Classical crossed brain stem syndromes: myth or reality?

Numerous crossed brain stem syndromes have been described, especially in the nineteenth century. While these syndromes are passed on in neurological textbooks, their relevance in clinical neurology remains to be elucidated. To investigate the prevalence of classical crossed brain stem syndromes in clinical practice, we prospectively recruited 308 consecutive patients with signs and symptoms indicative of acute brain stem infarction. Standardized high-resolution MR imaging and multimodal electrophysiological brain stem testing were applied to localize the site of the acute lesion. We performed a computer-based correlation of clinical signs and symptoms of our patients to those reported in the original historical publications for more than 25 crossed brain stem syndromes. Fourteen cases matched the clinical criteria of Wallenberg's syndrome, two patients had Babinski-Nageotte's syndrome, two had Raymond-Cestan's, one showed Weber's, and one Claude's syndrome. All other tested syndromes were not present in the cohort. More than 20% of patients showed different, so far unnamed crossed symptom combinations. In conclusion, except for Wallenberg's syndrome, classical crossed brain stem syndromes do not seem to play a relevant role in clinical neurology. Other syndromes may serve as theoretical models only that illustrate possible neuroanatomical connections in the human brain stem. This is complicated, however, by considerable topographic and terminological inconsistencies.