Could hospitalisation open a window of repair for the ageing brain?

An exemplary sequential structure (in silico → pilot → confirmatory) is provided, with explicit GO/NO-GO/PIVOT criteria, thereby enabling rational and economical decision-making before a costly trial is launched.

The hypothesis proposes an elegant and mechanistically plausible transposition of the developmental (paediatric) 'critical window' concept to the domain of geriatrics, drawing upon specific molecular mechanisms (perineuronal net sulfation, BDNF) and a precise chronology (≤14 days). This analogy, although risky, is heuristically powerful and opens a wholly novel therapeutic avenue, distinct from standard rehabilitation approaches that do not account for non-linear post-stress dynamics.

The hypothesis is judged to be mechanistically bold and proposes a clearly defined temporal window (≤14 days), which permits a sharp experimental refutation.

A clear and urgent addressable market: geriatric post-hospitalisation syndrome represents an annual cost of $26 billion in the USA (readmissions plus loss of autonomy). Payers (Medicare Advantage, ACOs) are funded to reduce 30-day readmissions and functional decline. A 14-day protocol is compatible with existing reimbursement cycles (bundled payments for hip fracture, stroke, heart failure).

An original mechanistic hypothesis is proposed, anchored in a precise temporal paradigm (window ≤14 days), which carves out a distinct research niche separate from standard geriatric trials, offering strong scientific differentiation for reviewers.