Establishment of Norms for Facial Discriminative Sensitivity in Healthy Women Aged 45-60 Years: A Reference Framework

Abstract

Background/Objectives: In the context of facial surgery, particularly reconstructive procedures, sensory recovery is a critical yet often underexplored aspect of functional rehabilitation. Sensory-motor recovery can be considered a key marker of integration following reconstructive surgery. Among sensory modalities, discriminative sensitivity is typically the last to recover, making its evaluation particularly relevant. While established norms for hand sensitivity exist in the literature, there is a paucity of data regarding facial sensitivity. The objective of this study was to evaluate the discriminative sensitivity of the face in a population of healthy women aged 45-60 years. Methods: A total of 20 healthy women were included between January and March 2013. Participants had no history of facial pathologies or trauma. Discriminative sensitivity was measured using the Disk-Criminator™ device across eight facial zones. A detailed mapping of the tested areas was performed. Data obtained were compared with the existing literature. Statistical analyses included Shapiro-Wilk tests for normality, followed by Student's t-tests for group comparisons. To account for small sample size and verify robustness, non-parametric Mann-Whitney U tests were also performed. Adjustment for multiple comparisons was applied using the Bonferroni correction (adjusted α = 0.0125). Results: The mean age of participants was 52.3 years (±4.0 years). Discrimination threshold values ranged from 2.9 to 14.3 mm. Comparison with existing studies showed no significant age-related differences in zone 2R (cheek) and zone 8 (lower lip), suggesting stable sensitivity in these regions across adulthood. However, a significant decline in sensitivity with age was observed only in zone 1R (forehead), with a p-value < 0.001 after Bonferroni correction. Conclusions: We established a reference framework for cutaneous discriminative sensitivity across eight facial zones. These norms can serve as a baseline for the assessment and monitoring of patients with facial pathologies. Furthermore, our findings contribute to a better understanding of age-related sensory changes.

Keywords: aging and sensory perception; facial discriminative sensitivity; normative values; sensory recovery; two-point discrimination (TPD) test.

Figure 1

Two-point discrimination device (i.e., “Disk-Criminator™”).

Figure 2

Anatomical localization of the eight facial zones assessed: zone 1R (forehead, V1), zone 2R (cheek, V2), 3R (jaw, V3), 4 (nose), 5 (philtrum), 6 (chin, V3), 7 (upper lip), and 8 (lower lip).

Figure 3

Distribution of two-point discrimination thresholds across the eight facial zones in 20 healthy women aged 45–60 years. Facial zones are presented in the following order: zones 1R (forehead), 2R (cheek), 3R (jaw), 4 (nose), 5 (philtrum), 6 (chin), 7 (upper lip), and 8 (lower lip). Each boxplot displays median, interquartile range, and individual data points. Statistical comparisons with previously published normative data (Novak et al., 1993 [15]) were performed using paired Student’s t-tests; significance level was adjusted using Bonferroni correction (α = 0.0125).

Figure 4

Comparison of two-point discrimination thresholds from the current study and three previously published datasets for zones 1R (forehead), 2R (cheek), 6 (chin), and 8 (lower lip). Sample sizes range from n = 19 to 20 depending on zone completeness. A significant difference (*) was observed in zone 1R (forehead) compared to Novak et al. (1993) [15] (p = 5.46 × 10⁻⁸) [12,14].

Figure 5

Standardized facial map of two-point discrimination thresholds with 95% confidence intervals. This map illustrates the mean discriminative thresholds (in mm) and corresponding 95% confidence intervals for each tested facial region in women aged 45–60 years, providing normative reference values for clinical assessment.