Hand posture as localizing sign in adult focal epileptic seizures

Abstract

Objective: The aim of this study was to identify specific ictal hand postures (HPs) as localizing signs of the epileptogenic zone (EZ) in patients with frontal or temporal lobe epilepsy. Methods: In this study, we retrospectively analyzed ictal semiology of 489 temporal lobe or frontal lobe seizures recorded over a 6-year period at the Seizure Disorder Center at University of California, Los Angeles in the USA (45 patients) or at the C. Munari Epilepsy Surgery Center at Niguarda Hospital in Milan, Italy (34 patients). Our criterion for EZ localization was at least 2 years of seizure freedom after surgery. We analyzed presence and latency of ictal HP. We then examined whether specific initial HPs are predictive for EZ localization. Results: We found that ictal HPs were present in 72.5% of patients with frontal and 54.5% of patients with temporal lobe seizures. We divided HPs into 6 classes depending on the reciprocal position of the fingers ("fist," "cup," "politician's fist," "pincer," "extended hand," "pointing"). We found a striking correlation between EZ localization and ictal HP. In particular, fist and pointing HPs are strongly predictive of frontal lobe EZ; cup, politician's fist, and pincer are strongly predictive of temporal lobe EZ. Interpretation: Our study offers simple ictal signs that appear to clarify differential diagnosis of temporal versus frontal lobe EZ localization. These results are meant to be used as a novel complementary tool during presurgical evaluation for epilepsy. At the same time, they give us important insight into the neurophysiology of hand movements.

Ictal hand signs: Minimal previous attention to these diagnostic indicators

“…Ictal hand signs were found in 54.5% of patients with temporal lobe seizures and 72.5% of those with frontal epilepsies by Ferando et al [13]. The signs identified were cup, fist, pincer, politician's fist, index pointer, and extended hand, which corresponded to some of the signs observed in this study as shown in .…”

“…1, including their lateralization and localization values. The predominant lateralization and localization information of ictal hand signs has been presented in various studies [11,13,14,16]. Our video EEG monitoring analysis of 145 patients revealed six patients with ictal fist, six with ictal hand extension, five with ictal cup, three with RINCH, two with ictal thumbup, two with ictal pincer, and one each with ictal index pointers.…”

“…With regard to localization, different ictal hand postures (thumb abduction, wrist flexion, fist closure, finger hyperextension) were first classified in the temporal lobe by Holl et al [11]. Index finger pointing was subsequently described by Siegel and Tantum [12], and the ictal signs "politician's fist" and "pincer" were added by Ferando et al [13]. Ictal hand posture signs include elementary movement patterns with persistent tense muscle contractions that last for several seconds.…”

Thumb-up sign: Characterization of an undescribed seizure semiologic sign

“…Hand postures have been associated to focal onset seizures, particularly frontal and temporal onset [2]. Specifically, cup, politician's fist (thumb adjacent to index finger, not abducted as in thumb-up sign) and pincer posture predict temporal lobe localization, whereas fist (thumb opposite to other fingers) and pointing postures predict frontal lobe localization [2].…”

Index finger pointing posture in a patient with drug-induced foot tremor

“…Index-finger pointing posture is an unusual neurological manifestation commonly observed in patients with craniocervical dystonia, Parkinson’s disease, essential tremor, and epilepsy [1] , [2] . The prevalence of index-finger pointing posture in diverse neurological disorders remains unclear.…”