Multiple Sclerosis (MS): Although MS is more common in younger populations, it can present at any age, including in the elderly. The presentation of grey and white matter demyelination is consistent with MS, especially if there's a history of relapsing-remitting neurological symptoms.

Small Vessel Disease: This condition is common in the elderly and can cause white matter changes due to chronic small vessel ischemia. While it primarily affects white matter, there can be associated grey matter changes due to secondary degeneration.
Normal Pressure Hydrocephalus (NPH): NPH can cause gait disturbances, dementia, and urinary incontinence, with imaging showing ventriculomegaly and sometimes periventricular white matter changes. Grey matter can be indirectly affected due to the hydrocephalus.
Vitamin B12 Deficiency: This deficiency can cause subacute combined degeneration of the spinal cord but also affects the brain, leading to white matter changes and, less commonly, grey matter involvement.

Central Nervous System Lymphoma: Although rare, CNS lymphoma can present with rapidly progressive neurological decline and imaging showing lesions in both grey and white matter. It's crucial to consider this diagnosis due to its aggressive nature and need for prompt treatment.
Progressive Multifocal Leukoencephalopathy (PML): PML is a rare and often fatal viral disease caused by the JC virus that affects the white matter of the brain but can also involve grey matter. It typically occurs in immunocompromised individuals.
CNS Vasculitis: This condition can cause a wide range of neurological symptoms depending on the vessels affected and can involve both grey and white matter. It's essential to consider due to its potential for severe consequences if left untreated.

Leukodystrophies: These are a group of rare, genetic disorders characterized by the progressive degeneration of the white matter of the brain. Some forms can present later in life and affect both white and grey matter.
Mitochondrial Encephalomyopathies: These disorders affect the mitochondria and can cause a variety of neurological symptoms, including those related to grey and white matter disease. They are rare and often have a complex presentation.
Inherited Prion Diseases: Such as Creutzfeldt-Jakob disease, which can cause rapidly progressive dementia and neurological decline, with imaging showing grey matter changes. While rare, they are important to consider due to their distinctive clinical course and lack of treatment.