Device for electrical muscle stimulation

Abstract

A muscle electrostimulation device (1) comprises generators (21, 22) configured to deliver electrostimulation signals, and electrodes (4a, 4b, 4c, 4d) configured to be applied to a subject's body, preferably mounted on a single application support (5). A routing unit (6) is placed between the generators (21, 22) and the electrodes (4a, 4b, 4c, 4d). In the routing unit (6) there are routing elements (64), such as relays, switches or similar devices, which can be controlled to connect and disconnect different branches of conductive paths (63a, 63b, 63c) between input and output terminals (61, 62) of the routing unit (6). A control unit (3) stores and executes stimulation programmes, each identified by a distinct combination of states of the routing elements (64), to establish different combinations of electrical connections between the terminals (21a, 21b, 22a, 22b) of the generators (21, 22) and the electrodes (4a, 4b, 4c, 4d).

Description

[0001] Device for electrical muscle stimulation

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention is developed in the field of muscle electrostimulation by means of alternating and / or pulsed electrical signals transmitted to the area of interest of the body by suitable electrodes, in accordance with the preamble of claim 1.

[0005] Prior art

[0006] Electrostimulation is a technique whereby appropriate electrical signals are used to induce contractions of the body's muscles in order to train / tonify / remodel the muscles in such a way as to, for example, aid the training of an athlete or to rehabilitate a hypotonic patient.

[0007] The signals are generated by special voltage generators and are transmitted to electrodes that are applied directly to the skin, at the muscle that has been chosen to be treated. Specifically, such voltage generators are configured to generate an electrical signal that mimics the action potential normally transmitted to the muscle for its contraction by the central nervous system.

[0008] It is recognised that different effects on the muscle can be achieved through different parameters of the electrical signal, including waveform, duration, intensity and frequency, as well as through appropriate electrode arrangements. For example, the generated signal may be sinusoidal or square wave. Interferential currents, obtained by feeding two pairs of electrodes placed orthogonally to each other from two generators at different frequencies, are known to encounter less tissue resistance and thus penetrate more easily without releasing excessive energy into the skin, thereby preventing feelings of discomfort. Problems of the background art

[0009] Today, electrostimulation is a process that requires specially trained personnel to apply the electrodes in the most appropriate way and execute the desired stimulation programme. Instead, it would be desirable to simplify the process to make it accessible also to untrained personnel.

[0010] Summary of the invention

[0011] The purpose of the present invention is to overcome the disadvantages described in connection with the known technique, in particular to provide a device for muscle electrostimulation capable of performing the desired programmes without having to change the positioning of the electrodes, and to maximise the effectiveness of the electrostimulation process.

[0012] This and other purposes are achieved by an electrostimulation device according to any one of the attached claims.

[0013] Advantages of the invention

[0014] According to an embodiment, the device is provided with a routing unit that is interposed between the generators and the electrodes. The routing unit includes controllable routing elements, which allow different circuit branches of the routing unit to be connected and disconnected. A controller controls the routing elements according to various stimulation programs, which involve connecting different electrodes to different terminals of the generators from time to time.

[0015] Advantageously, stimulation programmes with different spatial distributions of the stimulation signals can be selected after application of the electrodes, although the electrodes can always be applied in the same standard arrangement. This optionally makes it possible to mount the electrodes on a single support, so that the electrodes do not have to be applied individually on the body, but only have to be applied on the support. Moreover, if one wants to change the stimulation programme, it is not necessary to disconnect and reconnect the electrodes, but particular stimulation programme sequences can be preset.

[0016] In other embodiments, different electrode assemblies may be applied simultaneously to different parts of the body, while the control unit provides for stimulating each part of the body with a specific stimulation program, potentially different for different parts of the body.

[0017] Further features and advantages of the invention will be recognisable by a person skilled in the art from the following detailed disclosure of exemplary embodiments of the invention.

[0018] Brief disclosure of the figures

[0019] For a better understanding of the following detailed disclosure, some embodiments of the invention are illustrated in the accompanying drawings, wherein:

[0020] - figure 1 schematically shows an electrostimulation device according to an embodiment of the invention,

[0021] - figure 2 shows schematically a routing unit of the figure 1 device,

[0022] - figure 3 schematically shows an electrostimulation device according to another embodiment of the invention,

[0023] - figure 4 shows an example of paths of the electrostimulation signals of the device of figure 1 or 3, when a cross stimulation program is executed,

[0024] - figures 5a and 5b show examples of electrostimulation signal paths of the device of Figure 1 or 3, when two distinct parallel stimulation programs are performed, and

[0025] - figures 6a-6d show examples of the electrostimulation signal paths of the device in figure 1 or 3, when four distinct convergent stimulation programmes are performed.

