A method of demonstrating difference in texture of skin

Abstract

The present invention relates to a method of demonstrating a difference in texture of a skin area using either participants' own skin or substrates that mimic the properties of human skin after use of a skin care product. More particularly, it relates to a method that utilizes changes in brain waves measured using electroencephalography as generated by the individual's nervous system on touching the treated skin area. The method can also be used for demonstrating the superiority of one product over another in delivering texture benefits to skin.

Description

[0001] P0000876 CPL

[0002] 1

[0003] A METHOD OF DEMONSTRATING DIFFERENCE IN TEXTURE OF SKIN

[0004] Field of the Invention

[0005] 5 The present invention relates to a method of demonstrating the difference in texture of a skin area after use of a skin care product. More particularly, it relates to a method that utilizes changes in brain activity measured using electroencephalography as generated by the individual’s nervous system on touching the treated skin area.

[0006] Background of the Invention

[0007] Skin is the largest external organ of the body and is the barrier between all internal organs and the environment. The primary function of the skin is to protect the body against changing environmental conditions like heat, cold, dust, wind and invading microorganisms like bacteria and viruses. The appearance of the skin is also affected through dermatological disorders and

[0008] 15 due to the above changing environmental factors. It also deteriorates in a consistent manner with aging (chronoaging). These may be accelerated by exposure of skin to sun (photoaging). The appearance and smoothness of skin can be improved though use of cosmetic products.

[0009] Consumers are increasingly using various cosmetic products which treat or delay the visible signs

[0010] 20 of chronoaging and photoaging skin such as wrinkles, lines, sagging, hyperpigmentation and age spots. Many of these signs are perceived visually but some can only be perceived by touch (i.e. by perceiving the change in texture of the skin). Further, they also use skin cleansing products that clean and disinfect the skin, in addition to sometimes depositing certain skin care actives on to skin which may alter the texture of skin. Current methods to demonstrate the beneficial effect

[0011] 25 of such personal care products in delivering these texture benefits include high resolution photography and consumer feedback. However, these measures are often indirect (e.g. photography), subjective (e.g. consumer feedback) or both.

[0012] The present inventors were working on a solution to this problem and found that methods of mapping the brain and correlating it with sensory feel of skin on touching has not been much explored. While some studies have been conducted to measure the brain activity on application of a cosmetic product and correlating it to subjective feedback given by the user, the present inventors are not aware of any method developed to demonstrate a difference in texture of a skin area after use of the product by touching it with a finger and visually representing the brain

[0013] 35 oscillatory changes. Measuring brain responses to touching skin after product use provides a direct and objective means to confirm the efficacy of a product in delivering skin texture benefits P0000876 CPL

[0014] 2 as sensed by the brain. With extensive experimentation that involved measuring brain waves using electroencephalography (EEG), they have arrived at the present invention which can unambiguously demonstrate the changes in cortical oscillatory activity to demonstrate skin texture benefits resulting from the use of a cosmetic product as sensed by the brain. They also found

[0015] 5 that this method can be used to show the superiority of one cosmetic product over another.

[0016] It is thus an object of the present invention to provide for a method of demonstrating the difference in texture of skin using brain imaging techniques.

[0017] Summary of the Invention

[0018] The first aspect of the present invention relates to a method of demonstrating a relative difference in texture between skin areas after use of a skin care product, the method comprising the steps of

[0019] (i) treating the skin area with a skin care product;

[0020] 15 (ii) waiting for a period of at least 5 minutes;

[0021] (iii) having a person touch the skin area using a finger;

[0022] (iv) measuring the cortical oscillatory activity using electroencephalography before touch and upon touch of the skin area;

[0023] (v) processing the data collected using a processing means; and

[0024] 20 (vi) statistically comparing the oscillatory activity measured in the different frequency bands.

[0025] The processing means may be an electronic processor / computer.

[0026] The brain oscillatory changes after use of the product may also be represented visually.

[0027] 25

[0028] A preferred aspect of the present invention relates to the method of the first aspect for demonstrating superiority of one cosmetic product over another.

