Activities of daily living (ADL)

This phrase refers to activities or tasks undertaken as part of day-to-day life such as getting dressed, cooking or shopping. They can be subdivided into personal ADL, domestic (household) ADL, and community ADL.

Adverse events

Sometimes known as side effects. Adverse events are any event that is not to the benefit of the person. Some are predictable, and some are only rare and unexpected. Adverse events from drugs might include, for example, rashes, feeling fatigued and being depressed. Adverse events can also follow rehabilitation treatments and might include falling while learning to walk and pain from stretching a joint.

Allied health professionals

Health care professionals, other than doctors and nurses, directly involved in the provision of health care. Includes several groups such as physiotherapists, occupational therapists, dieticians, etc. (Also known as professions allied to medicine or PAMs.)

Alternative therapies

A term that is difficult to define because the classification of therapies is not fixed. This usually refers to treatments of any type which are not prescribed or recommended by doctors, or are not given by health care professionals practicing within the NHS.


The extent to which the results of a study or review can be applied to the target population for a clinical guideline.

Appraisal of evidence

Formal assessment of the quality of research evidence and its relevance to the clinical question or guideline under consideration, according to predetermined criteria.

Area under curve (AUC)

See receiver operating curve (ROC).

Association of British Neurologists (ABN)

The professional body to which all neurological specialist physicians belong.


Anti-thymus globulin.


Systematic errors in the design and execution of a study which may lead to an over- or underestimation of the ‘true’ effect of a treatment or intervention.


The practice of keeping the investigators or subjects of a study ignorant of the group to which a subject has been assigned or of the population from which the subject has come. For example, a clinical trial in which the participating patients or their doctors are unaware of whether they are taking the experimental drug or a placebo (dummy treatment). The purpose of ‘blinding’ is to protect against bias.

British National Formulary (BNF)

The BNF is the recognised authoritative source of up-to-date information on drugs and pharmaceutical products for health care professionals. The emphasis is on those that are prescribed in the UK, rather than over-the-counter medicines. It is a joint publication of the British Medical Association (BMA) and the Royal Pharmaceutical Society of Great Britain (RPSGB).


Complementary and alternative medicine, eg acupuncture, homeopathy.

Cardiorespiratory fitness

The extent to which the heart and lungs are able to respond to demand. Fitness depends upon a) muscles, primarily in the legs and b) the heart and lungs.

Case-control study

A study that starts with the identification of a group of individuals sharing the same characteristics (eg people with a particular disease) and a suitable comparison (control) group (eg people without the disease). All subjects are then assessed with respect to other factors, such as things that happened to them in the past, eg things that might be related to getting the disease under investigation.

Ceiling effects

See floor and ceiling effects.

Cerebro-spinal fluid (CSF)

Fluid produced in hollow structures within the brain that circulates around the outside of the brain and also down the spinal canal. CSF is removed when a lumbar puncture is undertaken.

Clinical audit

A systematic process for setting and monitoring standards of clinical care. Patients’ notes and other clinical records are examined as part of the audit process. Clinical audit should cover the practice of all relevant health care professional groups, as opposed to medical audit which only looks at the doctor’s role in patient care. Whereas ‘research’ defines what the best clinical practice should be, ‘audit’ investigates whether best practice is being carried out.

Clinical effectiveness

How well a drug, treatment or package of care works to produce good outcomes for patients.

Clinical importance

The importance of a particular guideline recommendation compared with other aspects of clinical management that may be under consideration.

Clinical trial

Research study conducted with patients, usually to evaluate a new treatment or drug. Each trial is designed to answer scientific questions and to find better ways to treat individuals with a specific disease. See also randomised controlled trial.


A health care professional providing patient care, eg a doctor, nurse or physiotherapist.

Cochrane Library

The Cochrane Library consists of a regularly updated collection of evidence-based medicine databases including the Cochrane Database of Systematic Reviews (reviews of randomised controlled trials prepared by the Cochrane Collaboration). The Cochrane Library is available on CD-ROM and on the Internet.

