Multimodal Brain Analysis of Functional Neurological Disorders: A Functional Stroke Mimic Case Series

Premi, Enrico; Benussi, Alberto; Compostella, Silvia; Gilberti, Nicola; Vergani,; Delrio, Ilenia; Spezi, Raffaella; Gamba, Massimo; Costa, Angelo; Gasparotti, Roberto; Magoni, Mauro; Padovani, Alessandro; Borroni, Barbara

doi:10.1159/000465524

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…Findings included increased RMT in the affected M1, compared both to the unaffected side and healthy controls. Moreover, the authors found increased SICI in the affected hemisphere compared to the contralateral one (similar to a previous study by the same group [23]), increased SICI in the affected side and decreased SICI in the unaffected side compared to controls. The increased inhibition in the affected M1 and asymmetry of SICI between the two M1 were proposed by the authors to be disease-specific electrophysiological findings to support the clinical diagnosis of FP.…”

Section: Pathophysiology Of Functional Paralysis Investigated By Tran...supporting

confidence: 88%

Pathophysiology and Treatment of Functional Paralysis: Insight from Transcranial Magnetic Stimulation

et al. 2023

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Functional paralysis (FP) or limb weakness is a common presentation of functional movement disorders (FMD), accounting for 18.1% of the clinical manifestations of FMD. The pathophysiology of FP is not known, but imaging studies have identified changes in structural and functional connectivity in multiple brain networks. It has been proposed that noninvasive brain stimulation techniques may be used to understand the pathophysiology of FP and may represent a possible therapeutic option. In this paper, we reviewed transcranial magnetic stimulation studies on functional paralysis, focusing on their pathophysiological and therapeutical implications. Overall, there is general agreement on the integrity of corticospinal pathways in FP, while conflicting results have been found about the net excitability of the primary motor cortex and its excitatory/inhibitory circuitry in resting conditions. The possible involvement of spinal cord circuits remains an under-investigated area. Repetitive transcranial magnetic stimulation appears to have a potential role as a safe and viable option for the treatment of functional paralysis, but more studies are needed to investigate optimal stimulation parameters and clarify its role in the context of other therapeutical options.

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Section: Pathophysiology Of Functional Paralysis Investigated By Tran...supporting

confidence: 88%

Pathophysiology and Treatment of Functional Paralysis: Insight from Transcranial Magnetic Stimulation

et al. 2023

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“…To this, further studies should assess cortical excitability in the acute phase of symptoms' onset. Supporting these findings and arguing for a causal role of increased SICI in functional hemiparesis are previous findings observed at only 1 month after symptom onset in patients with functional paralysis (Premi et al, 2017). Moreover, these findings should be compared with patients with organic hemiparesis (i.e., after stroke), in order to shed further light on disease pathophysiology.…”

Section: Discussionsupporting

confidence: 67%

“…One of these studies, performed on 3 patients with flaccid paralysis, did not observe any significant differences in SICI or ICF between the affected and unaffected side (Liepert et al, 2008). Subsequently, another study performed on 4 patients with functional paralysis showed a significant increase in SICI and a non-significant increase in RMT in the affected side compared to healthy controls (Premi et al, 2017).…”

Section: Discussionmentioning

confidence: 98%

“…A possible marker could reside in the functional evaluation of the motor cortex, but mixed results have been reported regarding motor cortex excitability and intracortical inhibitory circuits, evaluated with transcranial magnetic stimulation (TMS) (Premi et al, 2017). These studies were performed in small groups of patients, including both flaccid and spastic-dystonic paralysis.…”

Section: Introductionmentioning

confidence: 99%

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Cortical Inhibitory Imbalance in Functional Paralysis

Benussi

Premi

Cantoni

et al. 2020

Front. Hum. Neurosci.

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Background: Functional neurological disorders are characterized by neurological symptoms that have no identifiable pathology and little is known about their underlying pathophysiology. Objectives: To analyze motor cortex excitability and intracortical inhibitory and excitatory circuits' imbalance in patients with flaccid functional weakness. Methods: Twenty-one consecutive patients with acute onset of flaccid functional weakness were recruited. Single and paired-pulse transcranial magnetic stimulation (TMS) protocols were used to analyze resting motor thresholds (RMT) and intracortical inhibitory (short interval intracortical inhibition-SICI) and excitatory (intracortical facilitation-ICF) circuits' imbalance between the affected and nonaffected motor cortices. Results: We observed a significant increase in RMT and SICI in the affected motor cortex (p < 0.001), but not for ICF, compared to the contralateral unaffected side. Conclusion: This study extends current knowledge of functional weakness, arguing for a specific central nervous system abnormality which may be involved in the symptoms' pathophysiology.

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“…In addition, patients with functional weakness have shown a prolongation of the short-interval intracortical inhibition facilitation, which is a parameter of sensorimotor integration. 77 A SPECT study demonstrated that during vibratory stimulation, patients had reduced rCBF in the thalamus and basal ganglia contralateral to the paresis. Importantly, this abnormal pattern of activity normalised after clinical recovery suggesting that it might reflect a reversible impairment of sensorimotor function.…”

Section: Functional Neuroimaging Biomarkersmentioning

confidence: 99%

Biomarkers in functional movement disorders: a systematic review

Thomsen

Teodoro

Edwards

2020

J Neurol Neurosurg Psychiatry

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Functional movement disorders (FMD) are proposed to reflect a specific problem with voluntary control of movement, despite normal intent to move and an intact neural capacity for movement. In many cases, a positive diagnosis of FMD can be established on clinical grounds. However, the diagnosis remains challenging in certain scenarios, and there is a need for predictors of treatment response and long-term prognosis.In this context, we performed a systematic review of biomarkers in FMD. Eighty-six studies met our predefined criteria and were included.We found fairly reliable electroencephalography and electromyography-based diagnostic biomarkers for functional myoclonus and tremor. Promising biomarkers have also been described for functional paresis, gait and balance disorders. In contrast, there is still a lack of diagnostic biomarkers of functional dystonia and tics, where clinical diagnosis is often also more challenging. Importantly, many promising findings focus on pathophysiology and reflect group-level comparisons, but cannot differentiate on an individual basis. Some biomarkers also require access to time-consuming and resource-consuming techniques such as functional MRI.In conclusion, there are important gaps in diagnostic biomarkers in FMD in the areas of most clinical uncertainty. There is also is a lack of treatment response and prognostic biomarkers to aid in the selection of patients who would benefit from rehabilitation and other forms of treatment.

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Multimodal Brain Analysis of Functional Neurological Disorders: A Functional Stroke Mimic Case Series

Cited by 4 publications

References 9 publications

Pathophysiology and Treatment of Functional Paralysis: Insight from Transcranial Magnetic Stimulation

Pathophysiology and Treatment of Functional Paralysis: Insight from Transcranial Magnetic Stimulation

Cortical Inhibitory Imbalance in Functional Paralysis

Biomarkers in functional movement disorders: a systematic review

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