Transient Ischemic Attacks (TIAs): Given the patient's age and the nature of the episodes (preserved consciousness but inability to move or speak), TIAs are a strong consideration. These episodes could be indicative of temporary disruptions in blood supply to parts of the brain, leading to transient neurological deficits without loss of consciousness.

Seizures (specifically, focal seizures with impaired awareness): Although the patient reports preserved consciousness, the description could also fit complex partial seizures where the patient might appear to be conscious but is actually unresponsive and unable to interact with their environment.
Psychogenic Non-Epileptic Seizures (PNES): These are episodes that resemble epileptic seizures but are not caused by abnormal electrical activity in the brain. They can be triggered by psychological factors and might present with a variety of symptoms, including inability to move or speak.
Sleep Paralysis: This condition occurs when the body is in a state of rapid eye movement (REM) sleep, but the brain is partially awake, leading to an inability to move or speak. However, it typically occurs at night, which might not fully align with the patient's daytime episodes.

Stroke: Although the episodes are transient and the patient recovers, it's crucial not to miss the possibility of a stroke, especially given the patient's age. Prompt recognition and treatment of stroke are critical for preventing long-term damage.
Cardiac Arrhythmias: Certain arrhythmias can lead to transient cerebral hypoperfusion, resulting in episodes of neurological dysfunction. Conditions like atrial fibrillation or other arrhythmias could potentially cause these symptoms.
Hypoglycemia: Low blood sugar can cause a variety of neurological symptoms, including confusion, weakness, and even transient paralysis. It's a condition that requires immediate attention to prevent serious complications.

Narcolepsy with Cataplexy: This condition involves sudden, brief episodes of muscle weakness often triggered by strong emotions, which could potentially be mistaken for "blackouts." However, it's typically associated with other symptoms like excessive daytime sleepiness.
Mitochondrial Myopathies: These are a group of disorders caused by mutations in the mitochondria, affecting muscle and nerve cells. Some forms can present with episodes of weakness or paralysis, but they are relatively rare and would likely be accompanied by other systemic symptoms.
Periodic Paralysis: A rare genetic disorder characterized by episodes of muscle weakness or paralysis, often triggered by factors like rest or meals after exercise. It's less likely given the patient's age at presentation but should be considered in the differential diagnosis.