Listening Effort and Speech Perception Performance Using Different Facemasks.

PURPOSE: The aim of this study was to assess the effect of eight different facemasks on speech perception and listening effort in listeners with normal hearing (NH) and hearing loss by manipulating both mask type and background noise levels. METHOD: Forty adults listened to Quick Speech-in-Noise Test sentences recorded by a female talker through eight different facemasks including a baseline condition with no mask. Listeners were tested in the sound field positioned 6 ft from the loudspeaker. Signal-to-noise ratio (SNR) loss and listening effort were measured. RESULTS: Listeners with NH exhibited a mild SNR loss, whereas those with hearing loss experienced a moderate SNR loss. Scores for the mild hearing loss group were significantly poorer (higher) than those with slight hearing loss. Speech perception performance was best in the no mask, KN95, and surgical mask conditions and poorest in the cloth mask and cloth mask plus face shield conditions for all groups. As listening effort decreased, speech perception increased for all groups. CONCLUSIONS: The impact of different types of facemasks on speech perception in noise was demonstrated in this study indicating that as the SNR was reduced, listening effort increased and speech perception performance decreased for listeners with NH and slight/mild hearing loss. No mask, KN95, and surgical masks had the least impact on performance, whereas cloth masks posed a significant detriment to communication. If communication is to occur in a background of noise while wearing masks, a KN95 mask and an SNR of at least +15 dB is recommended regardless of hearing status.

Cochabamba: reconstrucción de una historia

Larson analiza el proceso de formación y evolución de una clase campesina étnicamente mestiza en los valles de Cochabamba, desde una perspectiva histórica de largo plazo. Para cumplir con su objetivo, la investigación cubre un espacio temporal que abarca las eras de la expansión de los Estados Inca y Español al Collasuyu y Alto Perú, respectivamente, y el período republicano de Bolivia.

participación indigena en los mercados surandinos: estrategias y reproducción social siglos XVI al XX

CIDASC: Trabajo que recoje una serie de ensayos y análisis sobre la participación indígenaen los mercados, incorporando perspectivas tanto de la investigación etnohistórica como de la historia económica reciente del sur de los andes, en particular de Bolivia. Este libro recoje la contribución de diversos investigadoresde América latina, Europa y los Estados Unidos, durante los últimos 6 años.

Explotacion agraria y resistencia campesina en Cochabamba

Contiene: Cambio agrario en una economia colonial: el caso de Cochabamba 1580-1800 - Hacendados y campesinos en Cochabamba en el siglo XVIII - Ritmos rurales y conflictos de clases durante el siglo XVIII en Cochabamba - El mercado coactivo y las bases de las rebeliones rurales del Alto Peru - Dimensiones historicas de la dinamica economica del campesinado contemporaneo en la region de Cochabamba.