How often is the diagnosis of the permanent vegetative state incorrect? A review of the evidence

Abstract

Some research suggests that 40% of people in the vegetative state are misdiagnosed. This review investigates the frequency, nature and causes of reported misdiagnosis of patients in the vegetative state, focusing on the nature of the error. It is a systematic review of all relevant literature, using references from key papers identified. The data are summarized in tables. Five clinical studies of the rate of misdiagnosis in practice were identified, encompassing 236 patients in the vegetative state of whom 80 (34%) were reclassified as having some awareness, often minimal. The studies often included patients in the recovery phase after acute injury, and were poorly reported. Five systematic reviews of signs and technologically based neurophysiological tests were identified, and they showed that most studies were small, lacked accurate or important details, and were subject to bias. Studies were not replicated. Many signs and tests did not differ between people in the vegetative state and in the minimally conscious state, and those that did were unable to diagnose an individual patient. The few single case reports suggest that failure to ensure an accurate diagnosis of the underlying neurological damage and dysfunction could, rarely, lead to significant misdiagnosis usually in patients who had brain-stem damage with little thalamic or cortical damage. Significant misdiagnosis of awareness, with an apparently 'vegetative' patient having good awareness, is rare. Careful neurological assessment of the cause and routine measurement of awareness using the Coma Recovery Scale - Revised should further reduce mistakes.

Serum BDNF Levels Are Reduced in Patients with Disorders of Consciousness and Are Not Modified by Verticalization with Robot-Assisted Lower-Limb Training

“…In addition, no difference in the serum BDNF level between patients with UWS and those in an MCS was found. Both conditions are severe DOCs, and their clinical differentiation is often very difficult, leading to a high rate of misdiagnosis [46]. In this context, the difference in the BDNF level between patients with UWS and those in an MCS may be subtle, and the sample size in this study may have been inadequate to detect it.…”

The neurologic consultation: pointers and takeaways for intensivists

“…New guidelines suggest late (> 1-year) improvements primarily occurring in younger patients and ~ 20% of patients initially meeting criteria of a vegetative state [14]. Diagnostic error rates of 40% may be overstated due to insufficient neurologic skill and follow-up [15]. We do not know what to do here other than practice caution.…”

Predicting the outcome of a comatose patient at the bedside

“…Prolonged disorders of consciousness, such as a vegetative state or MCS, are, therefore, rarely seen after the first year of the injury. It is also a real possibility that patients were misdiagnosed and misclassified after being admitted to neurorehabilitation centres or nursing homes 1…”