From the Guidelines
The diagnostic approach for Functional Neurological Disorder (FND) involves a positive diagnosis based on specific clinical findings, such as Hoover's sign, distractibility, entrainment of tremor, and variability in symptoms during function, rather than simply ruling out other conditions. This approach is supported by the most recent and highest quality study, which emphasizes the importance of demonstrating inconsistency and incongruity in neurological symptoms 1. The diagnosis of FND should be made by a neurologist experienced in FND, ideally in a multidisciplinary setting, and should not be based solely on the exclusion of other neurological conditions.
Some key points to consider in the diagnostic approach for FND include:
- The use of specific tests, such as Hoover's sign, the hip abductor sign, drift without pronation, give-way weakness, and tremor entrainment or distractibility tests, to demonstrate inconsistency and incongruity in neurological symptoms
- The use of neuroimaging, such as MRI, to exclude structural lesions rather than confirm FND
- The use of neurophysiological tests, such as electromyography, to help distinguish functional from organic disorders in some cases
- The importance of psychological assessment, but not as a diagnostic tool on its own
- The need for a transparent diagnostic process, explaining to the patient that FND is a real neurological condition involving brain network dysfunction rather than a purely psychological problem
It is also important to note that FND can be diagnosed alongside other neurological conditions, and that early diagnosis is crucial to improve treatment outcomes and prevent iatrogenic harm from unnecessary interventions 1. Additionally, the diagnostic approach for FND should be based on a biopsychosocial aetiological framework, and should involve education, rehabilitation, and the use of taught self-management strategies 1.
In terms of specific treatment approaches, the use of occupational therapy, speech and language therapy, and other multidisciplinary interventions may be beneficial in managing FND symptoms 1. However, the most important factor in the diagnostic approach for FND is the use of positive clinical signs to demonstrate inconsistency and incongruity in neurological symptoms, rather than simply ruling out other conditions.
From the Research
Diagnostic Approach for Functional Neurological Disorder (FND)
The diagnostic approach for FND involves a comprehensive clinical assessment, taking into account the patient's physical, psychological, and social presentation 2. The primary purpose of the assessment is to make a diagnosis and develop a treatment plan, while also setting a tone and context for future clinical interactions.
Key Components of the Diagnostic Approach
- A positive diagnosis of FND can be made on the basis of history and neurological signs without reliance on psychological stressors 3
- Classification of FND emphasizes the importance of positive diagnosis based on physical signs, not psychological features 4
- The diagnosis should rest on clear positive evidence, typically from a combination of physical signs on examination or the nature of seizures 5
- Common diagnostic pitfalls include features that lead to erroneous diagnosis of neurologic disease, such as old age, la belle indifférence, and lack of psychiatric comorbidity 2
Importance of Multidisciplinary Approach
- A multidisciplinary approach, involving neurologists, psychiatrists, psychologists, and physical therapists, is beneficial in the diagnosis and treatment of FND 4, 5
- Clear communication of the diagnosis and involvement of the multidisciplinary team is essential in the treatment of FND 5