Single Case Studies-Getting the Evidence

As Dr David Price clarified in his article about research methods, Drugs and Safety, although the randomised controlled trial is considered by the medical profession as the ‘gold standard’ in drug trials, it does have its limitations, not least in the numbers needed to prove the effectiveness and safety of the drug or intervention.

There are other methods, not looked upon as favourably by the research communities, but which do have certain advantages and are gradually gaining acceptance. One such approach is what is known as the single case study or small-n research (n= number of subjects). It is important to differentiate what is meant by a case study and a single case study experiment.

Case studies are usually retrospective reports made on observations of a particular patient. In fact many of us using Aimspro are effectively writing our own case studies in the daily or weekly diaries we keep on the effects of Aimspro by noting the changes that occur in us. These are always valuable records and may hold clues for future clinical evaluations and the detailed observations that accrue can be used to develop a pool of empirical evidence.

However a single case study or experiment is somewhat different. Instead of a report of what happened, as in the Case Study, the researcher is looking at an individual and the effect the intervention (in this example Aimspro) has on a number of variables – signs and symptoms – so that any changes that occur can be recorded accurately. It can be seen that a number of well -recorded and objective single case studies could collectively provide useful baseline data for the evaluation of a treatment .

As the results of the single case study focus on the individual rather than the average person, in-depth data from a number of individuals may be more reliable than that from a larger group studied superficially. Both quantitative and qualitative methods can be used to generate data that can be analysed in a number of ways. Quantitative data would involve repeated measurements of defined variables in a single person over time– for example the range of active movement in a stiff joint, the severity of spasticity, or frequency of incontinence.

A problem with this approach is associated with obtaining repeated accurate measurements of variables such as pain, spasticity, frequency of incontinence or functional activities. So it is essential that comprehensive baseline data be collected before the treatment begins. Ideally this would mean a full physical assessment by a specialist practitioner in the appropriate discipline (For MS for example, a neurologist or a neuro-physiotherapist) followed by regular reassessments.

There is still value in the qualitative recording of more subjective data through questionnaires and semi-structured interviews. The information gained from the reported experiences, attitudes and judgements of the individual subjects provides rich data that can be subsequently analysed to find key words and common themes that the investigator use to generate theories that might be more widely generalisable.

Each of us in the fortunate position of receiving a treatment as a ‘special’ should consider ourselves suitable research subjects and make sure that we keep accurate diaries recording every change that occurs whilst on the treatment. I know that many of you have developed your own way of recording changes so that the diary is easy to keep, accurate and informative to another reader. If you have examples of such record-keeping methods that you would like to share, please contact me. Perhaps we can assemble a record-keeping format that everyone could use that would be of value to researchers.

Notes

Author - Gillian Jordan

Background - Gillian Jordan has an inflammatory condition known as Adhesive Arachnoiditis, as well as Syringomyelia. This results in a range of unpleasant symptoms, probably familiar to many of you with similar conditions. They include severe pain in both legs, flexor and adductor spasticity, increasing leg weakness, numbness in both feet, bladder and bowel dysfunction and episodes of profound and unpleasant sweating.

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