[0026] DETAILED DESCRIPTION

[0027] A device for muscle electrostimulation is indicated in the figures by the number 1. Device 1 comprises a plurality of generators 21, 22, which are exemplified in the two generators 21, 22 in the example in figure 1.

[0028] Each generator 21, 22 is configured to generate an electrical signal suitable for electrostimulation of a muscle.

[0029] The electrostimulation signal is an alternating or pulsed signal with a frequency of its own, preferably in mid-frequency. The electrostimulation signal can for example be a sinus wave signal or a square wave signal.

[0030] Each generator 21, 22 can be controlled to activate and interrupt the generation of the electrostimulation signal. In particular, device 1 comprises a control unit 3, which is in signal communication with generators 21, 22 and is configured to control the activation of generators 21, 22. The deactivation of generators 21, 22, with the interruption of the electrostimulation signal, can be controlled again by control unit 3, or can be timed from their activation.

[0031] Each generator 21, 22 has electric terminals 21a, 21b, 22a, 22b, preferably two electric terminals 21a, 21b, 22a, 22b, through which generator 21, 22 is configured to deliver the electrostimulation signal.

[0032] The separate terminals 21a, 21b, 22a, 22b of a generator 21, 22 in particular are configured to deliver the same electrostimulation signal, but with different phases between them, e.g. in phase opposition.

[0033] Therefore, if at a given moment one terminal 21a, 22a of a generator 21, 22 is positive, the other terminal 21b, 22b of the same generator 21, 22 is negative, in the case of alternating signals, or neutral for pulsed signals. The two polarities are reversed at the frequency of the electrostimulation signal.

[0034] Device 1 comprises a plurality of electrodes 4a, 4b, 4c, 4d, configured to be applied to a subject's body. In the illustrated embodiment, the electrodes 4a, 4b, 4c, 4d are shaped as plates that can, for example, have a quadrangular shape.

[0035] The electrodes 4a, 4b, 4c, 4d are electrically connected to the terminals 21a, 21b, 22a, 22b of the generators 21, 22, as described in more detail below, to transmit the electrostimulation signals in the body of the subject to which they are applied. Ideally, the electrodes 4a, 4b, 4c, 4d are equal in number to twice the number of generators 21, 22, i.e. equal to the total number of terminals 21a, 21b, 22a, 22b of generators 21, 22. In this way, each terminal 21a, 21b, 22a, 22b of each generator 21, 22 can be connected to a separate electrode 4a, 4b, 4c, 4d, in one or more modes of use. In the embodiment of figure 1, four electrodes 4a, 4b, 4c, 4d are thus illustrated.

[0036] It should be emphasised that the electrostimulation signal of a generator 21, 22, when transmitted in a subject's body, propagates predominantly along a path of minimum impedance in the patient's body, between the positions of electrodes 4a, 4b, 4c, 4d fed by the different terminals 21a, 21b, 22a, 22b of the generator 21, 22.

[0037] From the point of view of the stimulated muscle, a possible exchange of position of the two electrodes 4a, 4b, 4c, 4d connected to the two terminals 21a, 21b, 22a, 22b of a generator 21, 22 is indifferent, although the presence of electrodes 4a, 4b, 4c, 4d connected to both terminals 21a, 21b, 22a, 22b remains necessary to allow the passage of current.

[0038] When multiple electrodes 4a, 4b, 4c, 4d are connected to terminals 21a, 21b, 22a, 22b of different generators 21, 22, and applied on the body of the same subject, in the case of multiple isofrequency electrostimulation signals, unexpected signal paths could be generated in the subject's body, between electrodes 4a, 4b, 4c, 4d close to each other and connected to separate generators 21, 22. Therefore, it is preferable that the frequencies of the electrostimulation signals are distinct for at least two separate generators 21, 22, in particular if they are connected to electrodes 4a, 4b, 4c, 4d which are intended for locations close to each other, optionally distinct frequencies for all generators 21, 22.

[0039] In some designs, as shown in figures 4 to 6d, device 1 comprises an application holder 5 to which electrodes 4a, 4b, 4c, 4d are mounted in a predetermined arrangement. The application support 5 is configured to be applied to the body of the subject, so as to bring the electrodes 4a, 4b, 4c, 4d into contact with the body. The support 5 may for example be a flexible band attachable to the body, for example a band provided with Velcro.

