Validation of a sternal skin conductance criterion for measuring hot flashes in breast cancer patients

Automatic Detection of Hot Flash Occurrence and Timing from Skin Conductance Activity

Hot flashes (HF) are intense, transient feelings of heat usually accompanied with flushed skin and sweating that are experienced by women around the time of menopause. HFs are associated with poor quality of life and increased cardiovascular risk. Automatic detection of HF occurrence and precise timing of HF onset could provide unique insight into the physiology of the HF and its effect on the cardiovascular system. A novel automatic algorithm is proposed for the detection of HFs occurrence and timing from the sternal skin conductance signal that is robust to noise and artifacts. The method is based on the gold standard rule (2μS rise in skin conductance within 30 s) and considers several conditions based on the skin conductance level and its derivative to reject unwanted events. ECG-derived heart rate pattern variations are studied prior to the detected HF onset. The algorithm is validated against expert detected HFs over 200 hours of sleep data collected from 12 perimenopausal women. It achieved a total accuracy of 93% and a total error of 3% in HF detection. It was observed that heart rate increased before the onset of 80% of the HFs occurring in undisturbed sleep. Application of this algorithm along with fusion of other simultaneously recorded physiological measures has the potential to advance understanding of the HF.

Is anxiety associated with hot flashes in women with breast cancer?

OBJECTIVE

Women with breast cancer are at higher risk for experiencing hot flashes (HFs), which is attributable, in large part, to systemic cancer treatments and their effects on estrogen levels. However, other factors, such as anxiety, could also play a role. This study aimed to assess the cross-sectional and temporal relationships between anxiety and HFs among women treated for breast cancer and to clarify the direction of these relationships.

METHODS

Fifty-six women recently treated for breast cancer were assessed prospectively using a 14-day Hot Flashes and Anxiety Diary (HFAD). Anxiety and HFs were also assessed using the Hospital Anxiety and Depression Scale-anxiety subscale and the Menopause-Specific Quality of Life Questionnaire-vasomotor subscale. In addition, HFs were objectively recorded for a continuous 24-hour period using home-based sternal skin conductance.

RESULTS

No cross-sectional relationship was found between anxiety and subjectively assessed HFs, or between anxiety and the frequency and intensity of objectively assessed HFs. However, a greater anxiety level on the HFAD was significantly associated with a shorter time to reach the HF peak, as assessed with sternal skin conductance (partial Spearman correlation coefficient rsp = -0.44). Moreover, greater anxiety predicted more severe self-reported HFs on the following night, both assessed with the HFAD (rsp = 0.13). Conversely, self-reported diurnal and nocturnal HFs on the HFAD did not predict next-day anxiety level.

CONCLUSIONS

This study reveals a significant relationship between anxiety and faster-developing objectively measured HFs. Furthermore, anxiety has been found to significantly predict subsequent increases in self-reported HFs, suggesting that strategies that target anxiety could potentially have a beneficial effect on HFs in women with breast cancer.