Hard of hearing have varying amounts of hearing loss but usually not enough to be considered deaf. Hearing impaired persons with partial loss of hearing may find that the quality of their hearing vary from day to day, or from one situation to another or not at all. They may also, to a greater or lesser extent, depend on both hearing-aids and lip-reading. They may perhaps not always be aware of it, but they do admit to it being important to see the speaker's face in conversation. Many people with hearing loss have better hearing in the lower frequency ranges (low tones), and cannot hear as well or at all in the higher frequencies. The speaker's accent; the topic under discussion, possibly with many unfamiliar words; the softness of his voice; possibly his having a speech impediment; a habit of holding a hand in front of his mouth or turning his face away at times: all these tendencies cause problems to the hard-of-hearing, especially when they have to rely on lip-reading. The rustling of papers and notebook pages being turned are precisely the noises that will be the first thing hearing-aids pick up. Noisy situations are especially difficult, because hearing loss affects not only the ability to hear sounds, but also the ability to localize and filter out background noise. A rule of thumb is that bright lighting is to the hearing-impaired what noise is to the hearing; a source of distraction.