Cognitive status

Cognition refers to the processes involved in thinking, concentrating, planning, solving problems, learning, analysing sensations and remembering. A person’s cognitive status is the extent to which they can use their brain to undertake these processes.

Cohort study

A cohort study takes a group of patients and follows them forward in time and measures their outcome (eg disease or mortality rates). Patient subgroups are then identified from information collected about patients and these groups are compared with respect to outcome, eg comparing mortality between one group that received a specific treatment and one group which did not (or between two groups that received different levels of treatment). Cohorts can be assembled in the present and followed into the future (a ‘concurrent cohort study’) or identified from past records and followed forward from that time up to the present (a ‘historical cohort study’). Because patients are not randomly allocated to the two groups, the groups may be quite different in their characteristics and some adjustment must be made when analysing the results to ensure that the comparison between groups is as fair as possible.


In legal terms, this refers to the ability of someone to make an informed judgement and it depends upon being able to understand written or spoken material sufficiently, hold the information in the memory and use the material to make a considered judgement.

Complementary therapies

See alternative therapies.

Computerised tomography (CT)

A technique whereby X-rays are used to map the inside of the body, especially the brain.

Confidence interval

This helps us assess the likely effect of a clinical intervention by describing a range of possible effects that are consistent with the results of a study (or of a combination of studies). A wide confidence interval indicates a lack of certainty or precision about the true size of the clinical effect and is seen in studies with too few patients. Where confidence intervals are narrow they indicate more precise estimates of effects and a larger sample of patients studied. We usually interpret a 95% confidence interval as the range of effects within which we are 95% confident that the true effect lies.

Confounding factor

Something that introduces uncertainty and bias into an observed outcome, complicating interpretation.

Consensus methods

A variety of techniques that aim to reach an agreement on a particular issue. Formal consensus methods include Delphi and nominal group techniques, and consensus development conferences. In the development of clinical guidelines, consensus methods may be used where there is a lack of strong research evidence on a particular topic.


The extent to which the conclusions of a collection of studies used to support a guideline recommendation are in agreement with each other. See also homogeneity.

Control group

A group of patients recruited into a study that receives no treatment, a treatment of known effect, or a placebo (dummy treatment) – in order to provide a comparison for a group receiving an experimental treatment, such as a new drug.

Controlled clinical trial (CCT)

A study that includes some form of control that is not randomised.


A measure of the strength of association between two or more variables. For example in children height, weight and age are all correlated because older children tend to be taller and heavier. A positive correlation indicates that one variable has been observed to increase as the other increases, a negative correlation indicates that one decreases as the other increases.

Cost-benefit analysis

A type of economic evaluation where both costs and benefits of health care treatment are measured in the same monetary units. If benefits exceed costs, the evaluation would recommend providing the treatment.


How expensive treatment and care are compared to how much benefit they offer to patients. In cost-effectiveness analysis, the outcomes of different interventions are converted into health gains for which a cost can be associated, for example, cost per additional heart attack prevented.

Crossover study design

The administration of two or more experimental treatments one after the other in a specified or random order to the same group of patients.

Decision analytic model

A method, in health economics, of establishing the best course of action when evidence, both clinical and cost, is uncertain.

Department of Health

A generic term for four UK government departments responsible for the health and well-being of people in England, Wales, Scotland and Northern Ireland, and having specific responsibility for the National Health Service (NHS) and Social Services Inspectorate (SSI).


District general hospital (non-teaching hospital).

Diagnostic odds ratio (DOR)

DOR is used as a summary measure of the accuracy of a diagnostic test. It is calculated as the odds of a correct positive result, divided by the odds of a false positive result. When a test provides no diagnostic evidence then the DOR is 1.0, but a valuable diagnostic test will tend to have a high DOR.

Diagnostic study

Any research study aimed at evaluating the utility of a diagnostic procedure. The methods employed are generally different to those in a clinical trial aimed at evaluating an intervention.

Diagnostic work-up

The process of making a diagnosis through tests, clinical history and clinical judgement.

