Can semantic context information mask rollover in hearing-impaired listeners?

The main purpose of hearing aids is to improve speech audibility by providing level-dependent gain. At low levels, more audibility usually leads to better speech intelligibility. However, this is not necessarily the case at high levels, where increasing the presentation level can lead to poorer intelligibility, i.e., ‘rollover’. This rollover effect has been observed in both normal-hearing and hearing-impaired listeners.
While rollover typically first occurs at relatively high levels when speech is presented in quiet, it has also been observed at conversational levels under noisy conditions. Additionally, top-down processes, such as the use of semantic context information, have been found to mask rollover in normal-hearing listeners.
This study investigated the influence of semantic context information on rollover in hearing-impaired listeners. Speech intelligibility measurements were performed with three speech materials differing in terms of semantic context (monosyllabic words, context-free and context-rich sentences) at three speech levels (55, 65 and 75 dB SPL) with individually determined noise levels. To ensure audibility, a wearable hearing-aid simulator providing individual linear amplification was used.
It is expected that clear rollover will be found for the speech materials without semantic context but not for the context-rich sentences.