[0029] Detailed Description of the Invention

[0030] The present invention relates to a method where the tactile sensation of difference in texture resulting from the use of a cosmetic product is objectively measured using a neuroscience approach. Thus, the present invention is aimed at using electroencephalography [EEG] to measure brain activity generated by the individual’s nervous system when touching skin to demonstrate changes in skin texture in relation to product functionality (i.e. sensory perception of

[0031] 35 skin texture). P0000876 CPL

[0032] 3

[0033] The present invention can also be used to measure difference in texture on any other surrogate substance that mimics skin. They have demonstrated this on artificial skin plates, which were used to simulate real skin. These were treated with the skin care product and offered an efficient

[0034] 5 means to measure brain activity generated by the individual’s nervous system when touching these plates to demonstrate changes in skin texture in relation to product functionality (i.e. sensory perception of skin texture).

[0035] The method may also be used to measure relative difference between different areas of the skin.

[0036] 10 After the product is applied to the skin, the measurement is made 5 minutes, preferably 15 minutes, more preferably 25 minutes after application. The treated skin area is then touched using one’s own finger. Alternatively, one person may touch the treated area of another person’s skin. The skin may be touched once or multiple times but generally not more than 120 times. The skin is touched at a controlled speed and for a set duration. The speed of stroking the skin

[0037] 15 may be in the range of 1 cm / s to 10 cm / s preferably in the range of 3 to 7 cm / s. The skin is preferably touched for a time duration in the range of 2 s to 120 s, more preferably in the range of 2 s to 20 s.

[0038] In the final step of the method, the oscillatory activity as measured in the different frequency

[0039] 20 bands are statistically compared. This is preferably done by comparing Event- Related Desynchronisation / Synchronisation in the alpha band.

[0040] When the method is used to measure the difference of one product over another, e.g. in demonstrating the superiority of one product over another, the two products may be applied on

[0041] 25 two different areas of the skin.

[0042] The method of the invention may be utilized to demonstrate the benefit of using a skin care product. The product may be of the leave on type or may be of the wash-off type.

[0043] 30 The method as per the invention is preferably non-therapeutic.

[0044] These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any

[0045] 35 other aspect of the invention. The word "comprising" is intended to mean "including" but not P0000876 CPL

[0046] 4 necessarily "consisting of" or "composed of." In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight / weight percentages unless otherwise indicated. Except in the operating

[0047] 5 and comparative examples, or where otherwise explicitly indicated, all numbers in this description and claims indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that

[0048] 10 all ranges combining the different endpoints are also contemplated.

[0049] The composition used in the method of the invention is meant to be used for skin care. The terms ‘personal care’ and ‘cosmetic care’ are used in the present specification to mean the same as ‘skin care’. Thus, a skin care composition, a personal care composition, and a cosmetic

[0050] 15 composition mean one and the same thing. The above mentioned compositions or products as used herein, is meant to include a composition for topical application, i.e .external surfaces of the skin and / or hair of humans. Such a composition may be classified as leave-on or wash off, and includes any product applied to a human body for improving appearance, cleansing, odour control or general aesthetics. The composition is preferably of the wash-off type. The composition of

[0051] 20 the present invention can be in the form of a liquid, lotion, cream, paste, powder, emulsion, foam, stick, roll-on, gel or through an aerosol containing composition. Preferred compositions include a cream, lotion, gel, paste, powder or emulsion.

[0052] "Skin" as used herein is meant to include skin on the face and body, e.g. neck, chest, back, arms,

[0053] 25 underarms, hands, legs and scalp.

[0054] Skin care compositions as per this invention may comprise a suitable active which delivers a benefit to skin. Such actives may be one or more of a PPAR acid, e.g. 12-hydroxystearic acid, water soluble vitamin, e.g. Niacinamide, fat soluble vitamin, alpha hydroxy acid, beta hydroxy

[0055] 30 acid, or a mixture thereof.

[0056] Leave-on compositions

[0057] The composition for use in the method of the invention may be delivered as a leave on composition. The cosmetically acceptable vehicle for a leave on composition is preferably in the

[0058] 35 form of an oil, liquid, stick, cream, lotion, spray or gel. The cosmetically acceptable vehicle in P0000876 CPL

[0059] 5 leave on compositions preferably includes ingredients like a non-ionic surfactant, a fatty acid, a soap, a polymer, an emollient, a polyhydric alcohol, a solvent, a powder or combinations thereof. Details on the various possible ingredients for inclusion in the cosmetically acceptable vehicle are given below.