Disease modifying therapies (DMTs)

Any treatment that slows down, stops or reverses the processes that damage the nervous system in MS.

Disease progression

This specifically refers to increasing damage to the nervous system. There is only a weak relationship between damage to the nervous system and increasing symptoms or signs. And some episodes of worsening are simply due to another illness (eg bladder infection) and not progression of the damage to the nervous system.


An economic term for an intervention which is cheaper and clinically more effective than the alternative(s).


Difficulty of articulating words caused by disease of the central nervous system, typically characterised by slurred speech, imprecise articulation and disorders of intonation.

Economic evaluation

Comparative analysis of alternative courses of action in terms of both their costs and consequences.


The extent to which a specific treatment or intervention, when used under usual or everyday conditions, does what it is intended to do, eg control or cure an illness. (Clinical trials that assess effectiveness are sometimes called ‘management trials’.)


The ability of a drug or other treatment to control or cure an illness. In research terms, ‘efficacy’ refers to the extent to which a specific intervention produces the intended (beneficial) result under ideally controlled conditions, eg in a laboratory.

Episode of care

A technical, Department of Health term that refers to the whole of a treatment episode from hospital admission to discharge or from starting to stopping a course of treatment.


The process of systematically finding, appraising, and using research findings as the basis for clinical decisions.

Evidence table

A table summarising the results of a collection of studies which, taken together, represent the evidence supporting a particular recommendation or series of recommendations in a guideline.

Evoked potentials

Electrical changes in the brain that follow stimulation of the nervous system. The commonest example is to flash lights in the eyes, when an electrical change will occur over the occiput (back of the head) about 1/10th of a second later. They can only be detected using computers and many repeated stimulations because the potentials are so small.

Experimental study

A research study designed to test if a treatment or intervention has an effect on the course or outcome of a condition or disease.


The application of research evidence based on studies of a specific population to another population with similar characteristics.

Floor and ceiling effects

Problems encountered in some outcome measures where there are limits to how low or high a numerical value they can assume, eg it is impossible to measure more than 100%. These can make it difficult to assess the true effect of an intervention.

Focus groups

Method of group interview or discussion of between 6 and 12 people focused around a particular issue or topic. The method explicitly includes and uses the group interaction to generate data.

Functional status

An individual’s ability to continue normal social and physical activities.

Grade of recommendation

A code (eg A, B, C) linked to a guideline recommendation, indicating the strength of the evidence supporting that recommendation.


A systematically developed tool which describes aspects of a patient’s condition and the care to be given. A good guideline makes recommendations about treatment and care, based on the best research available, rather than opinion. It is used to assist clinician and patient decision making about appropriate health care for specific clinical conditions.

Guideline recommendation

Course of action advised by the guideline development group on the basis of their assessment of the supporting evidence.

Health technology

Health technologies include medicines, medical devices such as artificial hip joints, diagnostic techniques, surgical procedures, health promotion (eg the role of diet vs medicines in disease management) and other therapeutic interventions.

Health technology appraisal (HTA)

A health technology appraisal, as undertaken by NICE, is the process of determining the clinical and cost-effectiveness of a health technology. NICE health technology appraisals are designed to provide patients, health professionals and managers with an authoritative source of advice on new and existing health technologies.


Or lack of homogeneity. The term is used in meta-analyses and systematic reviews when the results or estimates of effects from separate studies seem to have different magnitude or even different sign or direction. Differences in the patient populations, outcome measures, definition of variables and duration of follow-up of the studies included in the analysis create problems of non-compatibility. See also homogeneity.

Hierarchy of evidence

An established hierarchy of study types, based on the degree of certainty that can be attributed to the conclusions of a well-conducted study. Well-conducted randomised controlled trials (RCTs) are at the top of this hierarchy. (Several large statistically significant RCTs which are in agreement represent stronger evidence than, say, one small RCT.) Well-conducted studies of patients’ views and experiences would appear at a lower level in the hierarchy of evidence. See also randomised controlled trial.

History, clinical

The information collected and considered by a health care professional regarding an individual’s previous health-related experiences.


