Functional Seizures: Diagnostic Technique Inventory

Expanded pages: typical-event video-EEG, smartphone-video assessment and whole-event semiology. Individual methods not fully appraised there remain for staged review.

Original twenty entries

Typical-event video-EEG

A specialist interprets a familiar event’s video together with its EEG. A compatible event without the epileptic activity expected for that event can support documented functional seizures. Some epileptic seizures lack a clear scalp EEG correlate; a normal routine EEG is insufficient. [1][3]

Smartphone-video assessment

With consent, a safely recorded spontaneous event can supplement history. A prospective masked study found added diagnostic value when experts reviewed recordings. Missing onset, poor visibility and unfamiliar events limit interpretation; recording must never delay first aid. [4]

Ictal eye closure

Sustained or forceful eye closure during an event can support functional seizures in the appropriate semiological pattern. Primary studies and pooled evidence exist, but eye closure can also occur in epilepsy. Observation on video is more informative than recollection alone. [5][6]

Asynchronous limb movements

Out-of-step movements of the limbs during a convulsive-appearing event may support functional seizures. This is a studied semiological feature, not an absolute discriminator; frontal and hypermotor epileptic events can overlap. [6][7]

Fluctuating course

Repeated waxing and waning or pauses during an event can support a functional pattern. A blinded video study evaluated this feature alongside other movements. It must be assessed as part of the entire event, not from an isolated pause. [8]

Event duration

Clinicians time the event and its phases. Longer duration may shift diagnostic probability, but duration alone cannot identify the cause. An undiagnosed prolonged convulsive event still requires appropriate emergency assessment rather than a timing-based FND assumption. [9]

Side-to-side head movement

Repetitive head shaking is a descriptive clue studied in video-EEG cohorts. It occurs in both functional and epileptic seizures and has limited standalone value. It should never become a visual shortcut to diagnosis. [6][8]

Pelvic thrusting

Pelvic movements are recorded as part of the event sequence. Direct comparative research found overlap with epileptic seizures, including frontal presentations. This sign alone is insufficient and has no bearing on the person’s intent or sexual behaviour. [6][10]

Back arching

The examiner records trunk extension or arching without trying to reproduce or restrain it. Comparative video research did not establish it as a reliable independent discriminator. Arching cannot establish FND or rule out epilepsy. [8]

Ictal responsiveness

A clinician may assess whether a simple, non-distressing instruction is understood during an event. Preserved or changing responses can help characterize the episode, but some epileptic seizures preserve awareness. No response does not establish epilepsy either. [3][11]

Recall of the event

The clinician asks afterward what was heard or remembered. Recall can contribute to the event formulation alongside observed behaviour and EEG. It is not a test of honesty, and preserved memory alone cannot distinguish all seizure types. [3][6]

Postictal breathing and recovery

Breathing pattern, time to ordinary interaction and confusion after the event provide additional context. Comparative studies describe differences after convulsive events, but drugs, hypoxia, injury and seizure type affect recovery. These observations are not standalone tests. [12]

Ictal crying or weeping

Crying during an event has been reported in comparative research and may contribute to a pattern. It is not exclusive to functional seizures, does not reveal the cause of the event and does not mean the episode is an emotional choice. [6][13]

Combined semiology tools

Structured scores combine several observed features rather than relying on one movement. Published development and validation work exists, but accuracy depends on the setting, reference diagnosis and population. These tools support trained assessment and do not replace video-EEG when indicated. [14]

ILAE diagnostic-certainty framework

History, witnessed events, specialist observation and EEG evidence support different levels of diagnostic certainty. These are consensus criteria, not several interchangeable positive tests. Record which level is supported and whether all habitual event types have been assessed. [3]

Hand/arm-drop avoidance during unresponsiveness

A hand changing course during release has been described in apparent unresponsiveness, including the context of a seizure-like event. Evidence is descriptive, not a validated standalone seizure test. Never deliberately drop a limb toward the face; avoidance does not prove FND or conscious control. [15][16]

Modified hand-drop and eyelid observations

Specialist descriptions include a modified hand-drop observation and assessment of eyelid opening intended to avoid injury. These may contribute to assessment of functional unresponsiveness, which is not identical to every functional seizure. Robust diagnostic-accuracy validation is lacking. [16]

Suggestion and induction protocols

Some services use consented activation or suggestion during monitoring to capture a typical event. An induced event must be verified as habitual and interpreted with EEG and clinical context. Inducibility alone is not diagnostic; deception, painful stimuli and unsafe provocation are inappropriate. [1][17]

Prolactin, lactate and creatine kinase

Selected post-event blood tests may help answer a differential question, but timing, seizure type and other causes limit them. Neither normal nor abnormal values establish functional seizures. These are ancillary investigations, not positive FND signs. [1][18]

Tilt testing for apparent blackouts

When the phenotype suggests syncope or apparent unresponsiveness, specialist tilt assessment with blood pressure, heart rate and sometimes EEG can distinguish mechanisms. Evidence for psychogenic pseudosyncope does not automatically apply to convulsive functional seizures; the diagnoses can coexist. [19]

Research and Sources

Original citation numbers 1–19 are retained. The AAN citation’s author list and journal details have been corrected against its primary record. Expanded pages record newly reviewed evidence and access limits; inherited sources are not all freshly reviewed in full.