[0060] 5

[0061] Preferably, the composition comprises a nonionic surfactant. Preferably, the nonionic surfactant is selected from fatty alcohol ethoxylates, alkyl phenol ethoxylates, polyoxyethylene sorbitan alkyl esters, and mixtures thereof. Preferably, the leave-on composition comprises 0.5 to 5 wt%, more preferably 1 to 4 wt%, even more preferably from 2 to 3 wt% nonionic surfactant having HLB in

[0062] 10 the range 9 to 20. Another preferred non-ionic surfactant is cocamide monoethanolamide (CMEA).

[0063] Preferably, the composition of the invention is delivered in the form of a vanishing cream. A vanishing cream is one which when applied and rubbed on to the human skin, vanishes on the

[0064] 15 skin leaving behind no significant streaks of the composition. Fatty acids when present in a composition along with a soap provides the so-called vanishing cream effect. Preferably, the leave-on composition comprises fatty acids having 10 to 30, more preferably 12 to 25, even more preferably 14 to 20, further more preferably 16 to 18 carbon atoms. Examples of fatty acids that may be used in the composition include pelargonic, lauric, myristic, palmitic, stearic, isostearic,

[0065] 20 oleic, linoleic, arachidic, behenic, erucic acid and mixtures thereof. Preferably, the fatty acid that may be used is stearic acid or palmitic acid or a mixture thereof. The fatty acid in the present invention is preferably hysteric acid which is substantially (generally about 90 to 95%) a mixture of stearic acid and palmitic acid in a ratio of between 55:45 to 45:55.

[0066] 25 Preferably, the vanishing cream composition comprises from 2.25 to 25 wt%, more preferably from 4 to 22 wt%, even more preferably from 6 to 20 wt%, further more preferably from 8 to 19 wt% and still more preferably from 10 to 18 wt% and yet more preferably from 12 to 16 wt% fatty acid.

[0067] 30 Preferably, the vanishing cream composition comprises soap. Soap, when present in combination with fatty acid in the composition, provides the vanishing effect described above. Preferably, soap in the composition is generally prepared by in-situ neutralization of fatty acid that may be present in the composition. Thus, it is preferred that the soap has a carbon chain length that corresponds to the chain length of fatty acid in the composition. The soap is formed from the

[0068] 35 fatty acid through use of alkali metal hydroxides, e.g. sodium hydroxide or potassium hydroxide. P0000876 CPL

[0069] 6

[0070] Of the two, potassium hydroxide is more preferred. Thus, the soap is preferably a potassium soap (potassium salt of fatty acid). Preferably, the vanishing cream composition comprises from 0.1 to 10 wt%, more preferably from 0.25% to 8 wt%, even more preferably from 0.5 to 7 wt%, further more preferably from 0.5 to 5 wt% soap, even further more preferably 0.5 to 3 wt%.

[0071] 5

[0072] Preferably, the leave on composition may comprise a polymer. The polymer acts as thickener in the composition and improves sensorial properties of the composition. The polymer is preferably selected from the following classes: acrylate I R-methacrylate copolymer e.g. acrylates / steareth-20 methacrylate copolymer

[0073] 10 (commercially available as Aculyn™ 22) and acrylates / beheneth-25 methacrylate copolymer (commercially available as Aculyn™ 28), acrylate I R-methacrylate crosspolymer e.g. acrylates / steareth-20 methacrylate crosspolymer (commercially available as Aculyn™ 88), acrylates copolymer (commercially available as Aculyn™ 33),

[0074] 15 acrylate / R-alkyl acrylate crosspolymer e.g. acrylates / C10-C30 alkyl acrylate crosspolymer (commercially available as Pemulen™ TR-2), copolymer of ammonium acryloyldimethyltaurate with vinyl pyrrolidone (commercially available as Aristoflex® AVC), copolymer of sodium acryloyldimethyltaurate with vinyl pyrrolidone (commercially

[0075] 20 available as Aristoflex® AVS); and crosspolymer of acryloyldimethyltaurate with R-alkyl acrylate and methyacrylate e.g.

[0076] Ammonium acryloyldimethyltaurate / beheneth-25 methacrylate crosspolymer (commercially available as Aristoflex® HMB and Aristoflex® BLV).

[0077] 25 Preferably, the composition comprises 0.1 to 5 wt%, more preferably 0.25 to 4.5 wt%, even more preferably 0.5 to 4 wt%, further more preferably from 0.75 to 3.5 wt%, still more preferably from 0.75 to 2.75 wt% polymer.

