Final answer:
Matilda's condition would be classified under parasomnias, which are unwanted motor behaviors during sleep such as night terrors, sleepwalking, and sleep-related eating disorders.
Step-by-step explanation:
Matilda suffers from a sleep-related eating disorder, which would classify her as suffering from a class of sleep disorder known as parasomnias. This category includes a variety of unwanted motor behaviors or experiences throughout the sleep cycle, such as REM sleep behavior disorder (RBD), sleepwalking, restless leg syndrome, and night terrors. Sleep-related eating disorders involve involuntary eating while in a state of sleep, often leading to weight gain and health issues due to uncontrolled eating at night. It is a complex disorder at the crossroads of sleep disorders and eating disorders.