Excitation-inhibition imbalance as a common thread linking early Alzheimer's disease with temporal lobe epilepsy.

Growing evidence suggests that network hyperexcitability is a pivotal yet under-recognized pathology linking early Alzheimer's disease (AD) with mesial Temporal Lobe Epilepsy (mTLE). This narrative review synthesises pre-clinical and clinical data showing how disruption of excitation-inhibition balance, driven chiefly by the loss or dysfunction of parvalbumin- and somatostatin-positive GABAergic interneurons (INs), emerges early in AD and fosters subclinical epileptiform activity that hastens cognitive decline. We integrate findings that degeneration of Ventral Tegmental Area dopaminergic projections further destabilises hippocampal circuits by diminishing D2-mediated restraint of pyramidal firing and attenuating anti-inflammatory signalling. Convergent co-pathologies, soluble amyloid-β oligomers, tau mis-localisation, glutamate-dependent excitotoxicity and glia-mediated neuroinflammation amplify IN vulnerability and form a self-reinforcing loop of hyperexcitability, plasticity failure and neurodegeneration. Parallels with mTLE, where similar IN and dopaminergic deficits precipitate seizures, provide a mechanistic framework for interpreting EEG abnormalities and seizure susceptibility in prodromal AD. We critically appraise the therapeutic potential of interventions that restore excitation-inhibition balance or neuromodulatory tone, including interneuron-sparing agents, selective D2-like agonists, transcranial stimulation and anti-inflammatory or anti-excitotoxic strategies. By viewing early AD through a circuit-centric lens that bridges neurodegeneration and Epilepsy, we highlight testable biomarkers, propose stage-specific targets and argue that timely suppression of hyperexcitability could slow progression far upstream of irreversible neuronal loss. Such precision approaches may redefine disease modification by stabilizing vulnerable hippocampal networks before cognitive function is irrevocably compromised.