[0078] Preferably, the composition comprises emollients. Examples of emollients that may be used in

[0079] 30 the leave-on composition include stearyl alcohol, glyceryl monoricinoleate, mink oil, isopropyl isostearate, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecan-2-ol, isocetyl alcohol, eicosanyl alcohol, behenyl alcohol, cetyl palmitate, silicone oils such as dimethylpolysiloxane, din-butyl sebacate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, butyl stearate, polyethylene glycol, triethylene glycol, lanolin, cocoa

[0080] 35 butter, corn oil, cotton seed oil, olive oil, palm kernel oil, rape seed oil, safflower seed oil, evening P0000876 CPL

[0081] 7 primrose oil, soybean oil, sunflower seed oil, avocado oil, sesame seed oil, coconut oil, arachis oil, castor oil, acetylated lanolin alcohols, petroleum jelly, mineral oil, butyl myristate, isopropyl linoleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate, caprylyl triglyceride, and mixtures thereof.

[0082] 5

[0083] Preferably the composition may comprise a polyhydric alcohol. Polyhydric alcohols are selected from one or more of glycerol, propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1 ,3-butylene glycol, isoprene glycol, 1 ,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol, or a combination thereof. Most preferred is glycerol.

[0084] Preferably, the composition comprises solvents. Examples of solvents that may be used in the composition include ethyl alcohol, isopropanol, acetone, ethylene glycol ono ethyl ether, diethylene glycol mono butyl ether, diethylene glycol mono ethyl ether, and mixtures thereof.

[0085] 15

[0086] Preferably, the composition comprises powders. Examples of powders that may be used in the composition include zinc oxide, titanium oxide, chalk, talc, fullers earth, kaolin, starch, gums, colloidal silica sodium polyacrylate, tetra alkyl and / or trialkyl aryl ammonium smectites, chemically modified magnesium aluminium silicate, organically modified montmorillonite clay, hydrated

[0087] 20 aluminium silicate, fumed silica, carboxyvinyl polymer, sodium carboxymethyl cellulose, ethylene glycol monostearate, and mixtures thereof.

[0088] Water is present in different amounts depending on the type of leave on composition. Liquid composition may comprise from 40 to 90 wt% water. Creams, lotions and gels may comprise a

[0089] 25 smaller amount of water, for example in the range of 5 to 70 wt% water.

[0090] Preferably, the composition comprises a range of other optional ingredients that include antioxidants, binders, buffering agents, colorants, astringents, fragrance, opacifying agents, conditioners, exfoliating agents, pH adjusters, skin sensates, skin soothing agents, sunscreens, and skin healing agents.

[0091] Another type of leave-on skin-care composition which may be used for demonstrating the method the invention is an antiperspirant or deodorant.

[0092] 35 P0000876 CPL

[0093] 8

[0094] Wash-off compositions

[0095] The composition of the present invention may also be delivered through a wash-off composition which is used for the purpose of cleansing a surface, e.g. skin. The composition may then be applied on to the skin using suitable means, often using hands, and alternatively using a sponge,

[0096] 5 loofah or similar material along with copious amount of water to create lather; which is rinsed off with water to cleanse the surface, e.g. the skin. "Skin" as used herein is meant to include skin on the face and body e.g., neck, chest, back, arms, underarms, hands, legs and scalp.

[0097] The wash-off compositions of the invention preferably includes a cleansing surfactant. The cleaning surfactant may be one or more of an anionic surfactant, non-ionic or amphoteric surfactant. Anionic surfactant is generally included in 3.0 to 80 wt%, preferably 4.0 to 40 wt%, more preferably 4.0 to 20 wt%. When the wash off composition is in liquid form, it is preferred that the anionic surfactant is a soap, an isethionate, taurate, glycinate, glutamate, alkyl sulphate, a-olefin sulphonate, alkyl ether sulphate, succinate, sulphosuccinate, sarcosinate, amphoacetate,

[0098] 15 and mixtures thereof.

[0099] Preferably, the anionic surfactant is selected from soap, alkyl sulfates, alkyl ether sulfates, isethionate, taurate, and mixtures thereof. Even more preferably, alkyl ether sulfates are used as the anionic surfactant in the composition. Anionic surfactants are known to provide foam and

[0100] 20 cleansing action.