This means that the results of studies included in a systematic review are similar and there is no evidence of heterogeneity. Results are usually regarded as homogeneous when differences between studies could reasonably be expected to occur by chance. See also consistency, heterogeneity and systematic review.


See health technology appraisal.


Caused by a health care treatment.


The rate of new occurrences of a condition or disease, often given as people per year or episodes per year.

Inclusion criteria

See selection criteria.

Intention to treat analysis

An analysis of a clinical trial where patients are analysed according to the group to which they were initially randomly allocated, regardless of whether or not they had dropped out, fully complied with the treatment, or crossed over and received the alternative treatment.


Health care action intended to benefit the patient, eg prescribing drugs, surgical procedures, psychological therapy, etc.

Intervention groups

In a clinical trial, groups to which participants are allocated. Typically, these groups will receive different interventions or a placebo.

Level of evidence

A code (eg 1a, 1b) linked to an individual study, indicating where it fits into the hierarchy of evidence and how well it has adhered to recognised research principles. See also hierarchy of evidence.

Literature review

A process of collecting, reading and assessing the quality of published (and unpublished) articles on a given topic.

Local protocols

See protocol.

Low vision service

Any local health service provided to cater for people experiencing visual problems.

Magnetic resonance imaging (MRI)

An imaging technique which uses powerful magnetic fields rather than radiation to obtain accurate images of soft tissue inside the body. Some people cannot safely be scanned with MRI, for example those with pacemakers.


Results from a collection of independent studies are pooled, using statistical techniques to synthesise their findings into a single estimate of a treatment effect. A systematic review may or may not include a meta-analysis. It is always appropriate and desirable to systematically review a series of results but it may sometimes be inappropriate, or even misleading, to statistically pool results from separate studies. See also systematic review and heterogeneity.

Methodological quality

The extent to which a study has conformed to recognised good practice in the design and execution of its research methods.

Methodological weakness

Any problem in the way in which a study has been conducted, which throws doubt on the conclusions. See methodological quality.


The overall approach of a research project, eg the study will be a randomised controlled trial, of 200 people, over one year. See also randomised controlled trial.

Multimodal intervention

An intervention comprised of more than one aspect which can affect outcomes for the patient.

Musculo-skeletal pain

Pain arising from the muscular and skeletal systems, as distinct from neurogenic pain.

National Institute for Clinical Excellence (NICE)

NICE is a special health authority responsible for providing patients, health professionals and the public with authoritative, robust and reliable guidance on current ‘best practice’. NICE commissioned and funded the development of this guideline.


Arising from the nervous system.


Pertaining to disorders of the nervous system.

Non-experimental study

A study based on subjects selected on the basis of their availability, with no attempt having been made to avoid problems of bias.

Objective measure

A measurement that follows a standardised procedure which is less open to subjective interpretation by potentially biased observers and study participants.

Odds ratio

Odds are a way of representing probability, especially familiar for betting. In recent years odds ratios have become widely used in medical reports. They provide an estimate (usually with confidence interval) for the effect of an intervention. Odds are used to convey the idea of ‘risk’ and an odds ratio of 1 between two treatment groups would imply that the risks of an adverse outcome were the same in each group. For rare events the odds ratio and the relative risk (which uses actual risks and not odds) will be very similar. See also control group, relative risk.

Oligoclonal banding

A phenomenon which can be detected by testing cerebro-spinal fluid. It can help to diagnose MS.

Optic neuritis

Inflammation of the optic nerve, which carries visual information from the eye to the brain.

Orthodox therapies

See also alternative therapies. Any medical or physical therapy which is usually used or recommended by health care professionals working within the NHS


The end result of care and treatment and/or rehabilitation. In other words, the change in health, functional ability, symptoms or situation of a person, which can be used to measure the effectiveness of care/treatment/rehabilitation. Researchers decide what outcomes to measure before a study begins. Outcomes are then assessed at the end of the study.

