double boiler function

[bark]

Здравствуйте!
И снова фрагмент из книги про заикание:
"Defining stuttering as a fluency
problem ...ignores the person: it ignores his feelings about himself, it ignores the
significance of stuttering in his life; it ignores ...the ‘double boiler’ function of
maintenance of the handicap in many cases; it ignores the principle that just
because an individual stutters, that is necessarily the chief problem with which a
clinician need be concerned."

Как образно перевести на русский это "double boiler function"? Функция буфера?

Заранее спасибо!