBS is predominantly demyelinating and seems to be more severe than non-COVID-19 GBS, although it is likely that in some patients the systemic impairment due to COVID-19 might have contributed to the severity of the whole clinical picture