Table 1.
Instrument setting and location in the reviewed articles.
| Author (Year) | Sensors | Location |
|---|---|---|
| Afkari [30] | Miniature ACC (NM) | Level of thyroid cartilage |
| sEMG (NM) | Level of cricopharyngeus muscle | |
| Omnidirectional electret MIC (NM) | Level of cricoid cartilage | |
| Amft and Troster [31] | sEMG (Nexus-10, MindMedia) | Collar at infra-hyoid throat region |
| Stethoscope MIC (ECM-C115, Sony) | Collar below hyoid | |
| Bi et al. [32] | Throat MIC [NM] | Over neck close to the jaw |
| Fontana et al. [33] | Condenser MIC (CZN-15E) | thyroid cartilage level, one side of the neck |
| Piezoelectric MIC (IASUS NT, IASUS Concept Ltd.) | Over laryngopharynx | |
| Fukuike et al. [34] | Condenser MIC (WM-61A, Panasonic, Osaka, Japan) | Fixed on a silicone tube and placed inside the left nostril |
| Laryngeal MIC (SH-12iK, Nanzu, Shizuoka, Japan) | Over anterior larynx | |
| Kurihara et al. [35] | Bi-directional electret condenser MIC (EM114, Primo Co., Ltd.) | MIC attached to air tube hung over neck with anterior opening |
| Lee et al. [36] | Dual axis ACC (ADXL322) | Below thyroid cartilage aligned in anterior-posterior and superior-inferior axes |
| Submental mechanomyography (developed by Silva and Chau [42]) | On the geniohyoid | |
| Pressure Transducer (PTAFLITE, Glass Technologies) | At nasal cannula | |
| Makeyev et al. [37] | Throat microphone (IASUS NT, IASUS Concept Ltd.) * | Over laryngopharynx |
| Sazonov et al. [38] | Throat microphone (IASUS NT, IASUS Concept Ltd.) * | Over laryngopharynx |
| Sejdic et al. [39] | Dual-axis accelerometer (ADXL322) | Anterior to cricoid cartilage, along anterior-posterior and superior-inferior axes |
| Skowronski et al. [40] | Miniature surface-mounted MIC (VT506, Voice Technologies, Zurich, Switzerland) | Laterally below the cricoid cartilage |
ACC: accelerometer; MIC: microphone; NM: Source not mentioned; and sEMG: surface electromyography. * Articles mentioned that it is a multimodal system, but other modalities were not presented.