Final answer:
The condition described, associated with amyloid-β deposits and tau protein tangles, is Alzheimer's disease, a neurodegenerative disorder leading to progressive dementia.
Step-by-step explanation:
The condition described in the question, characterized by both extracellular deposits of amyloid-β, or Aβ, and intracellular tangles of a protein called tau, is Alzheimer's disease. Alzheimer's disease is a neurodegenerative disorder marked by progressive neuronal death leading to memory loss and dementia. One of the hallmarks of Alzheimer's is the presence of neurofibrillary tangles composed of hyperphosphorylated tau protein within neurons and plaques primarily consisting of extracellular accumulations of beta-amyloid peptide fragments. These pathological features contribute to the impairment of synaptic functions, neuron communication, and brain atrophy, especially in the hippocampus which is critical to memory formation. Unlike Parkinson's disease, which is associated with protein alpha-synuclein, Alzheimer's disease is categorized as a proteopathy due to the abnormal behavior of tau and amyloid proteins that become toxic.