[0040] However, embodiments without a single support 5 are also provided, wherein each electrode 4a, 4b, 4c, 4d is individually attachable to the body. For example, known electrodes capable of performing this function are pinch electrodes, suction cup electrodes, adhesive electrodes, and plate electrodes to be kept attached to the body by gel patches. Instead, if the holder 5 is provided, the electrodes 4a, 4b, 4c, 4d can be held in place by the holder 5.

[0041] Different possible arrangements of electrodes 4a, 4b, 4c, 4d on the holder 5, as well as dimensions and conformations of the holder 5, can be contemplated, depending on the number of electrodes 4a, 4b, 4c, 4d, the type of target muscle chosen, and the stimulation programmes planned.

[0042] The arrangement of the electrodes 4a, 4b, 4c, 4d on the support 5, in particular of each set of four electrodes 4a, 4b, 4c, 4d, may be a quadrilateral, e.g. square or rectangular, arrangement. Therefore, for each electrode 4a, there is an opposite electrode 4b and two adjacent electrodes 4c, 4d. Opposite and adjacent electrodes can also be identified in other provisions than the quadrilateral one.

[0043] In particular, where electrodes 4a, 4b, 4c, 4d are arranged at vertices of a polygon, two electrodes 4a, 4c are considered adjacent if their vertices are connected to each other by (outer) sides of the polygon, while two electrodes 4a, 4b are considered opposite if they are connected to each other by (inner) diagonals of the polygon.

[0044] Even in the absence of application supports 5, electrodes 4a, 4b, 4c, 4d are preferably intended to be arranged in the same predefined arrangement, with opposite and adjacent electrodes, e.g. quadrilateral. Ideally, electrodes 4a, 4b, 4c, 4d have visual indications, e.g. a colour code, to identify their designated position in the predefined arrangement. In a real-life example, different colours can be used for a first pair of electrodes 4a, 4b, intended for placement opposite each other, and for a second pair of electrodes 4c, 4d, intended for placement opposite each other.

[0045] According to one aspect of the invention, the device 1 comprises a routing unit 6, electrically connected between the generators 21, 22 and the electrodes 4a, 4b, 4c, 4d.

[0046] In particular, the routing unit 6 comprises input terminals 61 and output terminals 62. Input terminals 61 are electrically connected to separate terminals 21a, 21b, 22a, 22b of generators 21, 22, while output terminals 62 are electrically connected to separate electrodes 4a, 4b, 4c, 4d.

[0047] An internal electrical circuit connects input terminals 61 and output terminals 62. As will be detailed below, the internal electrical circuit is configured to be reconfigurable in order to connect different output terminals 62 to different input terminals 61 from time to time. In some configurations, one or more output terminals 62 may also be isolated from each input terminal 61.

[0048] Accordingly, thanks to the routing unit, electrodes 4a, 4b, 4c, 4d can be electrically connected to terminals 21a, 21b, 22a, 22b of generators 21, 22, in order to receive the electrostimulation signals to be transmitted into the subject's body. From time to time, each electrode 4a, 4b, 4c, 4d may be connected to the same terminal 21a, 21b, 22a, 22b of the same generator 21, 22, or to another terminal 21a, 21b, 22a, 22b of the same generator 21, 22, or to terminals 21a, 21b, 22a, 22b of different generators 21, 22.

[0049] In some embodiments, a single routing unit 6 is provided, whose terminals 61, 62 are connected to all terminals 21a, 21b, 22a, 22b of all generators 21, 22, and to all electrodes 4a, 4b, 4c, 4d.

[0050] In other embodiments, the device 1 comprises a plurality of routing units 6, connected to distinct generators 21, 22 and electrodes 4a, 4b, 4c, 4d. Specifically, the generators 21, 22 may be divided into a plurality of generator groups 21, 22, and the electrodes 4a, 4b, 4c, 4d may be divided into a plurality of electrode groups 4a, 4b, 4c, 4d. For each routing unit 6, the input terminals 61 are electrically connected to the terminals 21a, 21b, 22a, 22b of the generators 21, 22 of a respective single group of generators 21, 22, and are not connected to the terminals 21a, 21b, 22a, 22b of the generators 21, 22 of any other group of generators 21, 22. Similarly, the output terminals 62 of the routing unit 6 are electrically connected to the electrodes 4a, 4b, 4c, 4d of a respective single electrode group 4a, 4b, 4c, 4d, and not to the electrodes 4a, 4b, 4c, 4d of any other electrode group 4a, 4b, 4c, 4d.

