A demonstrative adjective does what an adjective usually does. It assigns a characteristic to a noun. A demonstrative pronoun doesn't assign a characteristic to a noun, it substitutes it. If we want to be concise, what we actually don't want, we must say, that the term demonstrative pronoun is wrong because a pronoun substitutes something, but a demonstrative adjective subsitutes nothing, it just describes something.
In Italian there are two demonstrative pronouns, questo and quello. Questo describes a temporal or local closeness to the speaker, quello describes temporal or local distance to the speaker. In relationship to a period of time questo is used if there is a close relationship to the present of the speaker (in questi tempi no si sa più che fare / nowadays one doesn't know what to do) otherwise quello / quei is to be used (a quei tempi tutto era meglio / in those times everything was better).