Citation	Figure	Full citation
[1]	—	Tolchin B, Goldstein LH, Reuber M, et al. Management of functional seizures practice guideline executive summary: report of the AAN Guidelines Subcommittee. Neurology. 2026;106(1):e214466. FND-CIT-0010. https://doi.org/10.1212/WNL.0000000000214466 AAN clinician summary.
[2]	—	Bennett K, Diamond C, Hoeritzauer I, Gardiner P, McWhirter L, Carson A, Stone J. A practical review of functional neurological disorder (FND) for the general physician. Clinical Medicine. 2021;21(1):28–36. FND-CIT-0001. https://doi.org/10.7861/clinmed.2020-0987
[3]	—	LaFrance WC, Baker GA, Duncan R, et al. Minimum requirements for the diagnosis of psychogenic nonepileptic seizures: a staged approach: a report from the International League Against Epilepsy Nonepileptic Seizures Task Force. Epilepsia. 2013;54(11):2005-2018. DOI. PMID: 24111933. FND-CIT-0146.
[4]	—	Tatum WO, Hirsch LJ, Gelfand MA, et al. Assessment of the Predictive Value of Outpatient Smartphone Videos for Diagnosis of Epileptic Seizures. JAMA neurology. 2020;77(5):593-600. DOI. PMID: 31961382. FND-CIT-0168.
[5]	—	Chung SS, Gerber P, Kirlin KA. Ictal eye closure is a reliable indicator for psychogenic nonepileptic seizures. Neurology. 2006;66(11):1730-1731. DOI. PMID: 16769949. FND-CIT-0139.
[6]	—	Muthusamy S, Seneviratne U, Ding C, Phan TG. Using Semiology to Classify Epileptic Seizures vs Psychogenic Nonepileptic Seizures: A Meta-analysis. Neurology. Clinical practice. 2022;12(3):234-247. DOI. PMID: 35747545. FND-CIT-0165.
[7]	—	Gates JR, Ramani V, Whalen S, Loewenson R. Ictal characteristics of pseudoseizures. Archives of neurology. 1985;42(12):1183-1187. DOI. PMID: 3933461. FND-CIT-0144.
[8]	—	Duncan AJ, Peric I, Boston R, Seneviratne U. Predictive semiology of psychogenic non-epileptic seizures in an epilepsy monitoring unit. Journal of neurology. 2022;269(4):2172-2178. DOI. PMID: 34550469. FND-CIT-0161.
[9]	—	Seneviratne U, Minato E, Paul E. How reliable is ictal duration to differentiate psychogenic nonepileptic seizures from epileptic seizures? Epilepsy & behavior : E&B. 2017;66:127-131. DOI. PMID: 28039841. FND-CIT-0133.
[10]	—	Geyer JD, Payne TA, Drury I. The value of pelvic thrusting in the diagnosis of seizures and pseudoseizures. Neurology. 2000;54(1):227-229. DOI. PMID: 10636155. FND-CIT-0157.
[11]	—	Wardrope A, Wong S, McLaughlan J, et al. Peri-ictal responsiveness to the social environment is greater in psychogenic nonepileptic than epileptic seizures. Epilepsia. 2020;61(4):758-765. DOI. PMID: 32154929. FND-CIT-0163.
[12]	—	Azar NJ, Tayah TF, Wang L, et al. Postictal breathing pattern distinguishes epileptic from nonepileptic convulsive seizures. Epilepsia. 2008;49(1):132-137. DOI. PMID: 17651411. FND-CIT-0159.
[13]	—	Walczak TS, Bogolioubov A. Weeping during psychogenic nonepileptic seizures. Epilepsia. 1996;37(2):208-210. DOI. PMID: 8635432. FND-CIT-0184.
[14]	—	De Paola L, Terra VC, Silvado CE, et al. Improving first responders’ psychogenic nonepileptic seizures diagnosis accuracy: Development and validation of a 6-item bedside diagnostic tool. Epilepsy & behavior : E&B. 2016;54:40-46. DOI. PMID: 26645799. FND-CIT-0167.
[15]	—	Marcus H, Aldam P, Lennox G, Laing R. Medically unexplained neurological symptoms. JRSM short reports. 2010;1(3):25. DOI. PMID: 21103117. FND-CIT-0153.
[16]	—	Bacchi S, Slee M. Physical examination in functional unresponsiveness. Practical neurology. 2023;23(1):54-56. DOI. PMID: 36717206. FND-CIT-0119.
[17]	—	Popkirov S, Grönheit W, Wellmer J. A systematic review of suggestive seizure induction for the diagnosis of psychogenic nonepileptic seizures. Seizure. 2015;31:124-132. DOI. PMID: 26362389. FND-CIT-0148.
[18]	—	Chen DK, So YT, Fisher RS, Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Use of serum prolactin in diagnosing epileptic seizures: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 2005;65(5):668-675. DOI. PMID: 16157897. FND-CIT-0123.
[19]	—	Tannemaat MR, van Niekerk J, Reijntjes RH, et al. The semiology of tilt-induced psychogenic pseudosyncope. Neurology. 2013;81(8):752-758. DOI. PMID: 23873974. FND-CIT-0174.