[0051] In the embodiment of figure 3, four routing units, four sets of generators 21, 22, each with two generators 21, 22, and four sets of electrodes 4a, 4b, 4c, 4d, each with four electrodes 4a, 4b, 4c, 4d, are shown. For the sake of simplicity of illustration only, the electrical connections between the routing units 6 and the electrodes 4a, 4b, 4c, 4d of the relative groups have been illustrated as being partially grouped.

[0052] Ideally, the control of all generators 21, 22, and routing units 6 as described below, is delegated to a single control unit 3.

[0053] In one exemplary embodiment, all the electrode groups 4a, 4b, 4c, 4d are mounted on the same application support 5. For example, the application support 5 can be shaped to cover an area of the body with a plurality of muscles, and the electrodes 4a, 4b, 4c, 4d can be arranged on the application support 5 in such a way that distinct groups of electrodes 4a, 4b, 4c, 4d stimulate distinct muscles. Alternatively, separate brackets 5 can carry separate groups of electrodes 4a, 4b, 4c, 4d, or all electrodes 4a, 4b, 4c, 4d can be individually fixed to the body.

[0054] For each routing unit 6, the internal circuit comprises a plurality of branches of conductive paths 63a, 63b, 63c, and a plurality of routing elements 64 between the branches 63a, 63b, 63c.

[0055] Each input terminal 61 is directly connected to a respective input branch 63a, and each output terminal 62 is directly connected to a respective output branch 63c. In addition, intermediate branches 63b may be considered which are not directly connected to any input 61 or output terminal 62, but can only be connected to them via further branches 63a, 63b, 63c and routing elements 64. Each branch 63a, 63b, 63c can be a linear branch, with two and only two ends, or a branched branch, with three or more ends.

[0056] Each routing element 64 is arranged between a number of respective path branches 63a, 63b, 63c, and can be directly connected to them, particularly at their ends. Routing elements 64 can be controlled between respective states to connect and disconnect the respective path branches 63a, 63b, 63c.

[0057] In the illustrated embodiments, each routing element 64 is a relay, with three main terminals (preferably three and only three), also referred to as first, second, and third terminals. The relay terminals are connected to the ends of three respective separate path branches 63a, 63b, 63c. In addition to the main terminals, one or more control terminals, e.g. two, can be provided as known to control the operation of the main terminals. In the following, however, except where explicitly indicated, reference will be made to the main terminals of the routing elements 64.

[0058] As is known, a relay is controllable between several states, for example an excited state and a resting state. In a first state, the relay can connect the first and second terminals to each other, without connecting the third terminal to them, while in a second state, the relay can connect the first and third terminals to each other, without connecting the second terminal to them. It should therefore be noted that in the two states, a common terminal (the first) is connected to two distinct other terminals, one at a time (the second and third). Therefore, the relay is configured, in distinct states, to electrically connect distinct pairs of path branches 63a, 63b, 63c to each other, between the three path branches 63a, 63b, 63c connected to the relay. In other designs, routing elements 64 may include controllable switches, e.g. solid-state switches such as MOSFETs or IGBTs. In this case, each routing element 64 can only be directly connected to two respective branches 63a, 63b, 63c, to connect and disconnect them. In fact, each switch ideally has two main terminals and one control terminal.

[0059] Relays and switches may be used indifferently to perform the functions described below, although the use of either requires different numbers, arrangements and controls of routing elements 64 and conductive path branches 63a, 63b, 63c.

[0060] In what follows, reference will be made to the case of using relays, but a possible use of switches would be to replace each relay with a routing element 64 given by a pair of switches controlled to remain in opposite states, and arranged in such a way as to perform the same function as the corresponding relay together, connecting to three path branches 63a, 63b, 63c. Alternatively, the switches are not necessarily arranged in pairs to perform the same functions as a relay, but they are nevertheless arranged and controlled to connect and disconnect respective path branches 63a, 63b, 63c to each other, as can be obtained from an engineer in the field.

[0061] The branches 63a, 63b, 63c and the routing elements 64 are arranged such that in different combinations of the states of the routing elements 64, electrical connections of the output terminals 62 with different input terminals 61 are realized.

[0062] In particular, control unit 3 is configured to control not only generators 21, 22, but also routing elements 64. In fact, control unit 3 is configured to store a plurality of stimulation programmes. Each stimulation program is identified by a distinct combination of states of the routing elements 64. Therefore, different combinations of electrical connections between the terminals 21a, 21b, 22a, 22b of the generators 21, 22 and the electrodes 4a, 4b, 4c, 4d are realised in different stimulation programmes via the routing unit 6.

