- 期刊
交感神經皮膚反應習慣化過程之波型
Waveform Symmetry during the Habituation Process of Sympathetic Skin Response
摘要
對自律神經系統的檢查，交感神經性皮膚反應(sympathetic skin response, SSR)是常被使用的工具。比起其他困難費時的臨床檢查，交感神經皮膚反應具有簡單和非侵入性的優點。過去的研究常利用此檢查，比較病人兩側的SSR反應活性在單側的神經疾病（例如腦中風）所表現出的差異。但先前的研究很少針對健康受試者分析SSR在兩側的對稱性。並且過去的研究，多是將誘發SSR的電刺激施於受試者單側的肢體，如此亦可能影響SSR在兩側肢體的對稱性。此外SSR有所謂習慣化(habituation)的現象，先前的研究亦很少去分析習慣化過程中SSR 對稱性的變化。本篇研究施與電刺激在健康受試者額頭，誘發一系列的SSR，來分析兩側SSR於習慣化過程中的對稱性。 本研究以20位健康受試者進行SSR測試。其中包括6位男性，14位女性，年齡在20歲至40歲。我們在受試者兩側手部記錄SSR反應，而誘發SSR的電刺激則是施於受試者額頭眉心處，共施予電刺激10次，每次間隔30秒。在兩側手部各記錄到10次的反應波，分析所有的左右手反應波振幅比值並取其對數值，作以下三種分析：(1)個體內SSR波型的變異性：我們分析20位受試者每個人所有的左右手反應波振幅比值取對數後的平均值和變異性，以比較每個個體內的SSR 波型變異。(2)個體間SSR 波型的變異：取所有20位受試者其第一次電刺激的反應波為一組，第二次電刺激的反應波為一組，以此類推到第十次的反應波為一組，分析這10組的平均振幅大小和兩側振幅比值對數值的變異性是否有相關性。(3)波型和左右對稱性的分析：我們根據先前Toyokura對SSR的研究，將SSR的反應波分為兩種波型：P波和N波，來分析反應波型與兩側振幅對稱性的關係。 結果顯示即使在眉心電刺激的情況下，同一受試者其左右手SSR的相對振幅比值仍有相當的變異，這表示SSR的習慣化的機轉可能包含有周邊的因素存在。並且當進入習慣化過程，隨著反應波的平均振幅變小，或是反應波型趨於N波時，兩側振幅比值的變異性也愈來愈大。因此我們建議，在比較病人兩側的SSR反應活性所表現出的差異時，應選取P波型和一開始振幅較大的反應波型，來作兩側差異性的比較，會有較為穩定的結果。
關鍵字
交感神經性皮膚反應並列摘要
For investigating autonomic function, sympathetic skin response (SSR) is usually used as a non-invasive test. In previous studies, SSR was applied in the patients with neurological diseases (such as stroke), and the amplitude of SSR was compared between the left and right hand (or foot). Most researchers used electrical limb stimulation to elicit SSR in both limbs. However, the symmetry of SSR in healthy subjects has not been well established. Besides, SSR testing may affect the symmetry of SSR. Moreover, although habituation phenomena are commonly seen during SSR testing, few studies have discussed the symmetry of SSR during repetitive SSR testing. In this study the glabella (a midline location) was electrically stimulated in healthy subjects to elicit SSR in both hands and the relationship was analyzed between the symmetry of SSR and the process of habituation on both sides. A total of 20 healthy subjects (6 males and 14 females, age ranging from 23 to 35 years with a mean of 26.8) were recruited. SSRs were elicited in bilateral hands by stimuli (10 consecutive stimuli every 30 seconds) applied to the glabella. The amplitude ratio of left-to-right palmar response was transformed to base-10 logarithms for analysis. Three sets of analysis were performed: (1) Intra-subject SSR variation: The variability in the amplitude ratio logarithm of all response waves was studied in each subject. The standard deviation in the amplitude ratio logarithm of 20 subjects ranged from 0.025 to 0.15. (2) Inter-subject SSR variation: The response waves to the 1(superscript st) ES (electrical stimulation) of all subjects as a group and to the 2(superscript nd) ES as a group were classified. The standard deviation of the amplitude ratio logarithm in 10 groups increased significantly from 0.1 (ratio 1.28) at the 1(superscript st) stimulus to 0.185 (ratio 1.53) at the 10(superscript th) stimulus as the mean amplitude decreased from 8.72±3.01 mV (right palm) at the 1(superscript st) stimulus to 3.8±1.97 mV (right palm) at the 10(superscript th) stimulus. Increased variability was found as the mean amplitude of the response waves decreased (Spearman correlation: p=0.002). (3) Waveform and SSR variation: According to previous studies, all the SSR response waves were classified as either P waves or N waves. The standard deviation in the amplitude ratio logarithm was 0.121 (ratio 1.32) in the P wave group and 0.147 (ratio 1.40) in the N wave group. Increased variability was found in the N wave group (F test: p=0.003). Variability in the left-to-right amplitude ratio existed during the habituation process of healthy subjects. This suggested that a peripheral component may contribute to the mechanism of SSR habituation. Additionally, variability in the left-to-right amplitude ratio logarithms increased as SSR wave amplitude decreased or as N-type wave appeared in the habituation process. In conclusion, we suggest that initial SSR waves with larger amplitude or P type should be used to reduce variability in side-to-side comparisons.