[0101] Examples of alkyl sulfates that may be used as anionic surfactant in the composition include sodium lauryl sulfate (SLS), sodium myristyl sulfate, and mixtures thereof.

[0102] 25 Examples of AES that may be used as anionic surfactant in the composition include sodium lauryl ether sulfate (SLES), sodium myristyl ether sulfate and sodium palmityl ether sulfate, and mixtures thereof. Preferred AES is SLES having 1 to 3 ethylene oxide units per molecule. SLES having 1 to 2 ethylene oxide units per molecule is more preferred.

[0103] 30 Another class of anionic surfactants which is particularly desirable are alkyl isethionate (e.g., fatty acid esters of isethionate acid such as sodium lauroyl or sodium cocoyl isethionate) and alkyl taurate (e.g., alkyl taurate amides such as N-methyl taurate). Especially suitable is to include them as a surfactant mixture as they have the advantage that they are sulfate-free. Further, they offer the ability to formulate isotropic systems at neutral and slightly acidic pH. P0000876 CPL

[0104] 9

[0105] As especially preferred aspect relates to compositions comprising 5 to 20%, preferably 6 to 15% by weight of a surfactant system which comprises (a) alkali metal acyl isethionate, (b) alkali metal alkyl taurate. Preferred isethionate sulfonates include cocoyl isethionate and lauroyl isethionate, preferably having sodium or potassium as counterions. The other preferred anionic surfactant

[0106] 5 for inclusion in the composition of the invention are alkyl taurates, e.g. alkyl taurate amides. Preferably alkyl taurate amides include sodium methyl cocoyl taurate and sodium methyl lauroyl taurate.

[0107] The composition may also be delivered with soap as the anionic surfactant or as a combination

[0108] 10 of one or more of the above mentioned synthetic anionic surfactant together with soap. Such combination of soap and synthetic anionic surfactants may be included in a cleansing composition in both liquid as well as in solid (e.g. a bar) compositions. The soap for preparing the cleansing composition of the invention is preferably a C8-C24 soap, more preferably C10-C20 soap and most preferably C12-C18 soap. The cation of the soap can be alkali metal, alkaline earth metal or

[0109] 15 ammonium. Preferably, the cation of the soap is selected from sodium, potassium or ammonium. More preferably the cation of the soap is sodium or potassium. Fatty acids derived from other suitable oils / fats such as groundnut, soybean, tallow, palm, palm kernel, etc. may also be used in other desired proportions. Such combination of soap with synthetic surfactants is often called a soap-syndet formulation. It is preferred that the skin cleansing composition of the invention

[0110] 20 comprises starch.

[0111] Preferably, the composition may further comprise an amphoteric surfactant. They provide foam boost and improve sensorial of the composition. Preferably, amphoteric surfactants are selected from the class of betaines, sultaines, ethanolamides. Preferred examples are cocamidopropyl

[0112] 25 betaine (CAPB), cocoamphoacetate, and mixtures thereof. When included the composition preferably comprises from 0.1 to 40 wt%, more preferably 1 to 20 wt%, most preferably from 1 to 5 wt% amphoteric surfactant.

[0113] Non-ionic surfactants may also be included in the wash-off compositions as per the invention.

[0114] 30 Suitable non-ionic surfactants are the same as those described under the leave-on composition section above.

[0115] The pH of the composition is preferably in the range of 4.0 to 10.5, more preferably 4.0 to 9.0. pH as reported in the present invention is measured as follows: the composition is diluted 1 :1 with

[0116] 35 deionized water and pH is directly measured by a standard pH meter at room temperature (25°C). P0000876 CPL

[0117] 10

[0118] The composition of the invention when in the liquid form preferably comprises 5 to 95 wt%, more preferably in 40 to 90 wt% water.

[0119] 5 Preferably, the composition further comprises water soluble / dispersible polymers. They are known to increase the viscosity and stability of liquid cleansing compositions, to enhance in-use and after-use skin sensory feels, and to enhance lather creaminess and lather stability. Such polymers may preferably be used in amounts from 0.1 to 10 wt%, more preferably from 0.1 to 5 wt%.

