Table:
Concussion
Other names	Mild brain injury, mild traumatic brain injury (mTBI), mild head injury (MHI), minor head trauma

Acceleration (g-forces) can exert rotational forces in the brain, especially the midbrain and diencephalon.
Specialty	Emergency medicine, neurology
Symptoms	Headache, trouble with thinking, memory or concentration, nausea, blurry vision, sleep disturbances, mood changes[1]
Duration	Up to 4 weeks[2]
Causes	Motor vehicle collisions, falls, sports injuries, bicycle accidents[3][4]
Risk factors	Drinking alcohol[5]
Diagnostic method	Based on symptoms[6]
Prevention	Helmets when bicycling or motorbiking[3]
Treatment	Physical and cognitive rest for a day or two with a gradual return to activities[7][2]
Medication	Paracetamol (acetaminophen), NSAIDs[2]
Frequency	6 per 1,000 people a year[3]

In this table image, are there any merged cells? If so, describe their locations using the JSON format {'top-left':(X, Y), 'bottom-right':(Z, W)}, where (X, Y) and (Z, W) indicate the (row_id, column_id) of top-left and bottom-right cells in the merged regions, respectively. Note that the X, Y, Z, W all start from 1.

The merged cell area is: {'top-left':(1, 1), 'bottom-right':(1, 2)}.