In a letter to the editor published Thursday in the New England Journal of Medicine, physicians from around the world shed light on a disturbing phenomenon: Their review of YouTube videos depicting movement disorders, such as Parkinson’s disease, found that in many instances those videos are inaccurate and misleading.

Acting on tips from patients, the doctors undertook an analysis of the most-viewed YouTube videos related to each of seven kinds of movement disorder, including Parkinson’s, tics, tremors, dystonia, chorea and myoclonus. Though the letter acknowledges that a physician can’t make a full diagnosis without examining a patient and taking his history, the neurologists rating the videos were able to distinguish people whose movement disorders were organic — i.e. rooted in physical pathology — versus psychogenic, or related to psychological factors.

Of 29 videos featuring people with movement disorders, the review found 66 percent of the subjects’ disorders were psychogenic and just 34 percent organic.

Moreover, 53 percent of the videos deemed to show psychogenic movement disorder recommended specific treatments for that disorder, while just 20 percent of the organic movement disorder videos offered treatment advice.

One video described as showing facial dystonia showed different patterns of facial spasm that appeared to be triggered by an electrical stimulator, and it suggested that dystonia could be alleviated if the patient wore cotton clothes and avoided radiation. Other recommendations were potentially more serious, proposing the use of immunosuppressive agents or invasive or expensive diagnostic tests, and some videos claimed that profound benefit could be had from interventions such as craniosacral massage and herbal remedies prescribed by health care providers.

The fact that such a large number of videos showing psychogenic movement disorders are available on the Internet highlights an underlying problem that affects virtually every medical specialty, and the information these videos provide can interfere with the effective recognition and care of patients with a movement disorder.