Table 1.
Summary of characteristics of participants, design, and analysis related to studies presented in the literature review.
| References | Age groups (in years) | Sample size | Stimuli | Range of localization (in degrees) | Statistical measure (s) |
|---|---|---|---|---|---|
| Abel et al. (2000) | 7 age groups: 10–19, 20–29, 30–39, 40–49, 50–59, 60–69, 70–81. Means and standard deviations were not provided. | 16 per age group | Broadband noise. One-third-octave noise band centered on 0.5 kHz and 4 kHz. Duration = 300 ms | Horizontal plane: 15–165 | ANOVA and Regression |
| Abel and Hay (1996) | 3 age groups: Young-Normal (18–38), Old-Normal (41–58), Old-Hearing Impaired (42–73). Means and standard deviations were not provided. | N = 24 Young-Normal, N = 24 Old-Normal, N = 23 Old-Hearing Impaired | Broadband noise. One-third octave noise bands centered at 0.5 or 4 kHz. Duration = 300 ms. | Horizontal plane: 30 to 150 | ANOVA |
| Addleman et al. (2019) | 2 age groups: Younger (21–33), Older (58–78). Means and standard deviations were not provided. | N = 13 Younger, N = 12 Older | Pink noise bursts. Frequency range = 0.2–8 kHz. Duration = 200 ms. | Horizontal plane: 10 to 180 | ANOVA |
| Briley and Summerfield (2014) | 3 age groups: Young (M = 22.9, SD = 2.8), Younger-Old (M = 65.1, SD = 3.6), Older-Old (M = 76.8, SD = 2.5) | N = 6 Young, N = 6 Younger-Old, N = 5 Older-Old | Summed pure tone frequencies/pink noise. Frequency range = 0.1–5 kHz. Duration = 1,510 ms. | Horizontal plane: 0 to 75 | Descriptive statistics |
| Brungart et al. (2017) | 2 are groups: Normal Hearing (M = 31.9), Hearing Impaired (M = 54.7). Standard deviations were not provided. | N = 16 Normal Hearing, N = 20 Hearing Impaired | 7 periodic chirp signals. Frequency range = 0.1–15 kHz. Stimulus duration either 250, 100, or 4,000 ms. | Horizontal plane = −150 to +150 Vertical plane = −28 to +28 | Correlation and Regression |
| Dobreva et al. (2011) | 3 age groups per experiment: Experiment 1: Young (19–41), Middle Age (45–66), Elderly (70–81). Experiment 2: Young (19–37), Middle Age (51–66), Elderly (71–81). Means and standard deviations were not provided. | Experiment 1: N = 19 Young, N = 11 Middle Age, N = 12 Elderly. Experiment 2: N = 8 Young, N = 7 Middle Age, N = 6 Elderly | Band-limited, flat spectrum, Gaussian noise bursts. Duration = 150 ms. | Horizontal plane = −60 to +60 Vertical plane = −25 to +25 | ANOVA |
| Fink et al. (2005) | 2 age groups: Younger (M = 25), Elderly (M = 61.7). Standard deviations were not provided. | N = 20 per group | 2 sound signals: clicks or pure tones. Clicks were noise, rectangular pulses. Duration = 1 ms. Sinusoidal tones 0.8 and 1.2 kHz. Duration = 10 ms. | Not applicable. Temporal order (lateralization) task. Sounds presented via headphones. | ANOVA |
| Freigang et al. (2014) | 2 age groups: Young (M = 24.1, SD = 2.3), Older (M = 68.1, SD = 5.5) | N = 22 Young, N = 53 Older | Narrowband noise centered at 0.5 (0.375–0.75 kHz) and 3.0 kHz (2.25–4.5 kHz). Duration = 500 ms. | Horizontal plane: −98 to +98 | ANOVA, T-test, and Correlation |
| Kolodziejczyk and Szelag (2008) | 3 age groups: Young (M = 22, SD = 1.1), Elderly (M = 66, SD = 0.7), Very Old (M = 101.1, SD = 0.11) | N = 17 Young, N = 18 Elderly, N = 11 Very Old | 300 Hz square tones. Duration = 15 ms. | Not applicable. Temporal order (lateralization) task. Sounds presented via headphones. | ANOVA |
| Otte et al. (2013) | 3 age groups: Children (M = 9.5, SD = 1.3), Young Adults (M = 24.9, SD = 4.9), Older Adults (M = 68.4, SD = 4.7) | N = 18 Children, N = 10 Young Adults, N = 14 Older Adults | Gaussian white noise high-pass filtered at 0.5 kHz or low-pass filtered at 5, 7, 11, or 20 kHz. Duration = 150 ms. | Horizontal plane = −75 to +75 Vertical plane = −55 to +55 | T-test and Correlation |
| Rønne et al. (2016) | 2 age groups: Normal Hearing (M = 39, SD = 11), Hearing Impaired (M = 64, SD = 15) | N = 13 Hearing Impaired, N = 11 Normal Hearing | White noiseband pass filtered to 0.4–16 kHz. Duration of stimulus not provided. | Horizontal plane: 0 to 120 | ANOVA |
| Savel (2009) | Age treated as a continuous variable. 48 individuals between 18 and 48 (M = 31, SD = 10), 2 individuals 61 and 62 (M = 61.5, SD = 0.5) | N = 48 Young, N = 2 Older | Filitered noise 0.25–2 kHz. Duration = 50 ms. | Horizontal plane: −77 to +77 | Correlation |
| Szymaszek et al. (2006) | 2 age groups: Young (M = 24 yrs., 8 months), Elderly (M = 64 yrs., 6 mos.) Standard deviations were not provided. | N = 17 Young, N = 16 Elderly | “Clicks.” No further description provided. Duration = 1 ms. | Not applicable. Temporal order (lateralization) task. Sounds presented via headphones. | ANOVA and Newman–Keuls |
| Whitmer et al. (2014) | Age treated as a continuous variable. Median = 63. Means and standard deviations were not provided. | N = 35 | 0.1 kHz click train. Duration = 500 ms. | Horizontal plane: −30 to +30 | T-test and Correlation |
| Whitmer et al. (2021) | Age treated as a continuous variable. No specific age information was provided. Based on Figure 1, it appears participants ranged in age from 20 to 70. | N = 28 | Speech segments with either 5- or 10-kHz cutoff frequency. Duration >5,000 ms. | Horizontal plane: −90 to +90 | ANOVA and Correlation |