From the Guidelines
Yes, clonus can occur in functional neurological disorder (FND). According to the most recent and highest quality study available, FND is diagnosed by a neurologist using ‘positive clinical signs’ (eg, Hoover’s sign, distractibility, entrainment of tremor and variability in symptoms during function) and is not a diagnosis of exclusion 1. This implies that clonus, as a symptom, can be part of the presentation of FND.
Key Characteristics of FND-Related Clonus
- Clonus in FND typically differs from organic clonus in several ways: it may be variable or inconsistent, change with distraction, have irregular rhythm, or demonstrate unusual patterns like immediate cessation when the limb is supported.
- FND-related clonus doesn't require medication treatment aimed at the clonus itself; instead, the focus should be on treating the underlying functional disorder through a multidisciplinary approach including physical therapy, psychological therapy (particularly cognitive behavioral therapy), and patient education about the condition 1.
- The neurophysiological basis for functional clonus involves abnormal brain network activity rather than the specific spinal cord or upper motor neuron pathology seen in organic clonus.
Diagnosis and Treatment Planning
Clinicians can differentiate functional from organic clonus through careful examination, looking for variability, distractibility, entrainment to external rhythms, and other features inconsistent with organic pathology 1. Understanding this distinction is important for proper diagnosis and treatment planning. Occupational therapy plays a crucial role in the management of FND, focusing on a biopsychosocial aetiological framework, education, rehabilitation within functional activity, and the use of taught self-management strategies 1.
Multidisciplinary Approach
A multidisciplinary approach is essential for the management of FND, including occupational therapy, physical therapy, psychological therapy, and patient education. This approach can help improve symptoms, quality of life, and functional outcomes for individuals with FND. Given the limited evidence base for specific rehabilitation interventions, consensus recommendations and further research are needed to guide practice and demonstrate effectiveness 1.
From the Research
Presentation of Functional Neurological Disorder (FND)
- FND is a common cause of persistent and disabling neurological symptoms 2
- It can present with various symptoms, including motor symptoms such as functional movement disorders, functional limb weakness/paresis, and functional seizures 3, 4
- The diagnosis of FND is made using "rule-in" diagnostic criteria, which include specific clinical signs and symptoms 3, 4
Clonus as a Symptom of FND
- While clonus is not explicitly mentioned as a symptom of FND in the provided studies, FND can present with a wide range of motor symptoms, including movement disorders 3, 4
- Clonus is a type of involuntary muscle contraction that can be a symptom of various neurological disorders, and it is possible that it could be a symptom of FND in some cases
- However, without further evidence, it is unclear whether clonus is a common or characteristic symptom of FND 2, 3, 4, 5, 6
Treatment of FND
- The treatment of FND typically involves a multidisciplinary approach, including physical therapy, psychotherapy, and cognitive behavioral therapy 2, 3, 4
- Neurostimulation techniques, such as transcranial magnetic stimulation and transcranial direct current stimulation, may also be effective in treating FND 5
- The goal of treatment is to reduce symptoms, improve functioning, and promote recovery, although the response to treatment can vary widely between individuals 2, 3, 4