Background Cranial nerve involvement is not commonly encountered in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP); this is especially true for involvement of the hypoglossal nerve. Neither Beevor's sign nor its inverted form has previously been described in CIDP. Case presentation A 28-year-old man presented with distal-predominant limb weakness and numbness at the age of 18. A diagnosis of CIDP was made, which was confirmed by electrodiagnostic evidence of demyelination. He responded well to intravenous immunoglobulin and glucocorticoid treatment and achieved remission for 5 years. However, the same symptoms relapsed at the age of 28 and lasted for 10 months. On examination, in addition to limb sensory impairment and muscle weakness, mild bilateral facial paresis, tongue atrophy and fasciculations, and inverted Beevor's sign were also observed. A brief literature review of cranial nerve involvements in CIDP and Beevor's sign or its inverted form were also performed. Conclusions Cranial nerves may be affected in patients with CIDP. Facial palsy is most frequently present, while hypoglossal nerve involvement is rare. Inverted Beevor's sign can appear in CIDP patients.

Background and PurposeThe diagnosis of multiple system atrophy (MSA) remains challenging in clinical practice. This study investigated the value of hypointense signals in the putamen (“black straight-line sign”) in diffusion-weighted imaging (DWI) of brain MRI for distinguishing (MSA) from Parkinson's disease (PD).MethodsWe retrospectively enrolled 30 MSA patients, 30 PD patients, and 30 healthy controls who had undergone brain MRI between 2016 and 2020. Two readers independently assessed the signal intensity of the bilateral putamen on DWI. The putaminal hypointensity was scored using 4-point visual scales. Putaminal hypointensity and the presence of a “black straight-line sign” were statistically compared between MSA and PD or healthy controls.ResultsThe mean scores of putaminal hypointensity in DWI in the MSA group were significantly higher than in both the PD (U = 315.5, P = 0.034) and healthy control groups (U = 304.0, P = 0.022). Uni- or bilateral putaminal hypointensity in DWI with a score ≥2 was identified in 53.3% (16/30), 16.7% (5/30), and 13.3% (4/30) of MSA, PD, and healthy controls, respectively, with significant differences between MSA and PD (X2 = 8.864, P = 0.003) or healthy controls (X2 = 10.800, P = 0.001). Notably, the “black straight-line sign” of the putamen was observed in 16/30 (sensitivity 53.3%) patients with MSA, while it was absent in PD and healthy controls (specificity 100%). There were no significant differences for the presence of “black straight-line sign” in the MSA-P and MSA-C groups (X2 = 0.433, P = 0.510).ConclusionThe “black straight-line sign” of the putamen in DWI of head MRIs has the potential to serve as a diagnostic marker for distinguishing MSA from PD.