[0063] Note that it is not necessary that each electrode 4a, 4b, 4c, 4d be connected to two terminals 21a, 21b, 22a, 22b of different generators 21, 22 for the two stimulation programmes, but it is sufficient that at least one electrode 4a, 4b, 4c, 4d be electrically connected to terminals 21a, 21b, 22a, 22b of two different generators 21, 22, one at a time, in the two different stimulation programmes.

[0064] Stimulation programmes can be stored, e.g. in a memory unit, by control unit 3. This storage includes a look-up table showing the status of each routing element, e.g. indicated as 0 or 1, for each different stimulation programme.

[0065] Control unit 3 is then configured, e.g. by means of a microcontroller and respective firmware, to command the execution of a selected stimulation programme. This is performed by controlling the routing elements 64 to assume, each, the respective state corresponding to the selected stimulation programme, and by commanding the activation of one or more generators 21, 22 involved in the stimulation programme.

[0066] In this description, the term stimulation programme is used to designate a programme in which the same combination of states of the routing elements 64 is always maintained.

[0067] The invention advantageously also permits the application of dynamic stimulations, in which the states of the routing elements 64 and thus the combinations of connections between electrodes 4a, 4b, 4c, 4d and generators 21, 22 are changed during the transmission of the stimulation signals.

[0068] In this case, control unit 3 can be configured to store time sequences of stimulation programmes, and to execute a sequence of stimulation programmes by controlling the routing elements 64 to successively assume states corresponding to the stimulation programmes of the sequence, and if necessary by commanding appropriate activations and deactivations of the generators 21, 22.

[0069] In fact, as will be shown below, it is emphasised that in some stimulation programmes all generators 21, 22 may be involved, whereas in other stimulation programmes it is not necessary to activate all generators 21, 22. For example, in some stimulation programmes, terminals 21a, 21b, 22a, 22b of a particular generator 21, 22 may not be connected to any electrode 4a, 4b, 4c, 4d.

[0070] Below are some examples of combinations of connections between electrodes 4a, 4b, 4c, 4d and terminals 21a, 21b, 22a, 22b of generators 21, 22, relating to preferred stimulation programmes.

[0071] A first preferred stimulation program will be called a cross-stimulation program. It provides for a combination of states of the routing elements 64 such that a first pair of electrodes 4a, 4b opposite each other are electrically connected to distinct terminals 21a, 21b of a first generator 21, and a second pair of electrodes 4c, 4d opposite each other are electrically connected to distinct terminals 22a, 22b of a second generator 22.

[0072] This possibility is shown in figure 4 for a quadrilateral arrangement of electrodes 4a, 4b, 4c, 4d. It schematically shows the main propagation directions of the stimulation currents in the body, which are crossed with each other, in particular substantially perpendicular.

[0073] Theoretically, eight different combinations of connections between electrodes 4a, 4b, 4c, 4d and terminals 21a, 21b, 22a, 22b of generators 21, 22 can result in cross stimulation programmes. For example, if electrode 4a is connected to terminal 21a of the first generator 21, a second electrode 4c, adjacent to 4a, can be connected to one of the terminals 22a, 22b of the second generator 22. In both cases, the remaining two electrodes 4b, 4d will have to be chosen to respect the cross-programme. Similarly, two alternative combinations are available for any other of the four possible terminal choices 21a, 21b, 22a, 22b connected to the first electrode 4a.

[0074] On a practical level, these eight combinations are as effects at least partially repetitive with each other, because two terminals 21a, 21b, 22a, 22b of the same generator 21, 22 can always be swapped without consequence. In contrast, the number of non-repetitive combinations is two (exemplified as XI and X2 in Table 1, although it is not compulsory to select precisely these combinations from all possible repetitive combinations). Specifically, in a first cross-stimulation programme, the electrostimulation current from a first generator 21 predominantly travels along a first diagonal of the quadrilateral arrangement, and the electrostimulation current from a second generator 21 predominantly travels along a second diagonal of the quadrilateral arrangement. In a second cross-stimulation programme, the electrostimulation current from the first generator 21 predominantly travels along the second diagonal, and the electrostimulation current from the second generator 21 predominantly travels along the first diagonal.