Palliative care

Care aimed at alleviating symptoms, pain and distress, and hence improving quality of life, rather than at curing or slowing progression of a disease or condition. It is often associated with, but is actually not limited to, the end of life.


See primary care trust.

Pilot study

A small scale ‘test’ of the research instrument. For example, testing (piloting) a new questionnaire with people who are similar to the population of the study, in order to highlight any problems or areas of concern, which can then be addressed before the full-scale study begins.


A pill, medicine, or other treatment that has no physiological effect and is used as a dummy treatment. A placebo may be used as a comparison (control) in tests on new drugs etc.

Placebo effect

A beneficial (or adverse) effect produced by a placebo and not due to any property of the placebo itself. See placebo.

Pooled estimate

An estimate of the effect of a treatment, arrived at through a meta-analysis.


After childbirth.

Pre-post study

A study design which measures outcomes in one group of people, first before, and then after, an intervention is given or initiated.


The proportion of a population of people who are experiencing a condition or disease at a given time.

Primary care

Health care delivered to patients outside hospitals. Primary care covers a range of services provided by GPs, nurses and other health care professionals, dentists, pharmacists and opticians.

Primary care trust

A primary care trust is an NHS organisation responsible for improving the health of local people, developing services provided by local GPs and their teams (called primary care) and making sure that other appropriate health services are in place to meet local people’s needs.

Prior probability

In a diagnostic study, the proportion of the population which has the condition in question, regardless of what the test result subsequently is.


How likely an event is to occur, eg how likely a treatment or intervention will alleviate a symptom.

Prognostic factor

Patient or disease characteristics which influence the course of a particular condition. In a randomised trial to compare two treatments, chance imbalances in variables (prognostic factors) that influence patient outcome are possible, especially if the size of the study is fairly small. In terms of analysis these prognostic factors become confounding factors. See confounding factor.

Prospective study

A study in which people are entered into the research and then followed up over a period of time with future events recorded as they happen. Prospective studies may be of several types, including cohort or randomised controlled trials. See cohort study and randomised controlled trial.


A policy or strategy which defines appropriate action. A research protocol sets out, in advance of carrying out the study, what question is to be answered and how information will be collected and analysed. Guideline implementation protocols set out how guideline recommendations will be used in practice by the NHS, at both national and local levels.


If a study is done to compare two treatments then the P-value is the probability of obtaining the results, or something more extreme, if there really was no difference between treatments. Suppose P = 0.03. What this means is that if there really was no difference between treatments then there would only be a 3% chance of getting the kind of results obtained. Since this chance seems quite low we should question the validity of the assumption that there really is no difference between treatments. We would conclude that there probably is a difference between treatments. By convention, where the value of P is below 0.05 (ie less than 5%) the result is seen as statistically significant. Where the value of P is 0.001 or less, the result is seen as highly significant. P values just tell us whether an effect can be regarded as statistically significant or not. In no way do they relate to how big the effect might be, for which we need the confidence interval.

Qualitative methods

Research techniques used to describe life’s experiences and give them meaning, using a systematic, subjective approach. This type of research is conducted in order to describe and promote understanding of people’s experiences, feelings, motivations and behaviour. Examples of qualitative methods include focus groups, in-depth interviews and participant observation. These techniques generate non-numerical data, eg a patient’s description of their pain rather than a measure of pain.

Quality-adjusted life years (QALYs)

A measure of health outcome. QALYs are calculated by estimating the total life-years gained from a treatment and weighting each year with a quality of life score.

Quantitative methods

Research techniques that generate numerical data or data that can be converted into numbers. For example, census questions such as the number of people living in a household.

Quasi-experimental study

This is a study in which the treatment comparison groups are not assigned by randomisation.

Randomised controlled trial

A trial in which people are randomly assigned to two (or more) groups: one (the experimental group) receiving the treatment that is being tested, and the other (the comparison or control group) receiving an alternative treatment, a placebo (dummy treatment) or no treatment. The two groups are followed up to compare differences in outcomes to see how effective the experimental treatment was.