[0120] Examples of water soluble / or dispersible polymers include the carbohydrate gums such as cellulose gum, microcrystalline cellulose, cellulose gel, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, sodium carboxymethylcellulose, methyl cellulose, ethyl cellulose, guar gum, gum karaya, gum tragacanth, gum arabic, gum acacia, gum agar, xanthan

[0121] 15 gum and mixtures thereof; modified and nonmodified starch granules and pregelatinized cold water soluble starch; emulsion polymers such as Aculyn® 28, Aculyn® 22 or Carbopol® Aqua SF1 ; cationic polymer such as modified polysaccharides including cationic guar available from Rhone Poulenc under the trade name Jaguar® C13S, Jaguar® C14S, Jaguar® C17, or Jaguar® C16; cationic modified cellulose such as LICARE® Polymer JR 30 or JR 40 from Amerchol; N-Hance®

[0122] 20 3000, N-Hance® 3196, N-Hance® GPX 215 or N-Hance® GPX 196 from Hercules; synthetic cationic polymer such as Merquat® 100, Merquat® 280, Merquat® 281 and Merquat® 550 sold by Nalco; cationic starches such as StaLok® 100, 200, 300 and 400 sold by Staley Inc.; cationic galactomannans such as Galactasol® 800 series by Henkel, Inc.; Quadrosoft® LM-200; and Polyquaternium-24®. Also suitable are high molecular weight polyethylene glycols such as

[0123] 25 Polyox® WSR-205 (PEG 14M), Polyox® WSR-N-60K (PEG 45), and Polyox® WSR-301 (PEG 90M).

[0124] The composition may further comprise emollients. Emollients listed above for use in leave-on compositions may be in wash-off compositions also.

[0125] 30

[0126] The compositions may further comprise a wide range of other optional components, e.g. antioxidants, biological additives, buffering agents, colorants, astringents, fragrance, humectants, opacifying agents, conditioners, pH adjusters, skin soothing agents and skin healing agents. P0000876 CPL

[0127] 11

[0128] The composition may also be delivered in solid form in which case it is preferably in the form of a bar. In such cases soap bars are preferred. Soap bars generally have the following constitution. Soap, i.e. salt of fatty acid is preferably present in an amount of 5 to 80%, preferably from 10 to 75%, more preferably 25 to 75% by weight of the cleansing composition. It may comprise small

[0129] 5 amount (0.1 to 10 wt%) of synthetic anionic surfactants which could be one or more of the ones listed herein above. The soap bars may include other known ingredients such as perfumes, pigments, preservatives, emollients, gelling agents and thickening agents. Choice of these ingredients will largely depend on the format of the composition. Water is a preferred carrier. When water is present, it is preferably present in at least 1 %, more preferably at least 2%, further more preferably at least 5% by weight of the composition. When water is the carrier, the soap bar may comprises 10 to 50%, more preferably 12 to 40%, further more preferably from 12 to 35% by weight water.

[0130] The cleansing composition of the invention may also be delivered through a moisturizing bar

[0131] 15 composition. Moisturizing bar compositions comprising fatty acyl isethionates (e.g. cocyl isethionate) are especially preferred. Fatty acyl isethionates (e.g., cocoyl isethionates) surfactant "products" are defined as mixtures of anionic acyl isethionate surfactants and fatty acids / fatty acid soaps. They are highly desirable in personal skin or hair cleansing products because they lather well, are mild to the skin and have good emollient properties. Typically, fatty acid isethionate

[0132] 20 surfactant products are produced by esterification of fatty acids or by reaction of fatty acid chloride having carbon chain length of C8 to C20 with isethionate. A typical surfactant product containing fatty acyl isethionate contains about 40 to 95 wt.% acid isethionate, and 5 to 50 wt.%, typically 10 to 40 wt.% free fatty acid, in addition to isethionate salts, typically at less than 5 wt%, and trace (less than 2 wt.%) of other additives. Fatty acid soap may be included in the range of 5 to 15 wt%.

[0133] 25 Other surfactants like betaines may be included in 1 to 5 wt%. Water is generally included in 2 to 8 wt% of the composition.

[0134] The composition of the invention may also be delivered through a self-foaming composition. A preferred self-foaming composition comprises 2.5 to 10 wt% surfactant which is usually a mixture of anionic surfactant and amphoteric surfactant. Anionic surfactants preferred are of the amino acid class viz. sodium lauroyl glycinate, sodium cocoyl glycinate, sodium lauroyl glutamate, sodium cocoyl glutamate and may also be selected from one or more of sodium lauroyl isethionate, sodium cocoyl isethionate, alpha olefin sulfonate (AOS), or a combination thereof. The amphoteric surfactant may be one or more as listed herein above. Self-foaming compositions

[0135] 35 additionally usually comprise a humectant selected from glycerol, propylene glycol, dipropylene P0000876 CPL

[0136] 12 glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1 ,3-butylene glycol, isoprene glycol, 1 ,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol, or a combination thereof. They may also comprise an emollient which may be selected from one or more of the compounds listed herein above. Such types of self-foaming compositions

[0137] 5 are usually free of sulphate.

