The National Hospital Seizure Severity Scale: A Further Development of the Chalfont Seizure Severity Scale

Abstract

Seizure severity scales have recently been identified as an important additional outcome measure in trials of new antiepileptic drugs (AEDs). The National Hospital Seizure Severity Scale (NHS3) is presented as a refined version of the Chalfont Seizure Severity Scale. The principal advantages of the new version are that it is quicker and simpler to apply, the limits of reliability are now clearly defined, and construct validity for the scale is available. The scale is administered by a health professional during an interview with a patient and a witness to the seizures. It contains seven seizure-related factors and generates a score from 1 to 27. An intraclass correlation coefficient of 0.90 was obtained during interobserver and test-retest reliability assessment, suggesting that the scale is sufficiently reliable for group studies. Scores for an individual patient should be interpreted with caution in light of the limits of agreement obtained. Validation experiments indicate that NHS3 measures seizure severity in a manner compatible with the subjective impression of people with epilepsy. We suggest that the NHS3 is a valid, easily applicable measure of seizure severity that is acceptably reliable for use in trials of novel AEDs.

The interrelationship between clinical and immunity variables in epilepsy

“…An assessment of seizures severity was undertaken according to the National Hospital Seizure Severity Scale (NHS3) (O'Donoghue et al, 1996).…”

“…Clinical and experimental data suggest that both innate and adaptive (acquired) immunity may be involved in epilepsy pathogenesis (Orozco-Suarez et al, 2012). Innate immune mechanisms represent an immediate and nonspecific host response against pathogens via activation of resident cerebral immune cells and inflammatory mediators.…”

Beneficial effects on sleep of vagus nerve stimulation in children with therapy resistant epilepsy

“…The severity of the seizures was scored with the National Hospital Seizure Severity Scale (NHS3), a further development of the Chalfont Seizure Severity Scale described by O'Donoghue et al 22 QOL was assessed by a visual analogue scale and parents' perception of the children's general behaviour problems were quantified by using the total score of the Child Behaviour Checklist (CBCL). Follow-up assessments were performed at three and nine months after VNS initiation (Table 2B).…”

A Twin Study of Genetic Influences on Epilepsy Outcome

“…Whilst assessment in terms of Seizure Status provides an unequivocal measure of outcome, it may fail to make the fine distinctions between the various clinical outcomes of epilepsy necessary to show an etiology-independent genetic effect on outcome. A number of seizure severity scales have been described, but these are scales of seizure burden (seizure frequency and their clinical impact) for use in drug trials and are not measures of long-term outcome (Baker et al, 1991;Cramer, 2001;Cramer et al, 1983;O'Donoghue et al, 1996). In an attempt to better discriminate between the various epilepsy outcomes, we constructed an Outcome Scale that combined items on Seizure Status with treatment decisions.…”