Characteristic Autonomic Nervous Activity of Institutionalized Elders with Dementia

This study clarified the characteristic autonomic nervous activity of institutionalized elders diagnosed with dementia using Hasegawa’s Dementia Scale-Revised. Twenty-six healthy adult persons (HPs) in their 20 s 40 s met the inclusion criteria, and 16 persons (27.6 ± 8.2 years old) completed the research procedure. Of 70 persons with dementia (PDs) residing at the one geriatric health services facilities, only 24 persons met the inclusion criteria, and only nine (N = 9, 83.44 ± 9.45 years old) completed the procedure. Actigraph and ambulatory electrocardiographic instruments measuring autonomic nervous activity were attached to the subjects for 24 hours. Activities and behaviors of PDs and HPs were observed by clinically experienced staff nurses and care workers. High frequency (HF) power indicating parasympathetic activity and LF/HF ratio indicating sympathetic activity were calculated. When awake, PDs’ LF/HF ratio was significantly lower than HP’s (Z = −2.60, p < 0.01), showing significant differences in the LF/HF ratios between waking and sleeping, more than those of the PDs (p < 0.001). Similarly, when awake, significant positive correlations were observed in the LF/HF ratio and actigraph activity count (AC) in 11 HPs and 3 PDs (range r = 0.17 to 0.49, p < 0.05); however, significant negative correlation was found in HF and AC of 12 HPs and 3 PDs (range r = −0.55 to −0.18, p < 0.05). While sleeping, significant positive correlations were observed in LF/HF and AC of 3 HPs and 1 PD (range r = 0.35 to 0.42, p < 0.05) and significant negative correlation was found in the HF and AC of 1 HP (r= −0.32, p < 0.001) and 1 PD (r = −0.32, p < 0.05). The mean value of LF/HF in a wakeful state was significantly lower for PDs than HPs. Combined results of behavioral observation, actigrapy and heart rate variability (HRV) analyses suggested that PDs showed positive correlations between LF/HF and AC in a wakeful state. Compared to those who showed no positive correlation, they did not require much nursing care. Corresponding author.