All the patients were informed about the aim and procedures of the study and written informed consent was obtained from all the participants. The pre-post pilot study group included inpatients affected by a first stroke (i.e. ischemic or hemorrhagic) occurred no longer than 6 months before the enrolment (mean distance from onset 4.1 ± 1.5 months). Presence of severe upper limb paresis (0 to 1 point according to the Medical Research Council scale) of the following muscles: deltoid, biceps brachii, triceps brachii, flexor carpi radialis, flexor carpi ulnaris, extensor carpi radialis, extensor carpi ulnaris, flexor digitorum and extensor digitorum; passive range of motion (ROM) completely free; absence of primary joint trauma of the wrist, elbow and shoulder, were considered as inclusion criteria. All patients who refused to participate were excluded from the study together with ones presenting: increased muscle tone defined as a score higher than 1 point (modified Ashworth scale) in at least one of the treated muscles described above for MRC assessment, apraxia (De Renzi test < 62 points) , global sensory aphasia (clinical notes), neglect (clinical notes), cognitive impairments (Mini Mental State Examination MMSE < 24 points) , sensitivity disorders (defined as < 2 points in items shoulder, elbow, wrist and thumb at the proprioceptive sensitivity section of the Fugl-Meyer scale), stroke lesion located in the cerebellum (clinical notes). The institutional review board of the IRCCS San Camillo Hospital Foundation (Italy) approved the study protocol (Prot. 2012.07 BAT v.1.2) and the study have been conducted in accordance with the Declaration of Helsinki.
During the treatment patient was lying supine with the upper limbs positioned in symmetric posture. The subject was asked to move both limbs with the same frequency performing bilateral flexion-extension of one of the upper limb districts according to the available free ROM of the target joint. The movement execution of the affected arm was supported by the physiotherapist performing the passive movement at the same rhythm, as the one executed with the unaffected side. During the therapeutic session patient was asked to focus his/her attention on the movement performed against gravity, which was reinforced by a verbal command. Afterwards, the physiotherapist fully supported movement execution coherently with the patient’s movement initialization. The active movements performed voluntarily by the patient with unaffected limb were considered as the reference movement, that the physiotherapist has to emulate passively, by synchronization of passive movement executed in phase with the affected side. The treatment lasted one hour and was divided as follows: 2 proprioceptive based stimulation sessions per 3 min for each movement, with a rest of 2 min between every session. Every patient received 15 treatments, 5 days a week, for 3 weeks. The PBT was introduced as additional hour to conventional neuromotor treatment (CNT). Each patient received CNT, based on tailored individual exercises (passive, active-assisted or active), in accordance with the patient’s functional status and with the aim to: reduce degree of disability, improve quality of life. The patients performed exercises for postural control in sitting and standing position, exercises for coordination with and without physiotherapist assistance and gait training, whether appropriate.
However, the upper limb motion were trained providing only PBT and passive mobilization, to maintain mechanical properties of soft tissues.
Clinical outcome measures
The assessment was conducted by two physiotherapists not involved in providing the experimental treatment. The following domains were assessed at the beginning and at the end of treatment: muscles strength, motor impairment and functional activities. The primary outcomes were: the Medical Research Council (MRC) scale  and force measured by dynamometer. The following muscles were considered: deltoid, biceps brachii, triceps brachii, flexor carpi radialis, flexor carpi ulnaris, extensor carpi radialis, extensor carpi ulnaris, flexor digitorum and extensor digitorum. The secondary outcomes were: the Fugl-Meyer upper extremity (F-M UE) scale  for upper limb motor function, the Functional Independence Measure (FIM) scale for global independence , the modified Ashworth scale for spasticity . Positions for dynamometer test were standardized as requested for MRC scale assessment. Data were recorded on study case report sheet form, which contained the patient’s study number, date of enrolment, pre and post assessment results, adverse events, and clinical data. Completed form was registered on study management database.
The descriptive results were reported as mean and standard deviation. Moreover, distribution skewness was assessed by Shapiro-Wilk test and due to the small sample size non-parametric test for paired measures (Wilcoxon) was used to determine the differences before and after treatment. Statistical significance level was set at p < 0.05 and IBM SPSS 20.0 package software was used for the analysis.