Table 1. Study definitions for different disability types and their corresponding survey questions.

Disability type	Survey question	Definition
Visual	Do you or your family members have visual problems?	Visual disability refers to poor vision or constriction of the visual field in both eyes from any cause and is not correctable. It consists of two categories: blindness and weak vision.
Hearing and speech	Do you or your family members have hearing or speech problems?	Hearing disability refers to permanent hearing loss of varying degrees from any cause or the inability to hear at all or to hear clearly any nearby sound or voice. These deficits affect daily life and social activities.
		Speech disability refers to any type of language disorder. Because successful treatment takes more than 1 year and the disability is generally present for more than 2 years, the patient cannot take part in normal language exchanges, which undermines his or her daily life and participation in social activities.
Physical	Do you or your family members have any difficulty walking, standing, squatting, climbing the stairs, grasping, washing and rinsing, or dressing?	Physical disability refers to a loss of motor function of varying degrees or to limitations in movements or activities resulting from deformed limbs or body paralysis (palsy) or from deformity caused by damage to the structure or function of those body parts involved in mobility.
Intellectual	Do you or your family members have any difficulty studying?	Intellectual disability refers to lower than normal intellectual ability and is accompanied by adaptive behaviour disorders. This kind of disability results from impairment of the structure and functions of the nervous system, limits individual activity and participation, and requires all-round, extensive, limited, or intermittent support.
Mental	Are you or your family members forgetful? Or do you have difficulty concentrating? Or can you not control your moods? Or do you have strange behaviour that is out of the ordinary? Or are you addicted to alcohol or drugs?	Mental disability refers to psychiatric disorders lasting more than 1 year that manifest as cognitive, affective, and behaviour disorders affecting the daily life and social participation of the patient.