Outcome measurement in functional neurological disorder: a systematic review and recommendations, 2020, Pick et al

Andy

Andy

Retired committee member
Chalder and Stone are among the authors of this.
Objectives We aimed to identify existing outcome measures for functional neurological disorder (FND), to inform the development of recommendations and to guide future research on FND outcomes.

Methods A systematic review was conducted to identify existing FND-specific outcome measures and the most common measurement domains and measures in previous treatment studies. Searches of Embase, MEDLINE and PsycINFO were conducted between January 1965 and June 2019. The findings were discussed during two international meetings of the FND-Core Outcome Measures group.

Results Five FND-specific measures were identified—three clinician-rated and two patient-rated—but their measurement properties have not been rigorously evaluated. No single measure was identified for use across the range of FND symptoms in adults. Across randomised controlled trials (k=40) and observational treatment studies (k=40), outcome measures most often assessed core FND symptom change. Other domains measured commonly were additional physical and psychological symptoms, life impact (ie, quality of life, disability and general functioning) and health economics/cost–utility (eg, healthcare resource use and quality-adjusted life years).

Conclusions There are few well-validated FND-specific outcome measures. Thus, at present, we recommend that existing outcome measures, known to be reliable, valid and responsive in FND or closely related populations, are used to capture key outcome domains. Increased consistency in outcome measurement will facilitate comparison of treatment effects across FND symptom types and treatment modalities. Future work needs to more rigorously validate outcome measures used in this population.
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Open access, https://jnnp.bmj.com/content/early/2020/02/28/jnnp-2019-322180
 
Their recommended outcomes (table 4) are all self-report questionnaires, aside from healthcare resource use. So the aim is to get FND patients to fill in questionnaires a bit more positively and bother doctors less?

FND has features that make decisions regarding outcome measurement particularly complex.4 5 These include heterogeneity and variability of symptoms and the marked influence of attention, beliefs and expectations.6–8 Discrepancy between objective measures and patients’ subjective experiences of symptoms can also be a prominent feature.9 These aspects of FND potentially make objective ‘snapshot’ measures (eg, clinician-rated scales and objective performance tests) less reliable and valid. They also suggest that patient-rated outcomes may be particularly meaningful in this population.
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An important direction for further research is to examine the perspectives of patients, carers and other relevant stakeholders on outcome measurement in FND, particularly exploring views on the relative merits of subjective and objective measures.
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Patients go to a neurology clinic because they are experiencing neurological symptoms. The doctor finds that objective signs do not fit disease categories so they are given a diagnosis of FND

The only outcome measure for any treatments offered is that the original presenting symptoms (all the symptoms!) are gone or minimised. How is that difficult?

Nowadays they say that FND is not a disease of exclusion but can be shown by signs and brain imaging so it is easy to set objective outcomes.
 
FND has features that make decisions regarding outcome measurement particularly complex.4 5 These include heterogeneity and variability of symptoms and the marked influence of attention, beliefs and expectations.6–8 Discrepancy between objective measures and patients’ subjective experiences of symptoms can also be a prominent feature.9 These aspects of FND potentially make objective ‘snapshot’ measures (eg, clinician-rated scales and objective performance tests) less reliable and valid. They also suggest that patient-rated outcomes may be particularly meaningful in this population.

This seems plain stupid. If the problem is that outcome measures are affected by beliefs and expectations then patient-rated outcomes are going to be less reliable.
 
Jonathan Edwards said:
FND has features that make decisions regarding outcome measurement particularly complex.4 5 These include heterogeneity and variability of symptoms and the marked influence of attention, beliefs and expectations.
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I had to laugh when I read this. It sounds like they are observing that attention, beliefs and expectations influence how people report their symptoms and they interpret that as sign the illness is mysteriously arising from the mind.
 
Yes.
FND has features that make decisions regarding outcome measurement particularly complex.4 5 These include heterogeneity and variability of symptoms and the marked influence of attention, beliefs and expectations.
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And the first part of that sentence is equally laughable.
If you are going to create a category of illnesses that lumps people together with 'tremor, dystonia, limb weakness, numbness and seizures' along with various
additional physical symptoms (eg, fatigue, pain, sleep disturbance, gastrointestinal and urological problems)
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then don't be surprised if people laugh at you when you bleat about the complex situation you have to cope with because of the heterogeneity and variability of symptoms.
 
strategist said:
I had to laugh when I read this. It sounds like they are observing that attention, beliefs and expectations influence how people report their symptoms and they interpret that as sign the illness is mysteriously arising from the mind.
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Yesterday upon the stair
I met an illness that wasn't there
(According to SF36) it wasn't there again today
But Dr Stone will make it go away!
 
The patient enters the room and rates their SF36 score as 60.

The patient is then subtly given the message that the illness is a product of their mind and that there isn't anything wrong with their body and that they shouldn't view their symptoms the way they do now.

Before leaving, the patient rates themselves at 70. The therapist is thrilled at their own ability to treat psychosomatic disease and is pleased to once again have seen confirmation that it can be treated by manipulating the patient's cognition.
 
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strategist said:
The patient enters the room and rates their SF36 score as 60.

The patient is then subtly given the message that the illness is a product of their mind and that there isn't anything wrong with their body and that they shouldn't view their symptoms the way they do now.

Before leaving, the patient rates themselves at 70. The therapist is thrilled at their own ability to treat psychosomatic disease and is pleased to once again have seen confirmation that it can be treated by manipulating the patient's cognition.
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The improvement does not correlate with objective performance tests indicating these are less reliable and valid and should, therefore, be avoided.

The treatment effect disappears at follow-up. The illness is mysterious. Booster sessions are advised. The patient needs more psychosomatic therapy.
 
strategist said:
One of the therapists, while discussing the topic with colleagues, wrings her hands and says that they could achieve even better results if the patients weren't so resistent to the therapy.
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It is determined that it is the parents (in the case of young people with MUS) and the partners (in the case of people with MUS with partners) who are facilitating this resistance. It is proposed that therapy be extended to these facilitators.
 
Hutan said:
It is determined that it is the parents (in the case of young people with MUS) and the partners (in the case of people with MUS with partners) who are facilitating this resistance. It is proposed that therapy be extended to these facilitators.
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The striking consistency of the results of trials looking into this issue further encourages the researchers that they are definitely right. They work towards proposing that most, if not all, illness fits neatly into their model of perpetuation.
 
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