Migraine Aura: This condition can cause transient numbness and tingling, often without headache, and may be accompanied by symptoms like brain fog and memory issues. The episodic nature of the symptoms fits with migraine aura, which can occur with or without a subsequent headache.

Multiple Sclerosis (MS): Early symptoms of MS can include numbness and tingling, which can be localized to one area of the body, such as the back of the head. Brain fog and memory problems are also common in MS.
Vitamin B12 Deficiency: A deficiency in vitamin B12 can lead to neurological symptoms including numbness and tingling, as well as cognitive difficulties like brain fog and memory issues.
Anxiety or Stress: High levels of anxiety or stress can lead to physical symptoms including numbness and tingling, often due to hyperventilation or muscle tension, and can also impair cognitive function.

Transient Ischemic Attack (TIA) or Stroke: Although less likely given the absence of other symptoms, it's crucial to consider TIA or stroke, especially if the numbness and tingling are sudden in onset. These conditions require immediate medical attention.
Brain Tumor: A tumor in the brain could cause localized numbness and tingling, along with cognitive symptoms. While rare, this diagnosis has significant implications and should not be overlooked.
Temporal Arteritis: This condition, more common in older adults, can cause neurological symptoms including numbness and tingling, and requires prompt treatment to prevent complications like vision loss.

Neurosyphilis: A rare condition that can cause a wide range of neurological symptoms, including numbness and tingling, and cognitive difficulties.
Lyme Disease: In its later stages, Lyme disease can cause neurological symptoms, including numbness and tingling, though this would typically be accompanied by other symptoms.
Sjögren's Syndrome: An autoimmune disorder that can cause neurological symptoms, including numbness and tingling, among its wide range of potential effects.