[0138] Brief Description of the Figures:

[0139] Figure 1 : depicts the EEG results in a self-touch study where the brain perceives the difference between soft and draggy conditions of the skin.

[0140] In Figure 1 the EEG results for touching own skin during active texture exploration (1 - 7 s) in Theta (A), Alpha (B), and Beta (C) are depicted. Bar charts display the differences in ERD between the two conditions across all clusters and frequency bands. Error bars represent standard error. P = Percentage change from baseline. Statistically significant differences are

[0141] 15 denoted as * for p < .05, with a solid line representing significance when using two-tailed tests, and a dotted line denoting significance when using one-tailed tests. D displays the electrode locations for each cluster.

[0142] Figure 2. depicts the EEG results in an artificial skin plates study where the brain perceives the

[0143] 20 difference between soft and draggy conditions of the skin.

[0144] In Figure 2, the EEG results for touching artificial skin plates showing band power changes in both the Soft and Draggy Conditions during active texture exploration (1 - 5 s) in Theta (A), Alpha (B), and Beta (C) are depicted. Bar charts display the differences in ERD in all selected cluster

[0145] 25 locations between the Soft and Draggy Condition for all three frequency bands. Error bars represent standard error. P = Percentage change from baseline. Statistically significant differences are denoted as * for p < .05. D displays the electrode locations for Theta (A). E display the electrode locations for Alpha (B) and Beta (C).

[0146] 30 The invention will now be illustrated with the help of the following non-limiting example. P0000876 CPL

[0147] 13

[0148] Examples

[0149] Example 1. Touching one’s own skin

[0150] In the study the active exploration of one’s own skin during stroking of one’s own forearm was

[0151] 5 investigated. In the experiments, the substrates (one’s own skin) was treated with 2 different commercially available bar soaps, which were expected to deliver either a soft ('Soft Condition’) or more rough and draggy skin-feel (‘Draggy Condition’), respectively. Oscillatory activity was measured during the self-touch paradigm using a 129-channel EEG system.

[0152] 10 Thirty-one participants were recruited and changes in oscillatory band power using the Event- Related Desynchronisation / Synchronisation (ERD / ERS) method were evaluated in theta (4 - 7 Hz), alpha (8 - 12Hz), and beta (16 - 24 Hz) frequency bands during active touch exploration periods.

[0153] 15 Experimental procedure:

[0154] Following the marking of the test site on the participant’s arm, each soap treatment was prewetted. The application site was prepared by pre-wetting the area with running water. The treatment was applied onto the one side of forearm (the second treatment was applied to opposite side for the second block) using the corner of the soap. Water was applied to the test site and

[0155] 20 the area was lathered. The test site was then rinsed with running water. Following the rinsing period, the test site was gently blotted with a commercially available kitchen towel to remove water from the skin and the arm was left to dry for approximately 25 minutes. Before the onset of the task, the lines on the participant’s arm were redrawn (where required).

[0156] 25 The participants were first made to complete practice trials where they were trained on the pace of exploration during the task (5 cm / s). At the beginning of the training procedure, a 4-second countdown began and then the participant stroked their arm with the distal phalanx of their right index finger for 8 seconds along the marked section at a speed of 5 cm per second. Participants were instructed to complete four strokes of the exploration zone during this time. Accurate pacing

[0157] 30 was achieved using auditory cues and was supervised by the researcher who ensured the correct pace had been achieved. During the task, participants explored the treated zone at a pace of 5 cm / s. Each trial consisted of a baseline period (4 seconds) and an exploration period (8 seconds) followed by a response period.

[0158] 35 P0000876 CPL

[0159] 14

[0160] EEG Acquisition

[0161] For the studies, continuous EEG recordings were acquired using a 129-channel EGI System (Electrical Geodesic Inc., EGI, Magstim EGI, Eugene, Oregon, USA) and a sponge-based Geodesic Sensor net. The net positioning was aligned to three anatomic landmarks: two pre-

[0162] 5 auricular points and the nasion. Electrode-to-skin impedances were maintained below 50 kW throughout the experiment. The sampling rate was set at 1000 Hz and a recording bandpass filter was applied between 0.001 and 200 Hz. Electrode Cz was used as the reference.

