biology

Poser criteria

Poser criteria is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Poser criteria rather than just read about it. In short: The Poser criteria are diagnostic criteria for multiple sclerosis (MS). They replaced the older Schumacher criteria.

Key takeaways

Poser criteria belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Poser criteria to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Poser criteria from memory before moving on to harder problems.

Reference excerpt

The Poser criteria are diagnostic criteria for multiple sclerosis (MS). They replaced the older Schumacher criteria. They have in turn been superseded by the McDonald criteria. Nevertheless, some of the concepts introduced have remained in MS research, like CDMS (clinical definite MS), and newer criteria are often calibrated against them. The criteria were unveiled in the Annals of Neurology in 1983 by a team led by Dr. Charles M. Poser. The article that introduced them also defined the concepts of attack, historical information, clinical evidence, paraclinical evidence, lesion typical of MS, remission, separate lesions and laboratory support, which are necessary to apply the criteria. The criteria considers MS as the presence of demyelinating lesions disseminated in time and space, and they are oriented specially to prove the dissemination. Based on this, the authors defined a set of rules that can yield five conclusions: CDMS, LSDMS, CPMS, LSPMS or noMS. Poser diagnosis of CDMS is known to have a sensitivity of 87% respect postmortem autopsy examination

Definitions Poser et al. define several concepts. The most important for diagnosis are:

Attack: Occurrence of a symptom of neurological dysfunction for more than 24 hours Clinical evidence: Neurological dysfunction demonstrable by neurological examination Paraclinical evidence: Demonstration by any test of the existence of a non-clinical lesion in the CNS

Diagnosis conclusions The criteria can yield five conclusions:

Summary of requirements Any of the five conclusions have subpossibilities. Here a table is shown with each one of them:

If none of these requirements is accomplished, the diagnosis is "No MS", meaning that there is not enough clinical evidence to support a clinical diagnosis of MS.

Sensitivity and specificity Poser diagnosis of CDMS was initially reported to have a sensitivity of 87% respect postmortem autopsy examination. Poser criteria were published in 1983 and their sensitivity increased with time. For example, in 1988 a 94% specificity vs. postmortem analysis was reported Anyway, in initial cases, the sensitivity was low respect pathologically defined MS because around 25% of MS cases are silent MS cases. Two pathologically disseminated inflammatory demyelinating lesions should be considered MS even if they are silent. Therefore, Poser criteria should be considered as deprecated.

Extension of the concepts As more knowledge about the underlying pathology of MS has been gathered, the concepts of subclinical, preclinical and CIS have been used together with the Poser original classification. The first manifestation of MS is the so-called clinically isolated syndrome, or CIS, which is the first isolated attack. The Poser diagnosis criteria for MS does not allow doctors normally to give an MS diagnosis until a second attack takes place. Therefore, the concept of "clinical MS", for a MS that can be diagnosed is sometimes too strong because until MS diagnosis has been established, nobody can tell whether the disease dealing with is MS. Cases of MS before the CIS are sometimes found during other neurological inspections and are referred to as "subclinical MS". "Preclinical MS" refers to cases after the CIS but before the confirming second attack. After the second confirming attack the situation is referred to as CDMS (clinically defined multiple sclerosis).

References

Worked examples

Example 1 — a first encounter with Poser criteria

Start with the simplest possible case. Write down what Poser criteria claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Poser criteria before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Poser criteria ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Poser criteria

In research: Poser criteria appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Poser criteria in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Poser criteria is common in secondary-school and first-year university syllabi. It links to neighbouring topics Autoimmune diseases, Multiple sclerosis, Neurobiological brain disorders, so understanding it makes those chapters shorter.
In everyday life: Look for Poser criteria outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Poser criteria in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Poser criteria means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Poser criteria out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Poser criteria in simple terms?

The Poser criteria are diagnostic criteria for multiple sclerosis (MS). They replaced the older Schumacher criteria.

Why does Poser criteria matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Poser criteria?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Poser criteria.