[0075] A second preferred stimulation programme will be called a parallel stimulation programme. It provides for a combination of states of the routing elements 64 such that a first pair of electrodes 4a, 4c adjacent to each other are electrically connected to distinct terminals 21a, 21b of a first generator 21, and a second pair of electrodes 4b, 4d adjacent to each other are electrically connected to distinct terminals 22a, 22b of a second generator 22.

[0076] It should be noted that different stimulation programs can be performed with the same electrodes 4a, 4b, 4c, 4d and the same generators 21, 22. The designation of a particular electrode 4a, 4b, 4c, 4d as "first" should not necessarily be understood as the same between two different programs.

[0077] Even for parallel stimulation programs, there would be numerous theoretical combinations, repetitive between them. Of interest among the non-repetitive combinations are a row-parallel stimulation programme and a column-parallel stimulation programme (= and II in table 1, figures 5a, 5b). In the row programme, the first pair of adjacent electrodes 4a, 4c are on a first row and the second pair of adjacent electrodes 4b, 4d are on a second row. In the column programme, the first pair of adjacent electrodes 4a, 4d are on a first column and the second pair of adjacent electrodes 4b, 4c are on a second column.

[0078] A third preferred stimulation programme will be called the convergent stimulation programme. It provides for a combination of states of the routing elements 64 such that a single electrode 4a is electrically connected to a first terminal 21a of a generator 21, and a plurality of other electrodes 4b, 4c, 4d, preferably all other electrodes 4b, 4c, 4d, are electrically connected to a second terminal 21b of the same generator 21. Therefore, several paths in the subject's body will be followed by electrostimulation signals from the same generator, converging towards the single electrode 4a from all other electrodes 4b, 4c, 4d. In this condition, it is permissible that no electrodes 4a, 4b, 4c, 4d are connected to terminals 22a, 22b of the other generator 22.

[0079] Of interest among the non-repetitive combinations are four distinct convergent stimulation schedules (Cl, C2, C3 and C4 in Table 1, Figures 6a-6d) in which the aforementioned first electrode 4a is the one located at the four distinct vertices of the quadrilateral arrangement, respectively.

[0080] The following describes, with particular reference to figure 2, an exemplary embodiment of an internal electrical circuit of the routing unit 6, and the states of its routing elements 64 to realise the desired stimulation programmes.

[0081] In this example, the internal electrical circuit 6 was optimised to minimise the number of routing elements 64 such that, together, eight preferred stimulation programmes could be realised, i.e. two crossed, two parallel and four convergent programmes. In particular, there are nine routing elements 64 of the type connected with three path branches 63a, 63b, 63c, e.g. relays, numbered 64-1, 64-2, 64-3, 64-4, 64-5, 64-6, 64-7, 64-8 and 64-9. Each of the routing elements 64 can be controlled independently, but in the example illustrated, two of the routing elements (64-6 and 64-9) assume the same state in all stimulation programmes of interest, and thus can be jointly controlled (and Table 1 shows them in a single row).

[0082] Among the nine routing elements 64, there are four primary routing elements 64-1, 64-3, 64-5, 64-7. In a first state, each connects a respective output branch 63c to a respective input branch 63 a. In a second state, each connects the respective output branch 63c to a respective intermediate branch 63b.

[0083] In addition, among the nine routing elements 64, there are four secondary routing elements 64-2, 64-6, 64-8, 64-9. In two separate states, each connects a respective intermediate branch 63b to two separate input branches 63 a.

[0084] Finally, among the nine routing elements 64, there is a tertiary routing element 64-4 which, in a first state, connects a respective first intermediate branch 63b to a respective input branch 63 a, and in a second state, connects a respective first intermediate branch 63b to a respective second intermediate branch 63b.

[0085] It can therefore be appreciated that routing elements 64 are arranged in a cascading pattern on a number of levels, namely a first level, a second level and a third level. Each layer includes one or more routing elements 64.

[0086] In the illustrated exemplary embodiment, the first level is identified by the four primary routing elements 64-1, 64-3, 64-5, 64-7. Each of them has its first terminal (i.e. the common terminal which in the two different states is connected to two separate further terminals, which are the second and third) connected directly to a respective output terminal 62. Here and hereinafter, it will be understood that there is a direct connection between two elements when a route branch 63a, 63b, 63c connects these elements, without any other routing elements 64 being interposed between them.

[0087] The second level is identified by the routing elements 64-2, 64-4, 64-6, 64-8 (which are partly secondary and partly tertiary routing elements). Each has its first terminal directly connected to a second or third terminal of a routing element 64 of the first level.

[0088] The third level is identified by the routing element 64-9, the first terminal of which is directly connected to the second or third terminal of a routing element 64 of the second level.

[0089] This cascade structure can be extended or restricted, and the number of routing elements 64 at each level can vary, depending on the desired combinations of input and output terminals 61, 62, and the number of such terminals 61, 62 (and thus the number of electrodes 4a, 4b, 4c, 4d and generators 21, 22). It generally allows the number of possible combinations of connections to be multiplied, given the same number of routing elements 64.

[0090] Note that the cascade structure described can be directed in the opposite way to the example shown, in particular so that each routing element has its first terminal connected to a respective input terminal 61.

[0091] In addition, embodiments with only two levels or with more than three levels are permissible. In general, for all levels subsequent to the first, each routing element 64 has at least one terminal of its own connected to a routing element 64 of the immediately preceding level, in particular the respective first terminal connected to a second or third terminal of another routing element 64 belonging to an immediately preceding level. In other words, the routing elements 64 have a common orientation that progressively increases branching by proceeding in a predetermined direction between the input terminals 61 and the output terminals 62.

[0092] Below is a table showing the control states of the routing elements in figure 2, according to their numbering 64-1, 64-2, 64-3, 64-4, 64-5, 64-6, 64-7, 64-8, 64-9, for the eight preferred stimulation programmes. The state referred to as 0 is the state in which the routing element 64 under consideration connects its own terminal represented on the left with its own terminal represented at the top right; the state referred to as 1 is the state in which the routing element 64 under consideration connects its own terminal represented on the left with its own terminal represented at the bottom right.

[0093] Table 1

[0094] A second table is given below, in which we refer to each terminal 21a, 21b, 22a, 22b of generator 21, 22, the electrode 4a, 4b, 4c, 4d to which it is connected according to the eight stimulation programmes in Table 1. Table 2

[0095] Obviously a person skilled in the art will be able to make numerous equivalent modifications to the variants set forth above, without thereby departing from the scope of protection as defined by the appended claims.

Claims

CLAIMS1. Device for electrical muscle stimulation (1), comprising:- a plurality of generators (21, 22), each having electrical terminals (21a, 21b, 22a, 22b) and configured to deliver by means of the respective terminals (21a, 21b, 22a, 22b) an electrical stimulation signal with a respective frequency,- a plurality of electrodes (4a, 4b, 4c, 4d) configured to be applied to a body of a subject, and- a control unit (3), configured to control an activation of the generators (21, 22),- a routing unit (6), comprising input terminals (61) electrically connected to the terminals (21a, 21b, 22a, 22b) of the generators (21, 22), output terminals (62) electrically connected to the electrodes (4a, 4b, 4c, 4d), and an internal electrical circuit connecting the input terminals (61) and the output terminals (62), wherein the internal circuit comprises:- a plurality of conductive path branches (63a, 63b, 63c), and- a plurality of routing elements (64), each connected between respective path branches (63a, 63b, 63c) and controllable between respective states to connect and disconnect the respective path branches (63a, 63b, 63c) with each other, wherein the control unit (3) is configured for:- storing a plurality of stimulation programs, each stimulation program being identified by a distinct combination of states of the routing elements (64), to establish in the different stimulation programs different combinations of electrical connections between the terminals (21a, 21b, 22a, 22b) of the generators (21, 22) and the electrodes (4a, 4b, 4c, 4d), and- controlling the routing elements (64) to assume states corresponding to thestored stimulation programs, wherein each routing element (64) has three main terminals connected to three respective path branches (63a, 63b, 63c), and is configured, in distinct states, to connect to each other distinct pairs of path branches, among the three respective path branches (63a, 63b, 63c), by connecting in said distinct states a first terminal of its three main terminals to a second and a third terminal, respectively, of its three main terminals,- the routing elements (64) are arranged according to a cascade pattern on a plurality of levels of routing elements (64), with a first level and one or more successive levels, characterized in that:- each routing element (64) of each said one or more successive levels has the respective first terminal connected to a second or a third terminal of a routing element (64) of an immediately preceding level.

2. Device (1) according to claim 1, wherein said plurality of levels comprises at least two levels successive to said first level.

3. Device (1) according to claim 1 or 2, wherein each routing element (64) of the first level has its first terminal connected to a respective output terminal (62), or each routing element (64) of the first level has its first terminal connected to a respective input terminal (61).