Receiver operating curve (ROC)

A mathematical method of comparing diagnostic procedures involving their specificity and sensitivity. The closer the area under the curve (AUC) is to 1, the better the test.

Reference standard

In diagnostic studies, the test being evaluated is often compared to the best known diagnostic procedure, which is known as the reference standard or gold standard.


Rehabilitation is a process that focuses on ability and aims to optimise social participation and to minimise distress and stress for both the person with MS and any carers involved, mainly through a problem-solving approach that will involve multi-focal interventions from a specialist team over time.

Relative risk

A summary measure which represents the ratio of the risk of a given event in group of subjects compared to another group. When the ‘risk’ of the event of interest is the same in the two groups the relative risk is 1. Relative risk is sometimes used as a synonym for risk ratio. In a treatment comparison study a relative risk of 2 would indicate that patients receiving one of the treatments had twice the risk of an undesirable outcome than those receiving the other treatment.

Relative risk-benefit ratio

A method of comparing two interventions, balancing the risk and benefit of each to a defined population.


Reliability refers to a method of measurement that consistently gives the same results. For example, someone who has a high score on one occasion tends to have a high score if measured on another occasion very soon afterwards. With physical assessments it is possible for different clinicians to make independent assessments in quick succession – and if their assessments tend to agree then the method of assessment is said to be reliable.


Summary of the main points and trends in the research literature on a specified topic. A review is considered non-systematic unless an extensive literature search has been carried out to ensure that all aspects of the topic are covered and an objective appraisal made of the quality of the studies.


A part of the study’s target population from which the subjects of the study will be recruited. If subjects are drawn in an unbiased way from a particular population, the results can be generalised from the sample to the population as a whole.


Refers to the way participants are selected for inclusion in a study.


Conditions and symptoms which are brought about by an existing disease or condition are described as secondary. For example, secondary pain can result from restrictions in mobility because of MS. The pain in this case is secondary to the MS.

Secondary care

Care provided in hospitals.

Selection criteria

Explicit criteria used by guideline development groups to decide which studies should be included and excluded from consideration as potential sources of evidence.

Self-report measure

An outcome measure which uses the views and experience of the person with MS rather than clinical measurements.


The sensitivity of a diagnostic test is the proportion of people with MS who, when tested, have a true positive result.

Sensitivity analysis

A mathematical process, often employed in good quality health economics studies, which assesses the sensitivity of the conclusions to inaccuracy in the estimates regarding cost, clinical effectiveness of the treatments, and the structure of the health service.


A condition occurring as a consequence of a disease.

Significance, statistical

Also ‘significant difference’ or ‘significant effect’.


Health care professional with relevant qualifications, necessary knowledge and skills.


The specificity of a diagnostic test is the proportion of people without MS who, when tested, have a true negative result.


Any national organisation, including patient and carers’ groups, health care professionals and commercial companies with an interest in the guideline under development.

Standard deviation

A measure of the spread, scatter or variability of a set of measurements. Usually used with the mean to describe numerical data.


A study in which information is systematically collected from people (usually from a random sample within a defined population).


Methodical, according to plan; not random.

Systematic review

A review in which evidence from scientific studies has been identified, appraised, and synthesised in a methodical way according to predetermined criteria. May or may not include a meta-analysis.


Involving the whole body.

Tertiary centre

A major medical centre providing complex treatments, which receives referrals from both primary and secondary care. Sometimes called a tertiary referral centre. See also primary care and secondary care.

Transverse myelitis

Inflammation with neurological symptoms, caused by lesions on the spinal cord.

Trial of treatment

A planned period during which a person with MS receives a treatment to find out if it will be of benefit to them as individuals.


A trust is an NHS organisation responsible for providing a group of health care services. An acute trust provides hospital services. A mental health trust provides most mental health services. A primary care trust buys hospital care on behalf of the local population, as well as being responsible for the provision of community health services.


Assessment of how well a tool or instrument measures what it is intended to measure. See also external validity, internal validity.


A concept combining an individual’s health, their quality of life, and their satisfaction. There is no universally agreed definition that is useful in the context of health care.