The locked-in syndrome : what is it like to be conscious but paralyzed and voiceless?
Section snippets
Classical, incomplete and total locked-in syndrome
Plum and Posner (1983) described the LIS as
“a state in which selective supranuclear motor de-efferentation produces paralysis of all four limbs and the last cranial nerves without interfering with consciousness. The voluntary motor paralysis prevents the subjects from communicating by word or body movement. Usually, but not always, the anatomy of the responsible lesion in the brainstem is such that locked-in patients are left with the capacity to use vertical eye movements and blinking to
Etiology
LIS is most frequently caused by a bilateral ventral pontine lesion (e.g., Plum and Posner, 1983, Patterson and Grabois, 1986) (Fig. 2A). In rarer instances, it can be the result of a mesencephalic lesion (e.g., Chia, 1991; Meienberg et al., 1979, Bauer et al., 1979). The most common etiology of LIS is vascular pathology, either a basilar artery occlusion or a pontine hemorrhage (see Table 1). Another relatively frequent cause is traumatic brain injury (Britt et al., 1977; Landrieu et al., 1984
Misdiagnosis
Unless the physician is familiar with the signs and symptoms of the LIS, the diagnosis may be missed and the patient may erroneously be considered as being in a coma, vegetative state, or akinetic mustism (Gallo and Fontanarosa, 1989). In a recent survey of 44 LIS patients belonging to ALIS, the first person to realize the patient was conscious and could communicate via eye movements most often was a family member (55% of cases) and not the treating physician (23% of cases) (Table 2) (
Survival and mortality
It has been stated that long-term survival in LIS is rare (Ohry, 1990). Mortality is indeed high in acute LIS (76% for vascular cases and 41% for nonvascular cases) with 87% of the deaths occurring in the first 4 months (Patterson and Grabois, 1986). In 1987, Haig et al. (1987) first reported on the life expectancy of persons with a LIS, showing that individuals can actually survive for significant periods of time. Encompassing 29 patients from a major US rehabilitation hospital who had been in
Prognosis and outcome
Classically, the motor recovery of LIS of vascular origin is very limited (Patterson and Grabois, 1986, Doble et al., 2003), even if rare cases of good recovery have been reported (McCusker et al., 1982; Ebinger et al., 1985). Chang and Morariu (1979) reported the first transient LIS caused by a traumatic damage of the brain stem. In their milestone paper, Patterson and Grabois (1986), reviewed 139 patients — 6 cases from the authors’ rehabilitation center in Texas, USA, and 133 from 71
Communication
In order to functionally communicate, it is necessary for the LIS patient to be motivated and to be able to receive (verbally or visually, i.e., written commands) and emit information. The first contact to be made with these patients is through a code using eyelid blinks or vertical eye movements. In cases of bilateral ptosis, the eyelids need to be manually opened in order to verify voluntary eye movements on command. To establish a yes/no eye code, the following instruction can suffice :
Neuropsychological testing
Surprisingly, there are no systematic neuropsychological studies of the cognitive functions in patients living with LIS. Most case reports, however, failed to show any significant cognitive impairment when LIS patients were tested 1 year or more after the brainstem insult. Allain et al. (1998) performed extensive neuropsychological testing in two LIS patients studied 2 and 3 years after their basilar artery thrombosis. Patients communicated via a communication print–writer system and showed no
Quality of life
In March 2002, at the annual meeting of ALIS at La Pitié-Salpétrière hospital in Paris, patients with LIS and their family members were asked to fill in the Short Form-36 (SF-36) questionnaire (Ware et al., 1993) on quality of life. Seventeen chronic (i.e., >1 year) locked-in patients who did not show major motor recovery (i.e., used eye movements or blinking as the major mode of communication) and who lived at home replied to the questionnaire (mean age 44±6 years; range 33–57 years). Mean
The right to die or the right to live ?
The American Academy of Neurology (AAN) has published a position statement concerning the management of conscious and legally competent patients with profound and permanent paralysis (Ethics and Humanities Subcommittee of the AAN, 1993, Bernat et al., 1993, Allen, 1993). The conclusion is that such patients have the right to make health care decisions about themselves, including whether to accept or refuse life-sustaining therapy — either not start or stop once it started. Doctors caring for
Conclusion
The discussed data stress the need for heath care workers who might be confronted to the LIS to recognize this infrequent syndrome as early as possible and to adapt their bedside-behavior. Physicians who take care of acute LIS patients need a better understanding of their long-term outcome. With appropriate medical care, most patients can return home and their life expectancy is several decades. Opposite to the beliefs of many healthy individuals, LIS patients self-report a meaningful quality
Acknowledgments
This research was supported by the French Association Locked in Syndrome (ALIS), the Belgian Fonds National de la Recherche Scientifique (FNRS), the Centre Hospitalier Universitaire Sart Tilman, Liège, the University of Liège, the Erasme Hospital, University of Brussels, Belgium, and the Mind Science Foundation, San Antonio, Texas, USA. Steven Laureys is Research Associate at FNRS. The authors thank all participating LIS patients, their families, and their physicians and acknowledge Véronique
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