**Abstract**

This is a prospective, hospital-based study reporting an update and the prevalence of nonconvulsive status epilepticus (NCSE) in patients with altered mental status (AMS) in Qatar. Patients presenting with NCSE are compared to controls. Two-hundred and fifty patients with AMS are involved. Patients with NCSE are: 65 (12–79 years, m, 37, f, 28); controls: 185 (12–80 years, m, 101, f, 84). Occurrence of NCSE in patients with AMS was 26%. NCSE patients were younger than controls (p < 0.001). Deaths in the NCSE group occurred in 31% and 19% in controls (p < 0.0007). Hospitalization length was longer in NCSE proper and in comatose NCSE compared to controls (p < 0.02, p < 0.03). Recovery occurred in 40% of NCSE patients and 53% of controls (p < 0.08). About 31% of patients (n = 21) had refractory NCSE and 9 died. This is the first study reporting the prevalence of NCSE in Qatar. This prevalence (26%) is in the middle range. NCSE did not do better than the controls, result being disappointing regarding comatose NCSE. NCSE is an emerging condition requiring rapid diagnosis and rapid treatment. Regarding the optimal duration of continuous EGG (cEEG) monitoring to diagnose the majority of NCSE cases, 3 days of cEEG monitoring could accomplish this task.

**Keywords:** nonconvulsive seizures, nonconvulsive status epilepticus, epidemiology, treatment, antiseizure medications, outcome
