Advances in local field potential research in prolonged disorders of consciousness: a narrative review

Prolonged disorders of consciousness (pDOC)-including coma, vegetative state/unresponsive wakefulness syndrome (VS/UWS), and minimally conscious state (MCS)-remain diagnostically and therapeutically challenging. Even with validated instruments such as the Coma Recovery Scale-Revised (CRS-R), behavioral assessment yields misdiagnosis rates approaching 40%, as fluctuating arousal, motor impairment, and sedation can mask preserved cognition. Because the VS/UWS-MCS distinction directly shapes prognostic counseling, rehabilitation, and decisions about life-sustaining treatment, and because the circuit-level pathophysiology of pDOC is still incompletely mapped, objective physiology-based biomarkers are urgently needed to complement bedside examination. This narrative review, informed by a structured search of PubMed, Embase, MEDLINE, and Web of Science, focuses on studies directly reporting intracranial electrophysiology-particularly local field potential (LFP) recordings from the central thalamus-in patients with pDOC. Indirect evidence from anesthesia paradigms, animal models, and related neuromodulation settings is invoked only to clarify mechanism or methodology. We group current findings into four complementary signal domains: oscillatory activity (slow oscillations and burst suppression through theta, alpha, beta, and gamma rhythms); thalamocortical and corticostriatal functional connectivity; aperiodic/scale-free dynamics reflecting excitation-inhibition balance; and nonlinear complexity measures indexing information integration. Single-unit firing, cross-frequency coupling (CFC), and evoked or perturbational responses are considered alongside these. All four are interpreted within a unifying mesocircuit-and-criticality framework, in which impaired consciousness reflects reduced arousal gain, degraded thalamocortical integration, and departure from the critical dynamical regime sustaining conscious-capable dynamics. Intracranial LFP recordings thus offer a rare mechanistic window onto thalamocortical dysfunction in pDOC and may eventually inform patient stratification, target selection, and mechanism-guided neuromodulation. The evidence base remains limited; however, small samples, etiological heterogeneity, variable recording conditions, sparse direct human data, and a predominance of group- rather than individual-level analyses constrain current inference. Translation is further complicated by unresolved ethical issues around surrogate consent, equitable access, and disclosure of diagnostic uncertainty. Meaningful progress will depend less on technical novelty than on standardized protocols, multicenter validation, and rigorous ethical frameworks.