Epilepsia Open. 2023 Jul 12. doi: 10.1002/epi4.12790. Online ahead of print.
ABSTRACT
OBJECTIVE: Cortical stimulation is an important component of stereo-electroencephalography (SEEG). Despite this, there is currently no standardised approach and significant heterogeneity in the literature regarding cortical stimulation practices. Via an international survey of SEEG clinicians, we sought to examine the spectrum of cortical stimulation practices to reveal areas of consensus and variability.
METHODS: A 68-item questionnaire was developed to understand cortical stimulation practices including neurostimulation parameters, interpretation of epileptogenicity, functional and cognitive assessment and subsequent surgical decisions. Multiple recruitment pathways were pursued, with the questionnaire distributed directly to 183 clinicians.
RESULTS: Responses were received from 56 clinicians across 17 countries with experience ranging from 2 to 60 years (M=10.73, SD=9.44). Neurostimulation parameters varied considerably, with maximum current ranging from 3-10mA (M=5.33, SD=2.29) for 1Hz and 2-15mA (M=6.54, SD=3.68) for 50Hz stimulation. Charge density ranged from 8-200μC/cm2 , with up to 43% of responders utilising charge densities higher than recommended upper safety limits i.e.55μC/cm2 . North American responders reported statistically significant higher maximum current (p<0.001) for 1Hz stimulation and lower pulse width for 1Hz and 50Hz stimulation (p=0.008, p<0.001, respectively) compared to European responders. All clinicians evaluated language, speech, and motor function during cortical stimulation; in contrast, 42% assessed visuospatial or visual function, 29% memory, and 13% executive function. Striking differences were reported in approaches to assessment, classification of positive sites and surgical decisions guided by cortical stimulation. Patterns of consistency were observed for interpretation of the localising capacity of stimulated electroclinical seizures and auras, with habitual electroclinical seizures induced by 1Hz stimulation considered the most localising.
SIGNIFICANCE: SEEG cortical stimulation practices differed vastly across clinicians internationally, highlighting the need for consensus based clinical guidelines. In particular, an internationally standardised approach to assessment, classification, and functional prognostication will provide a common clinical and research framework for optimising outcomes for people with drug-resistant epilepsy.
PMID:37437189 | DOI:10.1002/epi4.12790
