Table:
Bell's palsy

A person attempting to show his teeth and raise his eyebrows with Bell's palsy on his right side (left side of the image; notice how the forehead is not spared).
Specialty	Neurology, ENT
Symptoms	Inability to move the facial muscles on one side, change in taste, pain around the ear[1]
Usual onset	Over 48 hours[1]
Duration	<6 months[1]
Causes	Unknown[1]
Risk factors	Diabetes, recent upper respiratory tract infection[1]
Diagnostic method	Based on symptoms[1]
Differential diagnosis	Brain tumor, stroke, Ramsay Hunt syndrome, Lyme disease[2]
Treatment	Corticosteroids, eye drops, eyepatch[1][3]
Prognosis	Most recover completely[1]
Frequency	1–4 per 10,000 per year[2]

I need you to conduct the following task:
Given this table image, find all merged table cells and return merged regions with the JSON {'top-left':(R1, C1), 'bottom-right':(R2, C2)},  where (R1, C1) and (R2, C2) indicate the (row_id, column_id) of top-left and bottom-right cells in the merged regions, respectively. You should remember that row id and column id start from 1.

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