On December 8, 1995, Jean-Dominique Bauby shaved, dressed, drank a cup of hot chocolate, and spent the day conducting business as the editor-in-chief of Elle magazine. By the end of that day, 43-year-old Bauby was in a coma, the result of a massive brain stem stroke.
One month later, Bauby had passed through several weeks of grogginess to become fully conscious--but was unable to speak or move. He had become a victim of locked-in syndrome (LIS). Once a powerful figure in the communications business, Bauby found himself unable to even signal for the attention of an attending nurse.
Chances are you've heard this story. But the reason you've heard it is because, in spite of it all, Bauby did find a way to communicate. Although it was a painstakingly slow process in which he would blink his left eyelid to choose letters from an alphabet board, Bauby spelled out his new life in the 132-page book The Diving Bell and the Butterfly, which was published shortly before his death in March 1997.1 Paradoxically, a method of communication--albeit rudimentary--was what persons in the medical community and around the world needed to appreciate the thoughts and feelings surging behind the silence and stillness of those who are locked in.
Physicians have learned from Bauby and other locked-in patients that the inability to communicate is far more frightening and debilitating than the inability to move. As a result, rehabilitation strategies for patients with LIS have focused on finding ways to facilitate communication using whatever means are available to a particular patient--whether blinking an eye, twitching a thumb, or even focusing one's thoughts to control a computer cursor with the help of a brain-computer interface (BCI). Clinicians believe that in the majority of cases, improved communication drastically improves patients' quality of life and allows them to be more actively involved with family and community. But some patients with LIS also have communicated feelings of frustration, depression, and even suicidality--thus sparking debate about what the quality of life for a locked-in patient really is and about the relative value of artificial ventilation and other expensive technologies used in sustaining their lives.
CLASSIFICATION
The incidence of LIS is difficult to determine from the medical literature, in large part because it is often misdiagnosed as coma, vegetative state, or minimally conscious state. Between 1997 and 2004, the French-based Association du Locked-In Syndrome (ALIS) registered 367 patients with LIS in its database,2 which has served as the basis for much of the research that has been done on this patient population. Some believe that the actual number of patients with LIS is much higher than that represented by the database.
"Probably every general neurologist has one of these cases in their practice," said Andrew J. Haig, MD, associate professor of physical medicine and rehabilitation at the University of Michigan. "It's not as uncommon as you'd think."
In 1979, Austrian researchers categorized LIS into 3 subtypes: classic LIS, in which conscious patients are immobile except for eye movement; incomplete LIS, in which minimal amounts of residual movement have been preserved in parts of the body beside the eyes; and total LIS, in which patients are conscious but unable to move any muscles at all.3
Although the Austrian terminology is used most often for classification of LIS, José Leon-Carrion, PhD, and colleagues at the University of Seville in 2002 suggested a different set of 3 subtypes: complete LIS, in which conscious patients may either be totally paralyzed or may have preserved eye movement as the result of a brain stem lesion; incomplete LIS, in which the patient may be able to perform other movements because of a partial recovery of the brain stem injury within a few weeks of LIS onset; and pseudo-LIS, in which the brain stem is secondarily affected by a primary cortical or cerebellar lesion.4
As Leon-Carrion's classification system suggests, the most frequent cause of LIS is thought to be injury to the basis pontis or ventral pontine region of the brain stem. In a review of cases published in 1986, James R. Patterson, MD, and Martin Grabois, MD, of Baylor College of Medicine found that injury to the area of the ventral pons was the cause of LIS in 82 of the 139 cases examined.5
The injury is most often vascular, a type cited in the literature as responsible for 52% to 100% of cases.2,5-9 In a recent analysis of 250 cases from the ALIS database, Steven Laureys, MD, PhD, a neurologist at the Cyclotron Research Centre and research associate for the Belgian Foundation for National Scientific Research in Liege, Belgium, found that 86% of patients had LIS of vascular origin.2 Brain stem lesions in LIS patients also may result from traumatic brain injury (TBI), which is cited as the cause in 9% to 31% of cases,5-9 or, infrequently, other causes ranging from brain tumor to prolonged hypoglycemia.2 Temporary LIS can be pharmacologically induced or stem from severe cases of peripheral polyneuropathy.10,11
Of note, a completely locked-in state also can occur in the end stages of amyotrophic lateral sclerosis (ALS),12 a situation that presents a very different set of patient care challenges than those associated with stroke or TBI. Because the degenerative progression of the disease can be predicted with some accuracy, ALS patients, their caregivers, and their physicians are able to prepare for the locked-in state and practice alternative means of communication before they are left with no other options. In this sense, they are spared some of the emotional trauma of stroke patients, for example, who may be in a locked-in state for weeks, months, or even years before a physician or (more often) a family member becomes aware that the patient is in fact fully conscious.9 However, ALS patients in a locked-in state have no hope of recovery; a patient who becomes locked in following a stroke or TBI is not likely to recover fully but at least can hope for small gains that could significantly improve quality of life.
