214 MMN CIDP PSMA CIAP Table 2 Percentage of patients exposed to cooling Patient group Any Bathing Weather Swimming Cold pack 96 90 97 72 20 23 17 8 96 88 97 72 30 29 26 8 20 8 9 4 MMN multifocal motor neuropathy; CIDP chronic inﬂammatory demyelinating polyneuropathy; PSMA progressive spinal muscular atrophy; CIAP chronic idiopathic axonal polyneuropathy The results of the last nerve conduction studies, per- formed prior to the questionnaire, were reviewed for presence of deﬁnite conduction block (segmental reduction in negative compound muscle action potential area of at least 50% in any nerve) and probable conduction block (segmental reduction in negative compound muscle action potential amplitude of at least 30% in an arm nerve) [27]. Conduction studies included the median nerve (recording from the thenar and ﬂexor carpi radialis muscle), ulnar nerve, radial nerve, and musculocutaneous nerve up to Erb’s point, and the peroneal and tibial nerves up to the knee [27]. These nerves were studied bilaterally, except for ﬁve patients with CIDP and the patients with CIAP who were studied unilaterally. Conduction block in arm or leg nerves was found in all MMN patients, in 82% of CIDP patients, and in none of the PSMA or CIAP patients (Table 1). MMN patients had conduction block in arm nerves more often than CIDP patients. Questionnaire The questionnaire consisted of temperature-related and weakness-related items. Questions concerned the year preceding the questionnaire to reduce recall bias. First, we asked if symptoms of weakness and conditions of cooling or warming had occurred. Conditions of cooling included a stay in cold weather, the use of cold packs or taking a cold shower, bath or swim. Conditions of warming included a stay in hot weather, the use of hot packs or electric blan- kets, rinsing the hands in hot water while washing dishes or taking a warm or hot shower, bath or swim. If symptoms of Table 3 Percentage of patients exposed to warming J Neurol (2011) 258:212–217 weakness and conditions of cooling or warming had occurred, we asked if weakness increased during cooling (cold paresis) or warming (heat paresis). Exposure to cooling or warming and increase in weakness were entered as dichotomous variables. Prior to the study, the ques- tionnaire was tested for inconsistencies and feasibility by a randomly chosen sample of 20 patients who visited our outpatient clinic for neuromuscular disorders with symp- toms of weakness and who were not included in this study. Statistical analysis We calculated the frequency of symptoms of cold (or heat) paresis in arms with established weakness and in legs with established weakness. We determined if: (1) exposure to cooling and warming differed between patient groups, and (2) the percentage of patients with CIDP, PSMA, or CIAP reporting symptoms of cold or heat paresis differed from the percentage of patients with MMN reporting symptoms of cold or heat paresis (Chi-square tests). Next, univariate and multivariate binary logistic regression analyses were performed. The determinant of interest was presence of MMN with CIDP, PSMA, and CIAP as reference groups. Outcome variables included: (1) symptoms of cold paresis in arms or legs, (2) symptoms of cold paresis in arms, (3) symptoms of cold paresis in legs, (4) symptoms of heat paresis in arms or legs, (5) symptoms of heat paresis in arms, and (6) symptoms of heat paresis in legs. Age and disease duration were assessed as continuous variables. The possible confounders sex, age (in years), and disease duration (in years) at the time of the questionnaire were added in the multivariate models. Version 15.0.1 of the SPSS statistical software program (Chicago, IL, USA) was used for all analyses. p values \0.05 were considered to be signiﬁcant. Results Exposure to cooling or warming did not differ signiﬁcantly between MMN, CIDP, and PSMA, but CIAP patients were signiﬁcantly less often exposed to cooling than MMN and Any 100 98 97 96 90 92 97 76 82 90 80 60 Sauna 26 19 20 0 12 2 3 0 Patient group MMN CIDP PSMA CIAP 123 MMN multifocal motor neuropathy; CIDP chronic inﬂammatory demyelinating polyneuropathy; PSMA progressive spinal muscular atrophy; CIAP chronic idiopathic axonal polyneuropathy Bathing Weather Hot pack Electric blanket Dish-washing 22 13 14 20 62 65 54 52