What is the clinical significance of periodic limb movements during sleep?

To understand better the clinical impact of periodic limb movements during sleep (PLMS) we analysed data from 51 patients who, following an adaptation night, presented a PLMS index > 5 during two consecutive nocturnal polysomnographic recordings. In the morning following each recording patients completed a questionnaire including five visual analogic scales (VAS): (1) I did not sleep well/I slept very well. (2) I feel very sleepy/I do not feel sleepy at all. (3) I feel very tired/I feel very dynamic. (4) Physically, I do not feel fit/physically, I feel fit. (5) Psychologically, I do not feel fit/psychologically, I feel fit. We compared the responses to these questions with the PLMS index, first inter-individually, then intra-individually between nights. RESULTS: The inter-individual analysis did not show correlations between the PLMS index and the questions (1) and (2). We found a significant correlation between the PLMS index and the questions (3) (r = -0.29; P < 0.05), (4) (r = -0.30; P < 0.05) and (5) (r = -0.39; P < 0.01). For the intra-individual analysis, we did not find correlations between the PLMS index and questions (1)-(3), but found a significant correlation with questions (4) (r = -0.28; P < 0.05) and (5) (r = -0.36; P < 0.01). CONCLUSION: PLMS per se, or the sleep changes induced by them, seem to be associated with decreased physical and psychological fitness on awakening.