Measurements of skin temperature responses to cold exposure of foot and face in healthy individuals: variability and influencing factors

Confounding factors in peripheral thermal recovery time after active cooling

OBJECTIVES

The effectiveness of normal physiological thermoregulation complicates differentiation between pathologic changes in medical thermography associated with peripheral artery disease and a number of other clinical conditions. In this study we investigate a number of potential confounding factors to the thermal recovery rate after active limb cooling, with the main focus on age and sex.

APPROACH

The source data consists of 53 healthy individuals with no diagnosed cardiovascular disease or reported symptoms and with a mean age of 38.4 (± 12.1) years. The sample population was further divided into male (N = 14) and female groups (N = 39). The thermal recovery time was measured using two thermal cameras from both lower limbs on plantar and dorsal sides. The active cooling was achieved using moldable cold pads placed on the plantar and dorsal side of the lower limb. The recovery was measured until the temperature had reached a stable level. The recovery time was determined from an exponential fit to the measured data.

RESULTS

The correlation between the thermal recovery time constant and age varied from low to moderate linear correlation (0.31 ≤ ⍴ ≤ 70), depending on the inspected region of interest, with a higher statistically significant correlation in the medial regions. The contralateral limb temperature differences or the thermal time constants did not have statistically significant differences between the male and female sexes. Further, the secondary metrics such as participant's body mass, body-mass index, or systolic blood pressure had low or no correlation with the thermal recovery time in the study group.

CONCLUSION

The thermal recovery time constant after active cooling appears as a relatively independent metric from the majority of the measured potential confounding factors. Age should be accounted for when performing thermal recovery measurements. However, dynamic thermal imaging and its methodologies require further research and exploration.

Reproducibility of Skin Temperature Response after Cold Stress Test Using the Game Ready System: Preliminary Study

The objective of this preliminary study was to determine the reproducibility of lower limbs skin temperature after cold stress test using the Game Ready system. Skin temperature of fourteen participants was measured before and after cold stress test using the Game Ready system and it was repeated the protocol in four times: at 9:00, at 11:00, at 19:00, and at 9:00 h of the posterior day. To assess skin temperature recovery after cold stress test, a logarithmic equation for each region was calculated, and constant (β₀) and slope (β₁) coefficients were obtained. Intraclass correlation coefficient (ICC), standard error (SE), and within-subject coefficient of variation (CV) were determined. No differences were observed between measurement times in any of the regions for the logarithmic coefficients (p > 0.38). Anterior thigh (β₀ ICC 0.33–0.47; β₁ ICC 0.31–0.43) and posterior knee (β₀ ICC 0.42–0.58; β₁ ICC 0.28–0.57) were the regions with the lower ICCs, and the other regions presented values with a fair and good reproducibility (ICC > 0.41). Posterior leg was the region with the better reproducibility (β₀ ICC 0.68–0.78; β₁ ICC 0.59–0.74; SE 3–4%; within-subject CV 7–12%). In conclusion, cold stress test using Game Ready system showed a fair and good reproducibility, especially when the posterior leg was the region assessed.

Radial Pulse and Electrocardiography Modulation by Mild Thermal Stresses Applied to Feet: An Exploratory Study with Randomized, Crossover Design

OBJECTIVE

To investigate the changes in radial pulse induced by thermal stresses (TSs).

METHODS

Sixty subjects were enrolled. Using an open-label, 2×2 crossover randomization design, both feet of each subject were immersed in 15 °C water for cold stress (CS) and in 40 °C water for heat stress (HS) for 5 min each. Radial pulse, respiration and electrocardiogram (ECG) signals were recorded before, during and immediately after the TSs.

RESULTS

The analysis of heart rate variability revealed that CS increased the low-frequency (LF) and high-frequency (HF) components (P <0.05) and that HS reduced the LF and HF components (P <0.01). Both TSs reduced the normalized LF, increased the normalized HF, and reduced the LF/HF ratio. The differences in the ECG signals were more dominant during the TS sessions, but those in the radial pulse signals became more dominant immediately after the TS sessions. CS decreased the pulse depth (P <0.01) and increased the radial augmentation index (P <0.1), and HS increased the pulse pressure (P <0.1) and subendocardial viability ratio (P <0.01). There were no significant differences in pulse rate during the three time sequences of each TS. The respiration rate was increased (P <0.1), and the pulse rate per respiration (P/R ratio) was significantly decreased (P <0.05) with CS. The HF region (10-30 Hz) of the pulse spectral density was suppressed during both TSs.

CONCLUSIONS

CS induced vasoconstriction and sympathetic reactions, and HS induced vasodilation and parasympathetic reactions. Based on definitions used in pulse diagnosis, we made the novel discoveries that the pulse became slower (decreased P/R ratio), more floating and tenser under CS and that the HF region of the spectral power decreased significantly under both TSs.

Abnormal thermography in Parkinson's disease

BACKGROUND

An autonomic denervation and abnormal vasomotor reflex in the skin have been described in Parkinson's disease (PD) and might be evaluable using thermography with cold stress test.

METHODS

A cross-sectional pilot study was undertaken in 35 adults: 15 patients with PD and abnormal [(123)I]-metaiodobenzylguanidine cardiac scintigraphy and 20 healthy controls. Baseline thermography of both hands was obtained before immersing one in cold water (3 ± 1 °C) for 2 min. Continuous thermography was performed in: non-immersed hand (right or with lesser motor involvement) during immersion of the contralateral hand and for 6 min afterward; and contralateral immersed hand for 6 min post-immersion. The region of interest was the dorsal skin of the third finger, distal phalanx.

