the evaluation of motor function for duchenne muscular dystrophy ( dmd ) includes the 
 10-meter run , 6-minute walk test ( 6mwt ) , and the north star ambulatory assessment ( nsaa ) . these evaluation methods have also been used to determine the appropriate time to commence 
 corticosteroid therapy for patients with dmd . the reliability and validity of the 6mwt and 
 nsaa have been confirmed in a multi - center longitudinal study1 , and these assessment methods have been employed in clinical 
 studies2 . the outcomes of these tests 
 can help assess an individual s motor ability in detail ; however , these tests have certain 
 limitations when they are performed at a hospital . they are usually performed at the time of 
 the patient s visit to the hospital , which makes them less frequent and discontinuous . moreover , the results are easily influenced by the physical or emotional condition of the 
 patient . it has been reported that the amount of daily life activity for the motor - functional 
 evaluation of healthy children and pediatric diseases3,4,5,6 can be monitored using an 
 actigraph . furthermore , the amount of activity recorded by an actigraph has been used as the 
 main outcome index to reflect the amount of physical activity in the home environment of 
 patients with dmd6 . although , these 
 reports did not compare the results of actigraph monitoring with conventional motor - function 
 evaluation methods , their results suggest actigraph assessment of daily life activity can be 
 used to evaluate motor function as effectively as the conventional motor - function tests . moreover , an actigraph can easily and non - invasively record consecutive data . in this study , whether an actigraph can be used to effectively monitor the changes in the 
 motor function of a patient with dmd before and after corticosteroid administration was 
 examined by comparing the results with conventional motor - function evaluation methods . the subject s 
 body weight was 17 kg and his body mass index and serum creatine kinase were 15.1 
 kg / m and 24,030 u / l , respectively . a nonsense mutation was identified in exon 
 21 of the patient s dystrophin gene . the actigraph ( mtn-210 , estera , saitama , japan ) was constantly attached to the patient s 
 lower waist , except during bathing , during the evaluation period . data were collected for 14 
 days before and 14 days after the administration of corticosteroids , until his next visit to 
 the hospital . the collected data were analyzed using dedicated software ( sleepsign act , 
 kissei comtec , matsumoto , japan ) . the evaluation index was calculated by taking the mean 
 energy expenditure and number of steps per day . statistical analysis was performed using the 
 unpaired student s t - test and pasw statistics software ( version 22.0 , spss , inc . , chicago , 
 il , usa ) . during the 14 days before and after the administration of corticosteroids , the 
 patient did not participate in any high - momentum activities such as athletic events . conventional motor - function tests , the 10-meter run , 6mwt , and nsaa , were performed by the 
 patient at the time of hospital visits ( once a month ) . the difference in the results of each 
 test was examined before and after corticosteroid administration . the 6mwt was performed in 
 two ways  the way it is conventionally defined by the american thoracic society7 ( conventional 6-minute walk test ; c6mwt ) , 
 and in the way described in our recent report , paced by the sound of a metronome ( periodic 
 sound - based 6-minute walk test ; ps6mwt)8 . in this 
 test , the subject initially walked for one minute to a long - interval metronome sound , and 
 the distance walked was measured . the sound interval was then gradually shortened , and the 
 subject walked for one minute at each of the metronome beat intervals . the best periodic 
 sound was determined as that when the subject walked the longest distance in one minute . the 
 subject then walked , paced by the best periodic sound , for six minutes . since the distance 
 covered in the ps6mwt by both healthy subjects and those with dmd is significantly longer 
 than the distance in the c6mwt , the ps6mwt provides a better indication of ambulatory 
 potential in the evaluation of physical endurance than the c6mwt8 . this study was approved by the institutional ethics committee of the shinshu university 
 school of medicine , japan ( approval number : 2,340 ) . the study was orally explained to the 
 subject and his parents , and they consented to participation in the experiment . in the assessment of the daily life activity of the dmd patient , the mean energy 
 expenditure before and after corticosteroid administration was 1,108.7  137.2  kcal / day and 
 1,246.0  127.0  kcal / day , respectively , and the difference between the two values of mean 
 energy expenditure was statistically significant ( p=0.024 ) . furthermore , the mean number of 
 steps before and after the administration were 10,081.8  2,638.7 steps / day and 12,205.0  
 1,695.4 steps / day , respectively , and the difference between these values was also 
 significant ( p=0.033 ) . these significant increases were observed at just 14 days after the 
 start of corticosteroid administration ( table 
 1table 1.actigraph results before and after the corticosteroid administrationbefore administrationafter administrationnumber of steps ( steps / day)10,081.8  2,638.712,205.0  1,695.4energy expenditure ( kcal / day)1,108.7  137.21,246.0  127.0 * p<0.05 , unpaired student s t - test ) . * p<0.05 , unpaired student s t - test the results of the conventional motor - function tests at the time of the patient s visit 
 before and after corticosteroid administration were as follows . the time of the 10-meter run 
 after administration was 0.43 seconds less than that before administration ( table 2table 2.conventional motor function test results before and after the corticosteroid 
 administrationbefore administrationafter administrationdifference10-m run ( s)4.43.70.43c6mwt ( m)3663726ps6mwt ( m)37539318nsaa ( score)22/3429/347c6mwt : conventional 6-minute walk test ; ps6mwt : periodic sound based 6-minute walk 
 test ; nsaa : north star ambulatory assessment ) . the distance of the 6mwt after administration was longer than that before 
 administration ( 6  m longer in the c6mwt and 18  m longer in the ps6mwt ) ( table 2 ) . the nsaa score increased to 29 points from 22 points 
 ( table 2 ) . the maximum increase was seen in 
 the  one - leg jump  item of the nsaa . the increase from a score of zero ( indicating 
 impossibility ) to two ( indicating the highest score ) was confirmed for both legs of the 
 patient . c6mwt : conventional 6-minute walk test ; ps6mwt : periodic sound based 6-minute walk 
 test ; nsaa : north star ambulatory assessment in this study , the evaluation of the amount of daily activity and conventional 
 motor - function tests were used to assess a patient with dmd before and after corticosteroid 
 administration . the energy expenditure and number of steps taken by the patient increased 
 after corticosteroid administration . daily activity measured using an actigraph and using 
 conventional motor - function evaluation tests indicated the same tendency . in this study , the conventional motor - function tests were scheduled once a month , but on 
 one occasion , there was a gap of more than two months between the tests . the main reasons for the low and 
 discontinuous frequency of evaluations were the long distance between patient s residence 
 and the hospital , and the unstable physical and emotional condition of the patient . the actigraph measured data at any 
 place and time , which made statistical analysis possible using the data collected during a 
 period of just 14 days . our results show that an actigraph can be easily and noninvasively used to monitor daily 
 life activity on consecutive days for the evaluation of motor activity before and after 
 corticosteroid administration . furthermore , the evaluation of motor activity using an 
 actigraph is consistent with the results of conventional motor - function tests . future 
 studies addressing this topic should include a large number of subjects and evaluate motor 
 functions over a longer period to determine the utility of the actigraph as a primary tool 
 for measuring the outcome of clinical trials and to evaluate the efficacy of therapeutic 
 agencies .