Figure 1 Antineuronal antigen reactivity of sera, expressed as optical density (OD) and SD: motor neuron disease (n = 145), normal pressure hydrocephalus (n = 23), healthy subjects (n = 22) and definite paraneoplastic neurological syndromes (PNS), according to established criteria7 (n = 21). Diagnostic cut‐off values: antiamphiphysin 0.099, CV2/CRMP5 0.156, HuD 0.077, Ma2 0.177, Ri 0.065 and Yo 0.049.