RESULTS

PD patients showed a lower mean baseline hand temperature (p = 0.037) and greater thermal difference between dorsum of wrist and third finger (p = 0.036) and between hands (p = 0.0001) versus controls, regardless of the motor laterality. Both tests evidenced an adequate capacity to differentiate between groups: in the non-immersed hand, the PD patients did not show the normal cooling pattern or final thermal overshoot observed in controls (F = 5.29; p = 0.001), and there was an AUC of 0.897 (95%CI 0.796-0.998) for this cooling; in the immersed hand, thermal recovery at 6 min post-immersion was lesser in patients (29 ± 17% vs. 55 ± 28%, p = 0.002), with an AUC of 0.810 (95%CI 0.662-0.958).

CONCLUSIONS

PD patients reveal abnormal skin thermal responses in thermography with cold stress test, suggesting cutaneous autonomic dysfunction. This simple technique may be useful to evaluate autonomic dysfunction in PD.

Efficacy and safety of Korean red ginseng for cold hypersensitivity in the hands and feet: a randomized, double-blind, placebo-controlled trial

ETHNOPHARMACOLOGICAL RELEVANCE

In Korean medicine, the steamed root of Panax ginseng C.A. Meyer, known as Korean red ginseng (KRG), is used to invigorate the body, enhance qi, and improve blood flow. It is a potential treatment for cold hypersensitivity in the hands and feet (CHHF), a common complaint among Asians, especially women. However, few studies of its efficacy and safety for CHHF have been conducted.

MATERIALS AND METHODS

This randomized, double-blind, placebo-controlled trial included 80 female patients with CHHF at Kyung Hee University Hospital at Gangdong, Seoul, Korea. The participants took six capsules of 500-mg KRG powder or placebo twice daily for 8 weeks and were followed up for 4 weeks. The primary outcome measure was change in skin temperature of the hands. The secondary outcome measures included change in skin temperature of the feet, visual analog scale (VAS) scores of CHHF severity, recovered temperature (RT) of the hands after cold stress test, distal-dorsal difference (DDD) in temperature of the hands, power variables of heart rate variability (HRV), and 36-item Short-Form Health Survey (SF-36) scores.

RESULTS

The KRG group had significantly higher skin temperature of the hands and feet, lower VAS scores, higher RT of the right 5th finger, and less parasympathetic activity than the placebo group at 8 weeks. No significant differences were noted in DDD of the hands and SF-36 scores. No serious adverse events were reported during the study.

CONCLUSIONS

Peripheral vasodilation by KRG may alleviate CHHF. Further controlled studies are required to elucidate the effects of KRG on the autonomic nervous system.

Effect of Korean red ginseng on cold hypersensitivity in the hands and feet: study protocol for a randomized controlled trial

Background

Cold hypersensitivity in the hands and feet (CHHF) is one of the most common complaints among Asians, especially in women. Korean red ginseng (KRG), which is a steamed form of Panax ginseng, has vasodilating action in the peripheral vessels and increases blood flow under cold stress. However, few studies have evaluated the effect of KRG on cold hypersensitivity.

Methods/Design

This trial is a randomized, double-blind, placebo-controlled trial in 80 CHHF patients. The trial will be implemented at Kyung Hee University Hospital at Gangdong in Seoul, Korea. The participants will take KRG or a placebo for eight weeks, after which they will be followed-up for four weeks. During the administration period, six capsules of 500 mg KRG or placebo will be provided twice a day. The primary outcome is change of skin temperature in the hands between baseline and after treatment. The secondary outcomes include the visual analogue scale scores of cold hypersensitivity in the hands, change of skin temperature and the VAS scores of cold hypersensitivity in the feet, the recovery rate of the skin temperature by the cold stress test of the hands, the distal-dorsal difference of the hands, power variables of heart rate variability, and the 36-item short form health survey.

Discussion

This study is the first trial to evaluate the efficacy of KRG on CHHF by using infrared thermography. Our study will provide basic evidence regarding CHHF.

Trial registration

CliniacalTrials.gov NCT01664156

Skin temperature responses to cold stress in patients with severe motor and intellectual disabilities

Patients with severe motor and intellectual disabilities (SMID) often suffer from autonomic nervous system disturbances. At the same time, the caregivers of patients with SMID face challenges to understand the patients' chronic health problems effectively by simply observing them. Therefore, recognizing specific symptoms is important to improve support for SMID. We investigated the autonomic nervous function in patients with SMID with skin vasomotor responses to cold stimuli. The relationship of the results of cold stress and autonomic symptoms observed by the main caretakers was also examined. We analyzed 38 patients with SMID. Their hand skin temperature was measured before and after cold stimuli using infrared thermography. A 'distal-dorsal difference' (DDD) at baseline, and the recovery rate of the second fingertip and dorsum were calculated. All main caregivers filled out questionnaires evaluating autonomic symptoms. The recovery rate of the second fingertip and dorsum after cold stimuli was lower than 80% in 64% and 60% patients, respectively. The baseline DDD was greater than 1 °C in 84% of the patients. A DDD>1 °C was associated with a reduced recovery rate. All caregivers recognized some autonomic-related symptoms. Patients with constipation or snoring demonstrated a reduced recovery rate. However, none of the observed symptoms can predict the presence of a reduced rate with cold stimuli in a statistically significant way. This study showed excessive sympathetic nerve activities in patients with SMID. The baseline DDD could be a valuable parameter accessing their microvascular circulation. To improve the life of a person with SMID, accessing autonomic function using a noninvasive method, such as thermography is warranted without directly observed symptoms.