Nottingham method of Stereognosis assessment: a study to assess inter-rater reliability

REFERENCE: Gaubert CS, Mockett SP Inter-rater reliability of the Nottingham method of stereognosis assessment Clinical Rehabilitation 2000; 14 153 - 159

SUMMARY

Objective: To investigate the ability of different observers to classify stroke patients using the Nottingham Sensory Assessment

Design: Method comparison study

Setting: Stroke Unit, Nottingham City Hospital NHS Trust.

Patients: A total of 20 stroke patients aged between 40 and 93 years agreed to participate. Patients were excluded from the study if they presented with a0 any residual upper limb deficit from a previous stroke, b) a score of less than 20/ 30 on the Mini Mental State Examination and c) any evidence of body neglect as assessed by the stroke unit physiotherapists.

Main outcome measures: Agreement of scores

Main results: Of the 20 patients who agreed to participate, there were 11 men and 9 women, with a mean age of 70.21 years (+13.5). 9 patients presented with right-sided hemiparesis and 7 presented with left-sided hemiparesis, 4 patients were affected bilaterally. Mean time since stroke was 3.85 weeks ( + 2.78). Examiners 1 and 2 assessed 7 patients and examiners 1 and 3 assessed 13. The ability of the examiners to assess and classify using the stereognosis assessment tool was analysed using the kappa coefficient of agreement. There was found to be good levels of agreement between the examiners for most of the items.

Conclusions: The Nottingham method of stereognosis assessment is a reliable method of stereognosis assessment.

DEBATE: WHAT DO WE THINK OF IT?

Introduction: Do we know the aim of the study? And why/how was this formed?

The aim of this study is clearly stated. The authors highlight the importance of sensation in normal movement and therefore daily life. A definition and description of of stereognosis is provided. Emphasis is placed on the exceptionally incapacitating effect of loss of stereognostic ability. The authors discuss the need for valid and reliable assessment procedures, which would assist in the identification of problem areas and thus focus treatment. A description is provided of the Nottingham Sensory Assessment (NSA) including the content, background and current stage of development building up a strong case for the current study assessing the NSA inter-rater reliability.

Methods: Is the study methodologically sound?/Should we trust it?

The authors provide a detailed description of the materials used within the test and the assessment procedures. Each patient was the subject of two assessments performed by 2 out of 3 assessors within a 24 hour period to reduce the possibility of change in the patients over-time. The order of assessor was randomised to eliminate bias. All assessors were trained in the use of the assessment tool.

Each patient was blindfolded and presented with a tray containing 10 different objects All patients were tested on their affected side first to reduce the possibility of a learning effect. The assessor assisted patients who were unable to manipulate the objects, the authors note the effect of this added sensory stimulation on the CNS.

Results: Are they expressed in terms of the likely benefits or harm that patients should expect?

The results are presented in a clear and precise manner. Results are presented in text, tables and graphs. Kappa coefficient is used to examine the reliability of the test between and among the examiners. One of the advantages of this paper is that the authors have provided a guide to interpreting the Kappa scores which makes it easier to understand.

Discussion/Conclusions: Does this study have implications for clinical practice?

The authors discuss the results of this study in some detail. The effect of ‘guidance contact’ form the assessor is considered. The absence of dysphasic and dysarthric patients from the study is highlighted. An alternative scoring system for the NSA is debated along with the possible need for a weighting system, which would reflect the difficulty, or ease with which an object could be identified. The authors conclude that the Nottingham Stereognosis Assessment measure is reliable and appropriate for use with stroke patients although it would gain from further development.

This appraisal is based on the opinions of the STEP team.