Spatial and temporal summation of pain evoked by mechanical pressure stimulation

Abstract

Chronic pain patients often suffer from widespread and long lasting pain. The integrative effect of combined spatial and temporal summation on pain intensity has not been quantitatively tested. The present study was designed to investigate: (1) if the size of the stimulation area would facilitate the temporal summation of pain to repetitive pressure stimulation, and (2) if temporal summation is effective when stimulating separated sites, repetitively. Twenty healthy male subjects participated in this study. The test sites were located on the bilateral upper trapezius and tibialis anterior muscles. The ten stimuli (each with a duration of 1s) were applied to a single site at three inter-stimulus intervals (ISI: 1, 5, 30s) using five different probe sizes (0.5, 1, 2, 4 and 8cm(2)). The stimulation intensity was equal to the pressure pain threshold (PPT) determined for each probe size. Similar repetitive stimulations at two inter-stimulus intervals (5s and 30s) using two sizes of probes (0.5cm(2) and 2cm(2)) were applied to ten separate sites. The PPT at the trapezius muscle decreased significantly with the increase in stimulus area from 0.5cm(2) to 8cm(2) (P<0.001) due to spatial summation. Temporal summation of pain was evoked by repetitive pressure stimuli on the same site for all ISI and was more pronounced at 5s and 30s ISI with larger probe areas (2, 4, and 8cm(2)) compared to smaller probe areas. There was no temporal summation of pain to stimuli with ISI 5 and 30s when stimulating the separated sites. The current study indicated that spatial summation facilitated the temporal summation of pain for stimuli given at 5s and 30s ISI. The combination of temporal and spatial integration of nociceptive input facilitates the pain intensity, suggesting that temporal summation is clinically relevant in conditions with widespread pain.

Assessment and manifestation of central sensitisation across different chronic pain conditions

“…However, when more standardisation is required, automated user-independent methods are needed such as thermal (Kong et al, 2013), pressure (Nie et al, 2009), or electrical stimulation techniques of the skin (Arendt- Nielsen et al, 1994), muscles (Arendt- Nielsen et al, 1997b;Skou et al, 2013), and viscera .…”

“…thermodes (Price et al, 1989;Coghill et al, 1993;Nielsen and Arendt-Nielsen, 1997), pressure probes (Greenspan et al, 1997;Nie et al, 2009), or cuffs (Polianskis et al, 2002).…”

A Human Experimental Bone Pain Model

“…Experiment 1. The rationale behind experiment 1 was to investigate whether the area of stimulation could influence pressure pain threshold (PPT) [16]. It was hypothesized, that if the same force increase rate was used, the duration of the stimuli would be longer for higher thresholds than lower thresholds.…”

“…As the sensory threshold and perceived intensity are affected by increased stimulation area, manifested as decreased pain threshold and increased pain intensity, it is important to investigate whether the stimulus duration could influence the threshold when using probes of different sizes [16]. Hamilton et al showed that pressure with a metal probe on the anterior surface of the tibia evoked pain [17].…”

Efeitos local e sistêmico do laser de baixa potência no limiar de dor por pressão em indivíduos saudáveis

“…Foram realizadas três marcações: a primeira (algometria na região da mão) a 3 cm da extremidade distal da tabaqueira anatômica, em direção à linha média do primeiro músculo interósseo dorsal 34,35 ; a segunda (algometria na região da perna) foi feita no ponto médio do músculo tibial anterior [36][37] ; e na terceira (aplicação do laser entre os pontos desenhados na região da mão), foram realizados dois pontos com distância de 1 cm 2 entre eles, em direção ao polegar, e outros dois foram realizados com 1 cm 2 de distância entre eles em direção ao segundo metacarpo.…”