Definition of key concepts.

To clarify the conceptual framework of this review, the following key terms are defined:

Cognitive resilience refers to the ability to maintain or recover cognitive function despite exposure to physiological, pathological, or operational stressors, enabling adaptation and optimal performance under adverse conditions [9,10].

Nutritional strategies:

Structured dietary interventions designed to support and monitor the metabolic and neurocognitive status of military personnel by adjusting macronutrients, micronutrients, and fluid intake according to operational demands and environmental stressors [3,8].

Smart technologies are advanced devices and algorithms (e.g., biosensors, artificial intelligence, predictive analytics) that enable real-time monitoring of physiological and cognitive parameters relevant to nutritional status and cognitive resilience in extreme operational environments [2,3,8].

Extreme operational environment – Military conditions characterized by exposure to extreme temperatures, intense physical exertion, sleep deprivation, and limited access to nutritional resources [11,12].

Rationale.

Although specialized literature includes studies on military nutrition [13–15], cognitive performance in extreme environments, and the use of smart technologies in nutrition [16,17], there is no systematic analysis that integrates these dimensions into an operationally applicable model. Existing studies either examined the impact of nutrition on cognitive performance or the role of emerging technologies in monitoring nutritional status, but they did not explore the interaction between these variables in a military context. This lack of integration makes it difficult to develop evidence-based interventions that support both cognitive resilience and rapid decision making in extreme operational environments. A scoping review is necessary to synthesize existing literature, identify research gaps, and establish a foundation for more in-depth future studies.

Preliminary search and justification for a scoping review.

A preliminary search in PubMed, Cochrane Database of Systematic Reviews, and JBI Evidence Synthesis did not identify any systematic or scoping reviews that comprehensively investigated the integrated relationship between nutrition, smart technologies, and cognitive resilience in extreme operational contexts. Existing studies address these elements separately, either by analyzing the impact of nutrition on cognitive performance or by examining the use of emerging technologies for monitoring nutritional status.

This scoping review is justified, as it provides the first systematic synthesis of the literature on this topic, mapping current trends, research gaps, and future opportunities for investigation.

Objective.

This scoping review aims to map and analyze the scientific literature on nutritional strategies and smart technologies applicable to monitoring and supporting the cognitive resilience of military personnel deployed in extreme operational environments, identifying current trends, research gaps, and opportunities for practical implementation.

Review question

This scoping review will aim to answer the following questions using the PCC framework (Table 1):

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 1. Research questions formulated according to the PCC (Population, Concept, Context) framework.

https://doi.org/10.1371/journal.pone.0327649.t001

The scoping review will address these questions without testing a priori hypotheses; the goal is to comprehensively map the evidence base and identify knowledge gaps.

Inclusion criteria

Types of sources

This scoping review will include primary studies (randomized controlled trials, cohort studies, case-control studies, cross-sectional studies, and observational studies), qualitative studies (phenomenology, ethnography, grounded theory), and mixed-methods studies. Additionally, systematic and scoping reviews relevant to the topic will be included, along with grey literature, technical reports, military guidelines, and government documents related to nutrition and smart technologies in extreme military contexts.

Search strategy

The search strategy included both published sources and grey literature, following a three-stage approach:

Stage 1: An initial exploratory search of MEDLINE (PubMed) was conducted to identify relevant keywords and optimize the query strategy.

Stage 2: A comprehensive search of major databases, including PubMed/MEDLINE, Web of Science, Scopus, and IEEE Xplore, using keywords and indexed terms adapted to each database.

Stage 3: A grey literature review incorporating sources such as CyberLeninka, eLIBRARY.ru, and relevant government reports (NATO, WHO, DARPA) to complement the academic literature.

The full list of databases and an example PubMed query will be included in Appendix I. The search strategies for the other databases will be documented and reported in the final publication.

Study selection

All identified citations were imported and managed using Zotero [6.0.37] (Corporation for Digital Scholarship, VA, USA), with duplicates removed both automatically and manually. The screening process was conducted in two stages by two independent reviewers using Rayyan software. In the first stage, titles and abstracts were screened based on inclusion/exclusion criteria. In the second stage, full-text reviews were conducted for all relevant articles. Any discrepancies between the reviewers were resolved through discussion or, if necessary, by involving a third reviewer.

The study selection process will be documented using the PRISMA Flow Diagram, providing a transparent overview of the number of records identified, screened, included, and excluded at each stage [19–21]. Reasons for study exclusion at the full-text level will be documented in an appendix to enhance transparency.

Data extraction

Data were extracted using a standardized extraction tool developed in accordance with the JBI Manual for Evidence Synthesis [18]. The extracted variables will include the investigated population, referring to the categories of military personnel analyzed in the studies; documented nutritional strategies that describe the dietary interventions used to support cognitive resilience in military personnel; utilized smart and emerging technologies, including devices and technological solutions applied in operational nutrition; and the operational context, detailing the extreme environments and conditions in which these strategies are implemented. Additionally, the year of publication and any references to military or institutional nutritional standards in place at the time of the study will be extracted, to allow interpretation of the interventions within their historical and regulatory context.

Furthermore, the data extraction process will account for the operational profile of the military personnel included in each study, such as the type of mission (e.g., long-duration, low-intensity vs. short-duration, high-risk missions) and the specific military specialization (e.g., combat troops, special forces, logistics, aviation). This distinction is critical for contextualizing nutritional strategies and interpreting the applicability and relevance of monitoring technologies, as cognitive and physiological demands vary significantly across operational roles.

To enhance the relevance and applicability of the findings, studies will be examined for the technical specifications and validation criteria of the monitoring technologies used (e.g., accuracy, reliability under field conditions, and level of invasiveness). Where available, information regarding the type of biomarkers assessed (e.g., physiological, cognitive, metabolic) and the integration of real-time data with behavioral or cognitive outcomes will be extracted and reported. This will support a more comprehensive analysis of how smart technologies contribute to the monitoring of nutritional interventions in operational settings.

Data extraction will be conducted independently by two reviewers and any discrepancies will be resolved by consensus. A draft version of the extraction tool was piloted and adjusted throughout the study to ensure reliability.

Data analysis and presentation

Data will be synthesised narratively and in tabular form, following the PCC framework (Population, Concept, Context). All exploratory analyses, such as thematic mapping or subgroup comparisons (e.g., by service branch or environment), will be clearly labelled as exploratory. Any deviations from the planned methods will be recorded in a protocol deviation log and reported in the final manuscript.

Results will be presented as descriptive summaries supported by comparative tables and graphical visualisations, including thematic maps and diagrams that illustrate the geographic and temporal distribution of studies. A descriptive analysis of key findings will highlight current trends and remaining knowledge gaps in the literature.