Adult patients presenting with slowly progressive hand weakness and wasting (HWW) without signs of upper motor neuron involvement and unconvincing cervical MRI signs of disk protrusion are a diagnostic challenge. Clinical and electrophysiological follow-up is needed to reach the most probable diagnosis.We describe 4 adult patients who presented with HWW and involuntary tremor-like movements of the thumb.We performed electrodiagnostic testing (EDX) two times, between 3 and 6months and 12 and 24months, after onset of symptoms. Cranial and cervical magnetic ressonance and laboratory workout were performed in all patients.Hyposthesia in the ulnar territory was the most common complaint that did not change between consultations. Muscle strength was decreased in fingers abduction-adduction movements. Thumb tremor was present and correlated with fasciculations in thenar and interossei muscles. The compound muscle and sensory nerve action potentials were reduced in median and ulnar nerves. We observed denervation signs in thenar and hypothenar muscles but not in biceps. The EDX signs did not change in the second examination.Fasciculations in wasted hand muscles may induce involuntary movements mimicking tremor. Stabilization of symptoms and neurophysiological data favor spinal cord focal lesions over motor neuron disease.