In mid-May, my 94-year-old father and I were discussing the significance of 0 and its impact on theoretical mathematics. Four weeks later, he was totally demented. He was taking no medication, and all routine blood and urine studies, brain imaging, and a spinal tap yielded no diagnosis. One week later, a high titer of Lyme antibody was found in a cerebrospinal fluid specimen, and the diagnosis of neuroborreliosis was unequivocally substantiated by Western blot analysis. Eight weeks after a 28-day course of intravenous ceftriaxone sodium (1 g/d), his mental function returned to an estimated 90% of his premorbid intellect. That was when I gave him a short vignette written in a humorous vein, relating to the purchase of a ballpoint pen.
Ramanan SV. Loss of the Sense of Humor. Arch Intern Med. 2000;160(16):2546. doi: