Abstract:
An adjustable headgear assembly ( 10 ) for securing a respiratory interface device ( 26 ) to the head of a patient that includes a headgear member ( 12 ) that fits over the crown and back portion of a human head. The headgear member ( 12 ) has upper side portions ( 14 ) positionable above and forward of the ears of a human head and lower side portions ( 16 ) positionable below the ears and along the back portion of the head. A pair of upper retention members ( 20 ) are provided. Each pair of upper retention members ( 20 ) extends downwardly and forwardly from the upper side portions ( 14 ). A pair of lower retention members ( 30 ) extend forwardly and upwardly from each of the side portions. Each pair of upper ( 20 ) and lower ( 30 ) retention members are structured to engage a respiratory interface device ( 26 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/140,304 filed on Dec. 23, 2008, the contents of which are herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to adjustable headgear assemblies and, more particularly, to adjustable headgear assemblies used in conjunction with respiratory interface devices. 
     BACKGROUND OF THE INVENTION 
     Respiratory interface devices are used for various reasons. Typically a respiratory interface device includes a mask portion interconnected with a source of breathable fluid to be inhaled by a patient. Examples of uses of these devices include the delivery of anesthesia, non-invasive ventilation, and for providing positive air pressure to a patient in the treatment of obstructive sleep apnea. In the treatment of obstructive sleep apnea, positive air pressure is provided to a patient while the patient is sleeping. 
     Accordingly, in uses such as the treatment of obstructive sleep apnea, mask comfort is important to ensure that the patient may sleep and also to ensure that the patient complies with the treatment. For the treatment of obstructive sleep apnea, the mask must provide a sufficient seal to enable pressure to be maintained within the airway of the patient. 
     Typical respiratory interface devices are bulbous and enclose a large portion of the nose and engage the face of the patient. Additionally, such devices are typically secured to a patient&#39;s head via the use of multiple straps and other apparatus. It is common for such devices to include a forehead support and related straps to counteract the forces exerted on the device by the conduit or other member supplying the breathable fluid to the mask and thus maintain proper alignment of the mask. These devices tend to be cumbersome to position and secure on a patient&#39;s head and also produce a claustrophobic effect on the patient. Examples of such devices and related headgear can be found in U.S. Pat. Nos. 5,517,986; 6,119,694, and 7,069,932. 
     SUMMARY OF THE INVENTION 
     In one embodiment, the invention provides an adjustable headgear assembly comprising a headgear member structured to fit over the crown and back portion of a human head. The headgear member includes upper side portions positionable at least one of above and forward of the ears of a human head and lower side portions positionable at least one of below the ears of a human head and along the back portion of a human head. The headgear assembly further comprises a pair of upper retention members, one of the pair of upper retention members extending downwardly and forwardly from each of the upper side portions and a pair of lower retention members, one of the pair of lower retention members extending forwardly and upwardly from each of the lower side portions. Each of the pair of upper retention members and each of the pair of lower retention members are structured to engage a respiratory interface device. 
     The pair of upper retention members and the pair of lower retention members may be structured to adjustably retain the respiratory interface device on a human head. Each of the pair of upper retention members may extend downwardly at an angle of between 5 degrees and 40 degrees and each of the pair of lower retention members may extend upwardly at an angle of between 5 degrees and 25 degrees. Each of the pair of upper retention members may comprise a strap member having a hook and loop portion structured to adjustably engage the respiratory interface device and each of the lower retention members may comprise a strap member having a hook and loop portion structured to adjustably engage the respiratory interface device. 
     The upper retention members and the lower retention members may be integrally formed with the headgear member. Each upper side portion may include a reinforcement member coupled thereto. Each of the upper strap members may be adjustably coupled to a respective one of the upper side portions. Each of the upper retention members may include an elastic portion and each of the lower retention members may include an elastic portion. Each of the upper retention members and each of the lower retention members may be adjustably coupled to the headgear member. One of the upper elastic members may comprise a first portion of a unitary elastic member and a corresponding one of the lower elastic members may comprise a second portion of the unitary elastic member. Each of the upper retention members may include a generally inelastic portion and each of the lower retention members may include a generally inelastic portion. Each of the upper retention members may comprise a first portion of a unitary member and a corresponding one of the lower retention members may comprise a second portion of a unitary member. 
     Each unitary member may include a first end coupled to one of the upper side portions, an opposite second end adjustably coupled to a corresponding one of the lower side portions, and an intermediate portion disposed between the first end and the opposite second end, with the intermediate portion being structured to engage a respiratory interface device. Each unitary member may include a first end adjustably coupled to one of the upper side portions, an opposite second end coupled to a corresponding one of the lower side portions, and an intermediate portion disposed between the first end and the opposite second end, the intermediate portion being structured to engage a respiratory interface device. Each unitary member may include a first end adjustably coupled to one of the upper side portions, an opposite second end adjustably coupled to a corresponding one of the lower side portions, and an intermediate portion disposed between the first end and the opposite second end, with the intermediate portion being structured to engage a respiratory interface device. 
     The headgear member may further include a secondary adjustment member having a first end and an opposite second end, the first end being coupled to one of the upper side portions and the second end being adjustably coupled to a corresponding one of the lower side portions. The second end of the secondary adjustment member may be further coupled to the opposite second end of the unitary member. The other one of the upper retention members may comprise a fourth portion of the elastic member and the other one of the lower retention members may comprise a third portion of the unitary member. The unitary member may be adjustably coupled to the headgear member. Each of the lower side portions may include an upward extending portion terminating at an adjustable portion, the adjustable portion engaging a respective one of the upper retention members. 
     These and other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a headgear assembly in accordance with an embodiment of the invention shown positioned on a human head; 
         FIGS. 2-8  are side views of headgear assemblies in accordance with other embodiments of the invention shown positioned on a human head; 
         FIG. 9  shows a schematic representation of the forces exerted on a tip of the nose interface device by headgear assemblies in accordance with embodiments of the invention; and 
         FIG. 10  shows a schematic representation of the forces exerted on a oral-nasal interface device by headgear assemblies in accordance with embodiments of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back, forward, rearward, above and below and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. 
     As employed herein, the statement that two or more parts or components are “coupled” together shall mean that the parts are joined or operate together either directly or through one or more intermediate parts or components. As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality). 
     One potential solution to providing less cumbersome respiratory interface devices has been to try to reduce the amount of mounting points and strap members associated with the headgear used in conjunction with a given respiratory interface device. However, most headgears with only a 2-point mounting fail to provide a stable mounting on the patient due to the lack of upper and lower force vectors acting on the respiratory interface device that is typically present in most 4-point or 3-point headgears. 
     The present invention keeps the minimum 2-point mounting attachment with the interface by introducing a dual force strapping connection to achieve maximum stability while minimizing the invasiveness of the respiratory interface device and associated headgear assembly. Accordingly, the invention is directed to a headgear with two (2) mounting points that provides four (4) connecting forces in distinctive upper (F x1 , F y1 ) and lower (F x2 , F y2 ) vectors. The result is a headgear with minimum contact providing maximum stability ideally for lower mounting interfaces focusing in the lower half of the face either with tip of the nose coverage or oral-nasal masks.  FIGS. 9 and 10 , respectively, show examples of the desired forces acting on a tip-of-the-nose device and an oral-nasal mask. The present invention contemplates that, the mounting angle θ of the upper attachment strap is between five (5) degrees (minimum) and forty (40) degrees (maximum) above the horizontal. 
     The primary limitation on the placement of the upper straps is the location of the corner of the eyes of a user. Mounting angle φ of the lower straps is between five (5) degrees (minimum) and twenty to twenty-five (20-25) degrees (maximum) below the horizontal. The minimum lower strap range is generally limited by the location of the ear lobes. Additionally, the maximum lower strap range is limited by the base of the neck, if the strap is too low on the neck this will be uncomfortable for patients, and possibly give the impression that the headgear is slipping down. It is to be appreciated that such angle ranges are given for example purposes only and that mounting angles outside of such ranges may be employed in certain applications. In such applications, it is desirable to attempt to maximize the mounting angle between the upper and lower attachment straps. 
       FIG. 1  shows a side view of a headgear assembly  10  according to an embodiment of the invention that is structured to adjustably retain a respiratory interface device  26  on a human head  8 . Headgear assembly  10  includes a headgear member  12  structured to fit over the crown and back portion of human head  8 . Headgear member  12  includes a pair of upper side portions  14  (only one shown in  FIG. 1 ) positioned on either side of head  8  generally above and forward of each ear and a pair of lower side portions  16  positioned generally along a back portion of head  8 . 
     In an exemplary embodiment, upper side portions  14  and lower side portions  16  are integrally formed with, and from the same material as headgear member  12 . According to an exemplary embodiment of the present invention, headgear member  12  is made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting or foam lamination. The present invention contemplates using multiple materials on one headgear such as a non stretchable foam lamination member  12  and stretchable fabric such as elastic band for retention members such as  20  and  30  as will be discussed below. Additionally, such materials may be breathable. 
     Continuing to refer to  FIG. 1 , headgear assembly  10  further includes a pair of strap-like upper retention members  20  (only one shown in  FIG. 1 ) and a pair of strap-like lower retention members  30  (only one shown in  FIG. 1 ). Each upper retention member  20  includes a first portion (not numbered) coupled to one of upper side portions  14  and a second portion  22  adjustably coupled to a clip member  23  of mask portion  24  of a respiratory interface device  26 , such that each upper retention member  20  extends generally downward and forward from a respective one of upper side portions  14  to mask portion  24 . Each lower retention member  30  includes a first portion (not numbered) coupled to one of lower side portions  16  and a second portion  32  adjustably coupled to clip member  23  such that each lower retention member  30  extends generally forward from a respective one of lower side portions  16  to mask portion  24 . The present invention contemplates that lower retention members  30  engages clip member  23  at or near the points of engagement of upper retention members  20 . 
     In the embodiment shown in  FIG. 1 , upper retention members  20  and lower retention members  30  are integrally formed with headgear member  12 . Additionally, the adjustable coupling of each upper retention member  20  and each lower retention member  30  to mask portion  24  may be accomplished through the use of a hook and loop fastening mechanism (as shown in  FIG. 1 ) or with other suitable means. 
     The present contemplates that each upper side portions  14  are stiffened, or reinforced, such as through inclusion of a reinforcement member  40  that is provided to each side of headgear member  12  and substantially overlaps each upper side portion  14 . Each reinforcement member  40  may be formed from a rigid or semi-rigid material such as, without limitation, silicone, polyurethane, or foam, which is not limited to fabric. It is to be appreciated that a wide variety of sewing techniques such as stitching and piping can be used to stiffen up the fabric or fabrics to create a frame without the need for inserting other materials. 
       FIG. 2  shows a side view of a headgear assembly  110  according to an another embodiment of the invention. Headgear assembly  110  includes a headgear member  112  structured to fit over the crown and back portion of human head  8 . Headgear member  112  may be made from any fabric such as previously described or similar thereto. However, due to the structural nature of the member, headgear member  112  may be made from a stiff, non-stretchable fabric. Headgear member  112  includes a pair of upper side portions  114  (only one shown in  FIG. 2 ) positioned on either side of head  8  generally above each ear and a pair of lower side portions  116  positioned generally along a back portion of head  8 . In an exemplary embodiment, upper side portions  114  and lower side portions  116  are integrally formed with, and from the same material as headgear member  112 . 
     Continuing to refer to  FIG. 2 , headgear assembly  110  further includes a pair of strap-like upper retention members  120  (only one shown in  FIG. 2 ) and a pair of strap-like lower retention members  130  (only one shown in  FIG. 2 ). Each upper retention member  120  includes a first portion  121  adjustably coupled to one of upper side portions  114  and a second portion  122  adjustably coupled to a mask portion  124  of a respiratory interface device  126  such that each upper retention member  120  extends generally downward and forward from a respective one of upper side portions  114  to mask portion  124 . Each lower retention member  130  includes a first portion (not numbered) coupled to one of lower side portions  116  and a second portion  132  adjustably coupled to mask portion  124  such that each lower retention member  130  extends generally forward from a respective one of lower side portions  116  to mask portion  124 . The present invention contemplates that lower retention members  130  engages mask portion  124  at or near the points of engagement of upper retention members  120 . 
     In the embodiment shown in  FIG. 2 , lower retention members  130  are integrally formed with headgear member  112 . Additionally, the adjustable couplings of each upper retention member  120  and each lower retention member  130  may be accomplished through the use of a hook and loop fastening mechanism (as shown in  FIG. 2 ) or with other suitable means. 
       FIG. 3  shows a side view of a headgear assembly  210  according to another embodiment of the invention. Headgear assembly  210  includes a headgear member  212  structured to fit over the crown and back portion of human head  8 . The present invention contemplates that headgear member  212  is made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting or foam lamination. It is common to use multiple materials on one headgear such as elastic band for retention members  220  and  230  as will be discussed below. Additionally, such materials may be breathable. Headgear member  212  includes a pair of upper side portions  214  (only one shown in  FIG. 3 ) positioned on either side of head  8 , generally above each ear, and a pair of lower side portions  216  positioned generally along a back portion of head  8 . 
     Continuing to refer to  FIG. 3 , headgear assembly  210  further includes a pair of upper retention members  220  (only one shown in  FIG. 3 ) and a pair of lower retention members  230  (only one shown in  FIG. 3 ). Each upper retention member  220  includes a first portion  221  adjustably coupled to one of upper side portions  214  and an opposite second portion  222  coupled to a mask portion  224  of respiratory interface device  226  such that each upper retention member  220  extends generally downward and forward from a respective one of upper side portions  214  to mask portion  224 . Each lower retention member  230  includes a first portion  231  adjustably coupled to one of lower side portions  216  and a second portion  232  coupled to mask portion  224  such that each lower retention member  230  extends generally forward and upward from a respective one of lower side portions  216  to mask portion  224 . Such adjustable couplings may be accomplished through the use of a hook and loop fastening mechanism  250  as shown generally in hidden line in  FIG. 3  or with other suitable means. 
     Each upper retention member  220  further includes an intermediate portion  223  that, in an exemplary embodiment, includes an elastic portion (e.g., without limitation, elastic straps). Similarly, each lower retention member  230  further includes an intermediate portion  233  that, in an exemplary embodiment, includes an elastic portion (e.g., without limitation, elastic strap). The present invention contemplates that such elastic portion may be formed of spandex polyester with an elongation in the range of 150-200%. 
     As further shown in the embodiment of  FIG. 3 , first portions  221 ,  231  of upper and lower retention members  220  and  230  are coupled together by transverse member  240 . Additionally, second portions  222 ,  232  are coupled together by mask engaging member  242  such that second portions  222 ,  232  generally engage mask portion  224  at a common location. 
       FIG. 4  shows a side view of a headgear assembly  310  according to an other embodiment of the invention that is structured to adjustably retain a respiratory interface device  326  on a human head  8 . Headgear assembly  310  includes a headgear member  312  structured to fit over the crown and back portion of human head  8 . Headgear member  312  includes a pair of upper side portions  314  (only one shown in  FIG. 4 ) positioned on either side of head  8 , generally above and forward of each ear, and a pair of lower side portions  316  positioned generally below and rearward from each ear along a back portion of head  8 . In an exemplary embodiment, upper side portions  314  and lower side portions  316  are integrally formed with, and from the same material as headgear member  312 . The present invention contemplates that headgear member  312  is made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting or foam lamination. Additionally, such materials are may be breathable. 
     Continuing to refer to  FIG. 4 , headgear assembly  310  further includes a pair of upper retention members  320  (only one shown in  FIG. 4 ) and a pair of lower retention members  330  (only one shown in  FIG. 4 ). In the embodiment of  FIG. 4 , upper retention member  320  and lower retention member  330  shown are separate portions of a unitary member  350  that, in an exemplary embodiment, is a cord-like member (e.g., without limitation, bungee cord, nylon cord). Unitary member  350  includes a first end portion  352  coupled to one of upper side portions  314 , an opposite second end portion  354  adjustably coupled to a corresponding one of the lower side portions  316 , and an intermediate portion  356  disposed between first end portion  352  and opposite second end portion  354 . Intermediate portion  356  is structured to slidably engage a portion  325  of mask portion  324 . As shown in  FIG. 4 , each upper retention member  320  extends generally downward and forward from a respective one of upper side portions  314  toward mask portion  324 . As further shown in  FIG. 4 , each lower retention member  330  extends generally forward and upward from a respective one of lower side portions  316  to mask portion  324 . 
     In order to provide stiffness to upper side portions  314 , a reinforcement member  340  is provided to each side of headgear member  312  substantially overlapping each upper side portion  314 . Each reinforcement member  340  is, in an exemplary embodiment, formed from a rigid or semi-rigid material such as, without limitation, silicone, polyurethane, or foam. It is to be appreciated that a wide variety of sewing techniques such as stitching and piping can be used to stiffen the fabric or fabrics to create a frame. Such techniques may be employed in conjunction with, or in lieu of, the reinforcement members  340 . 
       FIG. 5  shows a side view of a headgear assembly  410  according to another embodiment of the invention that is structured to adjustably retain a respiratory interface device  426  on a human head  8 . Headgear assembly  410  includes a headgear member  412  structured to fit over the crown and back portion of human head  8 . Headgear member  412  includes a pair of upper side portions  414  (only one shown in  FIG. 5 ) positioned on either side of head  8  generally above and forward of each ear and a pair of lower side portions  416  positioned generally below and rearward from each ear along a back portion of head  8 . In an exemplary embodiment, upper side portions  414  and lower side portions  416  are integrally formed with, and from the same material as headgear member  412 . Headgear member  412  is, in an exemplary embodiment, made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting or foam lamination. Such materials may be made breathable. 
     Continuing to refer to  FIG. 5 , headgear assembly  410  further includes a pair of upper retention members  420  (only one shown in  FIG. 5 ) and a pair of lower retention members  430  (only one shown in  FIG. 5 ). In the embodiment of  FIG. 5 , the upper retention member  420  and the lower retention member  430  shown are separate portions of a unitary member  450  that is, in an exemplary embodiment, a cord-like member (e.g., without limitation, bungee cord, nylon cord). Unitary member  450  includes a first end portion  452  coupled to one of upper side portions  414  at one of a number of locations  460  that provide for adjustment of the placement of the upper retention member  420  with respect to a user&#39;s eye. 
     Unitary member  450  further includes an opposite second end portion  454  adjustably coupled to a corresponding one of lower side portions  416  and an intermediate portion  456  disposed between first end portion  452  and opposite second end portion  454 . Intermediate portion  456  being structured to slidably engage a portion  425  of mask portion  424 . As shown in  FIG. 5 , each upper retention member  420  extends generally downward and forward from a respective one of upper side portions  414  toward mask portion  424 . As further shown in  FIG. 5 , each lower retention member  430  extends generally forward and upward from a respective one of lower side portions  416  to mask portion  424 . 
     In order to provide stiffness to upper side portions  414 , a reinforcement member  440  is provided to each side of headgear member  412  substantially overlapping each upper side portion  414 . Each reinforcement member  440  is, in an exemplary embodiment, made from a semi rigid polymer such as, without limitation EVA copolymer, polyethylene, polypropylene, polyurethane, vinyl, that is formed through injection molding or die cutting. 
       FIG. 6  shows a side view of a headgear assembly  510  according to an embodiment of the invention that is structured to adjustably retain a respiratory interface device  526  on a human head  8 . Headgear assembly  510  includes a headgear member  512  structured to fit over the crown and back portion of human head  8 . Headgear member  512  includes a pair of upper side portions  514  (only one shown in  FIG. 6 ) positioned on either side of head  8  generally above and forward of each ear and a pair of lower side portions  516  positioned generally below and rearward from each ear along a back portion of head  8 . In an exemplary embodiment, upper side portions  514  and lower side portions  516  are integrally formed with, and from the same material as headgear member  512 . Headgear member  512  is, in an exemplary embodiment, made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting, or foam lamination. Such materials may be breathable. 
     Continuing to refer to  FIG. 6 , headgear assembly  510  further includes a pair of upper retention members  520  (only one shown in  FIG. 6 ) and a pair of lower retention members  530  (only one shown in  FIG. 6 ). In the embodiment of  FIG. 6 , upper retention member  520  and lower retention member  530  shown are separate portions of a unitary member  550  that is, in an exemplary embodiment, a cord-like member (e.g., without limitation, bungee cord, nylon cord). Unitary member  550  includes a first end portion  552  coupled to one of upper side portions  514 , an opposite second end portion  554  adjustably coupled to a corresponding one of lower side portions  516 , and an intermediate portion  556  disposed between first end portion  552  and opposite second end portion  554 . Intermediate portion  556  being structured to slidably engage a portion  525  of mask portion  524 . As shown in  FIG. 6 , each upper retention member  520  extends generally downward and forward from a respective one of upper side portions  514  toward mask portion  524 . As further shown in  FIG. 6 , each lower retention member  530  extends generally forward and upward from a respective one of lower side portions  516  to mask portion  524 . 
     Headgear member  512  further includes a pair of secondary adjustment members  560  (only one shown in  FIG. 6 ). Each of secondary adjustment members  560  having a first end  562  coupled to one of upper side portions  514  and an opposite second end  564  adjustably coupled to a corresponding one of lower side portions  516 . In an embodiment, the opposite second end of each of secondary adjustment members  560  is further coupled to opposite second end  554  of unitary member  550 . It can be readily appreciated that such arrangement allows for rapid adjustment of headgear assembly  510  by tightening or loosening at two locations  570  (only one location shown in  FIG. 6 ). 
       FIG. 7  shows a side view of a headgear assembly  610  according to another embodiment of the invention that is structured to adjustably retain a respiratory interface device  626  on a human head  8 . Headgear assembly  610  includes a headgear member  612  structured to fit over the crown and back portion of human head  8 . Headgear member  612  includes a pair of upper side portions  614  (only one shown in  FIG. 7 ) positioned on either side of head  8  generally above each ear and a pair of lower side portions  616  positioned generally below each ear. In an exemplary embodiment, upper side portions  614  and lower side portions  616  are integrally formed with, and from the same material as headgear member  612 . Headgear member  612  is, in an exemplary embodiment, made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting or foam lamination. Such materials may be breathable. 
     Continuing to refer to  FIG. 7 , headgear assembly  610  further includes a pair of upper retention members  620  (only one shown in  FIG. 7 ), each depending from upper side portions  614 , and a pair of lower retention members  630  (only one shown in  FIG. 7 ) each generally extending forward and upward from lower side portions  616 . Each lower side portion  616 , in an exemplary embodiment, further includes an upward extending portion  670  that terminates at an adjustable portion  672  that engages a respective one of upper retention members  620  and may generally deflect upper retention member  620  away from the eye (not numbered) of a user. Such adjustable portion may include a hook and loop or other suitable fastener. 
     In the embodiment of  FIG. 7 , each one of the pair of upper retention members  620  and each one of the pair of lower retention members  630  are separate portions of a unitary member  650 . Unitary member  650  is, in an exemplary embodiment, a cord-like member (e.g., without limitation, bungee cord, nylon cord). Unitary member  650  is shown as a continuous loop having a portion  652  that is adjustably coupled to an upper rear portion  660  of headgear member  612 . Unitary member  650  may also be formed from a member having two ends (not shown), with the two ends being adjustable coupled to the upper rear portion  660 . Unitary member  650  slidably engages headgear member  612  at each of upper side portions  614  as well as at each of lower side portions  616 . Additionally, a portion  656  of unitary member  650  slidably engages a portion  625  of mask portion  624 . 
     It is to be appreciated that such arrangement allows for rapid adjustment of headgear assembly  610  by tightening or loosening unitary member  650  at one location  670 . Although  FIG. 7  shows unitary member  650  adjustably coupled to upper rear portion  660 , it can be readily appreciated that such adjustable coupling to headgear member  612  could be made substantially anywhere and still provide similar benefits. 
       FIG. 8  shows a side view of a headgear assembly  710  according to another embodiment of the invention that is structured to adjustably retain a respiratory interface device  726  on a human head  8 . Headgear assembly  710  includes a headgear member  712  structured to fit over the crown and back portion of human head  8 . Headgear member  712  includes a pair of upper side portions  714  (only one shown in  FIG. 8 ) positioned on either side of head  8  generally forward and above each ear and a pair of lower side portions  716  (only one shown in  FIG. 8 ) positioned generally below each ear. In an exemplary embodiment, upper side portions  714  and lower side portions  716  are integrally formed with, and from the same material as headgear member  712 . Headgear member  712 , in an exemplary embodiment, is made of either stretchable or non stretchable fabric, such as made from weaving, knitting, crocheting, knotting, felting or foam lamination. Such materials may be breathable. 
     Continuing to refer to  FIG. 8 , headgear assembly  710  further includes a pair of upper retention members  720  (only one shown in  FIG. 8 ) and a pair of lower retention members  730  (only one shown in  FIG. 8 ). In the embodiment of  FIG. 8 , upper retention member  720  and lower retention member  730  shown are separate portions of a unitary member  750  that are, in an exemplary embodiment, made from a cord-like member (e.g., without limitation, bungee cord, nylon cord). Unitary member  750  includes a first end portion  752  adjustably coupled to one of the upper side portions  714 , an opposite second end portion  754  adjustably coupled to a corresponding one of lower side portions  716 , and an intermediate portion  756  disposed between first end portion  752  and opposite second end portion  754 . Intermediate portion  756  being structured to slidably engage a portion  725  of mask portion  724 . As shown in  FIG. 8 , each upper retention member  720  extends generally downward and forward from a respective one of upper side portions  714  toward to portion  725 . As further shown in  FIG. 8 , each lower retention member  730  extends generally forward and upward from a respective one of lower side portions  716  to portion  725 . 
     It can be readily appreciated that such arrangement allows for rapid adjustment of headgear assembly  710  by tightening or loosening at two locations  770  (only one location shown in  FIG. 8 ). 
     While exemplary embodiments of the invention have been described and illustrated herein in conjunction with tip-of-the-nose respiratory interface devices, it is to be readily appreciated that the concepts disclosed herein may readily be applied to oral-nasal masks as well as to other mask assemblies. 
     Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.