• disability
• multiple sclerosis
• Expanded Disability Status Scale
• Guy’s Neurological Disability Scale

• MS, multiple sclerosis
• EDSS, Expanded Disability Status Scale
• GNDS, Guy’s Neurological Disability Scale

The most common neurological outcome measure for multiple sclerosis (MS) patients is the Expanded Disability Status Scale (EDSS). Originally, Kurtzke developed this disability status scale,¹ later revised to a more refined classification system, known as the EDSS.² The EDSS is based on a neurological examination of eight functional systems usually performed by a medical doctor. While problems of standardisation, resulting in suboptimal interrater reliability, marginal sensitivity to change and bias to locomotor function have been described^3–6 the EDSS remains a useful tool for classifying disability in MS patients.

In a longstanding invalidating neurological disease like MS where cure is not yet possible, disability as perceived by the patient is an important measure and for this purpose the Guy’s Neurological Disability Scale (GNDS)⁷ was recently developed. The GNDS measures disability based on patient self report, embraces the whole range of disabilities that can be encountered in the course of MS, is patient orientated, user friendly, and not biased to any particular disability.^7,8 The GNDS is a questionnaire, divided in 12 subcategories, directed to assess a patient’s disability in the previous month by patient interview and can be applied by any healthcare worker. It is therefore extremely practical and capable of incorporating patients’ views of their disability in a structured manner.^8,9

In a previous study we showed good cross sectional correlations between EDSS and GNDS: these correlations were mainly attributable to the importance of spinal cord related neurological functions for both scales.⁹ That study also confirmed that the GNDS measures other dimensions of disability than the EDSS and incorporates patients’ perspectives, both of which can cause marked discrepancies between scores on the two scales. Such discrepancies between objective measurements and subjective complaints have been demonstrated in many studies. To give just one …