A neuromuscular disease characterized by sporadic bouts of ataxia with or without continuous muscle movement. The disease is Experimental Factor Ontology entry EFO_1000638 (Isaacs syndrome). Also known as: Acquired Neuromyotonia, Continuous Muscle Activity Syndrome, Isaacs' syndrome, Isaacs-Mertens syndrome, NMT, Neuromyotonia, Pseudomyotonia Syndrome of Isaacs, episodic ataxia.