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Liverpool Seizure Severity Scale 2.0 (LSSS 2.0)
Availability
All copyrights for the scale are in the public domain. The LSSS 2.0 can be used as printed and replicated and used without modification by anyone without express permission of the developers (Scott-Lennox et al., 2001).
Classification
Supplemental: Epilepsy
Short Description of Instrument
Background: The original Liverpool Seizure Severity Scale was developed with 16 items that measured two domains: perception of control over seizures and ictal/post-ictal effects (Baker et al., 1991). Although psychometric properties were relatively strong, subsequent experience with the scale indicated that further development was needed. In the first revised version of the original scale, items were increased to 20 and response choices were increased for selected items.  Although the revised version had some good psychometric properties, there were issues with the domain measuring perception of seizure control. The internal consistency reliabilities were not consistently strong, and an expert panel found the perception of seizure control subscale to measure impact on life and not seizure severity. In addition, there were issues related to handling missing data and handling patients with more than one seizure type. When adjustments were made to accommodate patients with multiple seizure types, the result was a more cumbersome scale that was less user friendly for patient self-report (Baker, Smith, Jacoby, Hayes, & Chadwick, 1998). Therefore, the developers substantially revised the questionnaire and created a revised scoring system. This latter revised scale, which was labeled the Liverpool Seizure Severity Scale 2.0 (LSSS 2.0) (Scott-Lennox, Bryant-Comstock, Lennox, & Baker, 2001), is the version that is recommended for inclusion in the common data elements repository.
 
Description: The Liverpool Seizure Severity Scale (LSSS) and the Seizure Severity Questionnaire (SSQ) are recommended for the measurement of perception of seizure severity in adults with epilepsy.The LSSS 2.0 version has 12 items and one dimension that includes items related to ictal/post-ictal effects. Patients are asked to complete the questionnaire with the most severe seizure that they have experienced in the past 4 weeks in mind. Before completing the 12 items, patients are asked to list how many seizures they have experienced during the past 4 weeks. If they have not had any seizures in the past 4 weeks, they do not complete the rest of the questionnaire. If they have had at least one seizure, they complete the 12 items. Of these, the first item asks the patient to rate the severity of his/her seizures on a 0 to 3 scale of "very severe to very mild."  The remaining 11 items are statements about the nature of their seizures (3 items) or statements about the after effects of their seizures (8 items). Of these 11 items, patients are asked to respond to 8 items using a 0 to 3 response scale, to 2 items using a 0 to 4 response scale, and to 1 item using a 0 to 5 response scale.
 
Psychometric Properties: A factor analysis showed a single factor or dimension and supported the validity of the scale. The scale was also found to have adequate internal consistency reliability with a Cronbach's alpha of >0.7 (Scott-Lennox et al., 2001). A known-groups validity analysis provided clinical evidence for validity (Scott-Lennox et al., 2001).  Another study demonstrated that seizure severity was significantly related to quality of life, with individuals with lower (worse) seizure severity scores having worse quality of life scores. In this study, the association between seizure frequency and LSSS 2.0 total score was not statistically significant (Bautista & Glen, 2009).
Scoring
The total score ranges from 0 (no seizures) to 100 (most severe possible). There are two steps to scoring:  
    • Step 1: Patients who have not had a seizure in the past 4 weeks are given a "0." If the number of seizures during the past 4 weeks is greater than 0, then proceed to Step 2.
    • Step 2: Reverse code responses to 9 items so that a lower value reflects less seizure severity. If responses to 4 or more questions are missing, assign a missing score for the scale. If responses to 1 to 3 questions are missing, replace the missing responses with the mean of the non-missing items.  Sum the responses to questions 1 to 12, divide by 40, and multiply by 100.

Rationale/Justification
Weaknesses: The scale is not valid for people who were seizure free in the prior 4 weeks (Bautista & Glen, 2009). There are also concerns about the validity of the scale for people with episodic seizures, which is especially a concern when a treatment is being evaluated over time. For example, if a patient becomes seizure free after treatment, it could reflect response to treatment or a pattern of severe but infrequent seizures (Scott-Lennox et al., 2001).  Another concern with only describing the most severe seizure is that frequent minor seizures might be overlooked.
References
The entire scale is provided in Appendix A and the scoring instructions are provided in Appendix B in the first reference below:
 
Scott-Lennox J, Bryant-Comstock L, Lennox R, Baker GA. Reliability, validity and responsiveness of a revised scoring system for the Liverpool Seizure Severity Scale. Epilepsy Res. 2001;44(1):53-63.
 
Baker GA, Smith DF, Dewey M, Morrow J, Crawford  PM, Chadwick DW. The development of a seizure severity scale as an outcome measure in epilepsy. Epilepsy Res. 1991;8(3):245-251.
 
Baker GA, Smith DF, Jacoby A, Hayes JA., Chadwick DW. Liverpool Seizure Severity Scale revisited. Seizure. 1998;7(3):201-205.
 
Bautista RE, Glen ET. Seizure severity is associated with quality of life independent of seizure frequency. Epilepsy Behav. 2009;16(2):325-329. doi:10.1016/j.yebeh.2009.07.037