Fuzzy Pain Assessment in Musculoskeletal Disorder - Fuzziness and Medicine - page 355

equivalent in structure to Fuzzy Qualitative Pain Scale. Each of the input and out-
put universes of discourse can, thus, adopt the same number of partitions. The set
of linguistic terms and their associated membership functions are distributed in the
universe of discourse for the range of motion for shoulder flexion as X 1

=[ , ]

,
while the universe of discourse for the range of motion for shoulder extension is
X 2 =[

0 220

0 , 55 ] , and the quantification of pain (severity of disorder) is Y =[ 0 , 10 ] .

Fig. 24.4 Range of Motion for shoulder flexion and shoulder extension (adapted from [9])

Mamdani inference method is employed to represent the heuristic knowledge to
build the fuzzy IF-THEN rule base:

R 1 :IF Flexion is No AND Extension is No

THEN Pain / Disorder is Maximum

R 2 :IF Flexion is No AND Extension is Light

THEN Pain / Disorder is Maximum

...

R 24 :IF Flexion is Maximum AND Extension is Intense

THEN Pain / Disorder is Intense

R 25 :IF Flexion is Maximum AND Extension is Light

.
(24.2)
The linguistic terms part the input universes of discourse, angle of flexion , X 1 =
θ flexion ,and angle of extension , X 2 = θ ext ension , respectively, such that for M flexion

THEN Pain / Disorder is Normal

j