4. Device (1) according to any one of claims 1 to 3, wherein:- said plurality of conductive path branches (63a, 63b, 63c) comprises input branches(63a) directly connected to respective input terminals (61), output branches (63c) directly connected to respective output terminals (62), and intermediate branches (63b) which are not directly connected to input and output terminals (61, 62),- the plurality of routing elements (64) comprises:- primary routing elements, each connecting, in a first state, a respective output branch (63 c) to a respective input branch (63 a), and in a second state, the respective output branch (63c) to a respective intermediate branch (63b),- secondary routing elements, each connecting, in two distinct states, a respective intermediate branch (63b) to two distinct input branches (63a), and- at least one tertiary routing element, each connecting, in a first state, a respective first intermediate branch (63b) to a respective input branch (63 a), and in a second state, the respective first intermediate branch (63b) to a respective second intermediate branch (63b).

5. Device (1) according to any one of claims 1 to 4, wherein, in each stimulation program, the respective combination of states of the routing elements (64) is such that each electrode (4a, 4b, 4c, 4d) is electrically connected to one and only one respective terminal (21a, 21b, 22a, 22b) of generator (21, 22), wherein at least one electrode (4a, 4b, 4c, 4d) is electrically connected to distinct terminals (21a, 21b, 22a, 22b) of a first generator (21, 22), one at a time, in at least two respective distinct stimulation programs, and to a terminal (21a, 21b, 22a, 22b) of a second generator (21, 22), in at least one further stimulation program.

6. Device (1) according to any one of claims 1 to 5, comprising an application support(5) configured to be applied to the body of the subject, wherein the electrodes (4a, 4b, 4c, 4d) are mounted to the application support (5) according to a predetermined arrangement, such as to define electrodes (4a, 4b, 4c, 4d) adjacent to each other and electrodes (4a, 4b, 4c, 4d) opposite each other, preferably a quadrilateral arrangement.

7. Device (1) according to any one of claims 1 to 6, wherein the electrodes (4a, 4b, 4c, 4d) have visual indications to identify respective designated positions of the electrodes (4a, 4b, 4c, 4d) according to a predetermined arrangement, such as to define electrodes (4a, 4b, 4c, 4d) adjacent to each other and electrodes (4a, 4b, 4c, 4d) opposite each other, preferably a quadrilateral arrangement.

8. Device (1) according to claim 6 or 7, wherein, in at least one cross stimulation program, preferably in each of two distinct cross stimulation programs, the respective combination of states of the routing elements (64) is such that a first pair of electrodes (4a, 4b) opposite each other are electrically connected to distinct terminals (21a, 21b) of a first generator (21), and a second pair of electrodes (4c, 4d) opposite each other are electrically connected to distinct terminals (22a, 22b) of a second generator (22).

9. Device (1) according to any one of claims 6 to 8, wherein, in at least one parallel stimulation program, preferably in each of two distinct parallel stimulation programs, the respective combination of states of the routing elements (64) is such that a first pair of electrodes (4a, 4c) adjacent to each other are electrically connected to distinct terminals (21a, 21b) of a first generator (21), and a second pair of electrodes (4b, 4d) adjacent to each other are electrically connected to distinct terminals (22a, 22b) of asecond generator (22).

10. Device (1) according to any one of claims 1 to 9, wherein, in at least one convergent stimulation program, preferably in each of four distinct convergent stimulation programs, the respective combination of states of the routing elements (64) is such that a single electrode (4a) is electrically connected to a first terminal (21a) of a generator (21), and a plurality of other electrodes (4b, 4c, 4d), preferably all the other electrodes (4b, 4c, 4d), are electrically connected to a second terminal (21b) of the same generator (21).

11. Device (1) according to any one of claims 1 to 10, comprising a plurality of generator groups (21, 22), a plurality of electrode groups (4a, 4b, 4c, 4d), a single control unit (3), and a plurality of routing units (6), wherein the input terminals (61) of each routing unit (6) are electrically connected to the terminals (21a, 21b, 22a, 22b) of the generators (21, 22) of a respective generator group (21, 22), and output terminals (62) of each routing unit (6) are electrically connected to the electrodes (4a, 4b, 4c, 4d) of a respective electrode group (4a, 4b, 4c, 4d).

12. Device (1) according to any of claims 1 to 11, wherein the control unit (3) is configured to store temporal sequences of stimulation programs, and to execute a sequence of stimulation programs by controlling the routing elements (64) to successively assume states corresponding to the stimulation programs of the sequence.

13. Device (1) according to any one of claims 1 to 12, wherein the frequencies of theelectrical stimulation signals are distinct for at least two distinct generators (21, 22).

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