Neurology · 5 authors, 1 centre
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This nationwide cross-sectional study found a low prevalence of institutionalized patients in the minimally conscious state (MCS) in the Netherlands, estimated at 0.2–0.3 per 100,000 inhabitants. Most patients were male (68.8%), with traumatic brain injury as the leading cause (65.6%), and just over half received specialized prolonged disorder of consciousness (pDoC) rehabilitation. These findings provide essential epidemiological data to guide the organization of pDoC care.
**Background:** The minimally conscious state (MCS) is a severe prolonged disorder of consciousness (pDoC) following acquired brain injury, characterized by inconsistent but observable signs of consciousness. Despite its clinical importance—affecting pain management, prognosis, rehabilitation potential, and ethical decisions—epidemiological data on MCS are scarce. Previous studies in France (2009) and Austria (2011) reported MCS prevalences of 1.9 and 1.5 per 100,000 citizens, respectively, but lacked on-site verification of consciousness. The Netherlands, with its well-organized healthcare system and nationwide pDoC care network, offers an ideal setting for a rigorous prevalence study using the gold-standard Coma Recovery Scale-Revised (CRS-R).
**Methods:** This descriptive cross-sectional study was conducted on the point prevalence date of September 15, 2021. All 86 Dutch hospitals, all 5 specialized pDoC rehabilitation facilities, and all 274 nursing homes were contacted to identify patients with pDoC (≥28 days after brain injury, age ≥16 years, excluding neurodegenerative or malignant causes). Legal representatives provided written informed consent. Level of consciousness (LoC) was verified on-site by an experienced physician using a single CRS-R assessment, supplemented by serial CRS-R assessments if available (≥5 assessments). Patients were classified as unresponsive wakefulness syndrome/vegetative state (UWS/VS), MCS (subcategorized as MCS− or MCS+), or exit-MCS. Prevalence was calculated per 100,000 Dutch inhabitants using actual census data (approximately 18 million).
**Key Results:** Treating physicians reported 70 patients with pDoC; 64 met inclusion criteria. Consent was obtained for 49 patients, and LoC was verified in 49 (15 unverified due to lack of consent, recovery, deterioration, or death). Of the verified patients, 38 (78%) had a pDoC: 6 (16%) in UWS/VS and 32 (84%) in MCS (14 MCS−, 18 MCS+). Eleven patients (22%) were in exit-MCS. The prevalence of institutionalized MCS patients was 0.2–0.3 per 100,000 inhabitants (32 verified plus 15 unverified possible MCS cases). Mean age was 44.8 years (SD 15.9, range 19–74); 68.8% were male. Traumatic brain injury accounted for 65.6% (21/32), mainly road-traffic accidents and falls; nontraumatic causes (34.4%) included postanoxic encephalopathy and subarachnoid hemorrhage. Median time since injury was 16.5 months (IQR 5.25–52.5, range 1 month–17 years). Seventeen patients (53.1%) were in specialized pDoC rehabilitation (9 early intensive neurorehabilitation, 8 prolonged intensive neurorehabilitation), and 14 (43.8%) were in nursing homes. On the single CRS-R assessment, the most frequent signs of consciousness were visual pursuit (46.9%), reproducible movement to command (40.6%), and automatic motor response (31.3%). Additional structured observations included context-related emotions (21.9%). In 8 patients (25%), the single CRS-R assessment indicated UWS/VS, but serial assessments or structured observations confirmed MCS; low arousal was present in all 8. Interfering factors (e.g., low arousal, sedative medication) were observed in 25 of 32 MCS patients.
**Clinical Implications:** This study provides the first nationwide, CRS-R–verified prevalence of MCS, revealing a rate 7–10 times lower than previous European estimates. The low prevalence may reflect differences in end-of-life decision-making (e.g., earlier withdrawal of life-sustaining treatment in the Netherlands), improved diagnostic accuracy through serial assessments, and a possible shift from UWS/VS to MCS due to better rehabilitation access. The findings underscore the necessity of serial CRS-R assessments to avoid misdiagnosis, as 25% of MCS patients showed no signs of consciousness on a single assessment. The data are already being used to organize pDoC care in the Netherlands, including the development of a central patient registry and outcome studies. Limitations include restriction to institutionalized patients (excluding home care or other facilities) and potential underestimation due to interfering factors or reliance on single assessments in some cases. International comparative research is recommended to explore cross-national variations in pDoC prevalence.