The National Academies of Sciences, Engineering, and Medicine will convene an ad hoc committee to conduct an overview of reviews evaluating the associations between selected military-related exposures for 1990-1991 Gulf War and Post-9/11 service members and the development of the named neurodegenerative conditions among veterans:

• Parkinson’s disease;
• Alzheimer’s disease and other forms of dementia;
• Primary lateral sclerosis;
• Myasthenia gravis;
• Peripheral neuropathy;
• Transverse myelitis;
• Neuromyelitis optica; and
• Inclusion body myositis.

The committee will identify and assess existing systematic reviews and high-quality evidence syntheses that examine associations between the following categories of exposures most commonly experienced in military settings and the specified neurodegenerative outcomes:

• Organophosphorus, organochlorine, pyrethroid, DEET, and carbamate pesticides;
• Jet fuels of JP-4, JP-5, JP-8, and Jet A, hydrazine, and diesel fuel;
• Trichloroethylene, toluene, chlorobenzene, tetrachloroethylene solvents
• Heavy metals of lead, arsenic, mercury, and cadmium;
• Per- and polyfluoroalkyl substances, specifically PFOS, PFOA, PFHxS, PFNA, HFPO-DA, and PFBS; and
• Particulate matter (2.5 μm).

The committee will:
1. Describe the strength, consistency, and gaps in the existing body of systematic reviews, including assessment of methods, populations studied, and exposure definitions.
2. Summarize the evidence for associations between each exposure category and specific neurodegenerative outcomes.
3. Identify research and data needs, including recommendations for future primary studies or systematic reviews.
The committee will not conduct new systematic reviews or primary analyses of individual-level data.