When the diagnosis is in the patient's hand and in the neurologist's eye.

The objective of this study was to encompass current knowledge about pathophysiological mechanisms of those specific hand postures or deformities caused by central nervous system disorders. In the era of high-resolution neuroimaging and molecular biology, clinicians are progressively losing confidence with neurological examination. Careful hand observation is of key importance in order to differentiate neurological from non-neurological conditions, central from peripheral aetiologies, and organic from functional disorders. Localizing the potential anatomical site is essential to properly conduct subsequent exams. We provided a practical guide for clinicians to recognize hand patterns caused by central nervous system disorders, avoiding mimicking conditions, thus optimizing and prompting the diagnostic pathway.

Progressive motor neuron syndromes with single CNS lesions and CSF oligoclonal bands: never forget solitary sclerosis!

We describe 3 cases of solitary sclerosis (SS), a rare condition characterized by a single inflammatory demyelinating lesion in the white matter of the brain or spinal cord. All patients had progressive limb motor impairment (patient 1, 66-year-old female: left spastic hemiparesis; patient 2, 39-year-old male: right spastic hemiparesis; patient 3, 42-year-old female: proximally predominant left upper limb weakness with amyotrophy and fasciculations). In all patients, MRI disclosed a single small T2-hyperintense demyelinating lesion: in the right anterior paramedian upper medulla, in the median-left paramedian anterior lower medulla, and in the left paramedian anterior cervical spinal cord at C4 level, respectively. In patients 1 and 2, transcranial magnetic stimulation (TMS) demonstrated altered motor evoked potentials (MEPs) and increased central motor conduction time (CMCT) in the affected limbs; in patient 3, needle EMG revealed chronic neurogenic changes in C5-C7 muscles of left upper limb. Patients 1 and 2 had normal brain 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET). CSF analysis demonstrated IgG oligoclonal bands in all patients. In patients 2 and 3, levels of neurofilament light chain (NFL) in CSF and serum, respectively, were within normal limits. The three cases were consistent with the diagnosis of SS. Notably, while the first two cases mimicked Mills' syndrome (the hemiparetic variant of primary lateral sclerosis, PLS), the third one was rather reminiscent of amyotrophic lateral sclerosis (ALS). This suggests including SS in the differential diagnosis not only of PLS, but also of ALS. We also report the first quantification of NFL levels in SS.