[0163] EEG pre-processing and Analysis

[0164] EEG data from the studies were pre-processed using the Harvard Automated Processing Pipeline for Electroencephalography. The data were filtered between 0.5 Hz and 100 Hz using high- and low-pass filters, respectively. Line noise at 50 Hz was then removed using CleanLine, and the data was resampled to 250 Hz. Subsequently, bad channels were identified and interpolated, with the remaining data undergoing artefact correction using wavelet thresholding. The data were

[0165] 15 then segmented into epochs. A period of -4 seconds to 10 seconds was selected for the selftouch experiment. Channels within epochs that contained remaining excessive noise were interpolated and unusable epochs were rejected using the automated rejection process. Epochs were marked for rejection based on segment similarity and segment amplitude (set at -150 to 150 mV). Following trial rejection, the data were re-referenced using an average reference.

[0166] 20

[0167] Spectral analysis was conducted using MATLAB 2020B (The MathWorks, Inc., Natick, Massachusetts, USA) and EEGLAB 2022.0 (Delorme & Makeig, 2004). The power spectral density (PSD) was estimated using Welch’s method and was calculated from the EEG data from -4 seconds to 9 seconds relative to stimulus onset for the self-touch experiment. The power

[0168] 25 spectra were computed in 1 -second segments shifted in overlapping 0.1 -second steps. Timefrequency analysis was conducted using the multi-taper method, consisting of three tapers. The estimate of the PSD was computed between 1 and 80 Hz, with a frequency resolution of 1 Hz. The baseline period used for the analysis was -3.5 seconds to -0.5 seconds relative to stimulus onset. Relative band power changes were calculated in canonical frequency bands: Theta (4 -

[0169] 30 7 Hz), Alpha (8 - 12 Hz), and Beta (16 - 24 Hz) for each of the treatment conditions using the event-related desynchronisation (ERD) method. P0000876 CPL

[0170] 15

[0171] The estimate of the ERD for each datapoint (i.e. A in the above equation) is computed by subtracting the mean of the PSD during the baseline period (i.e. R in the above question). Subsequently, a numerical transform is conducted to obtain the relative change in power as a percentage value. Negative ERD values represent a decrease in band power during the active

[0172] 5 period, relative to baseline, and indicate cortical activation. Positive values reflect band power increases during the active period, relative to the baseline period and are indicative of cortical inhibition, which is known as event-related synchronisation (ERS).

[0173] For the analysis, time windows that encompassed the active texture exploration were chosen.

[0174] 10 For the present study, 1 second to 7 seconds relative to stimulus onset was selected. These time windows represent the period of active exploration and omitted both movement onset (<1 second) and cessation ( >7 seconds in the self-touch study). Movement onset and cessation can have unique ERD profiles and were omitted in line with previous research to reduce confounding effects of touch initiation / cessation. Grand average topographies were generated and used to identify

[0175] 15 scalp regions demonstrating peak changes in ERD for touch exploration in each paradigm, and in each frequency band of interest to select relevant clusters of electrodes for statistical analysis for the self-touch study.

[0176] Following the identification of the clusters, outliers were removed for each frequency band and

[0177] 20 experiment using the “rmoutliers” function in MATLAB, which removes values exceeding three scaled median absolute deviations from the median. Subsequently, paired sample t-tests were conducted to identify whether ERD / S differed between the skin treatment conditions. Significant clusters were then correlated with significant behavioural outcomes.

[0178] 25 Results

[0179] The ERD results for the self touch study is visually represented in Fig. 1. A summary of the observations is as give below.

[0180] Alpha

[0181] 30 In the Alpha frequency band, there were no significant differences between Draggy and Soft Condition in the fronto-central cluster (t (25) = 1.84, p = .077, d = .361), left frontal cluster (t (25) = 1.73, p = .097, d = .338), right frontal cluster (t (25) = 1.63, p = .115, d = .321), left central- parietal cluster (t (25) = 1.55, p = .134, d = .304), right central-parietal cluster (t (25) = 1.94, p = .064, d = .381), or the parieto-occipital cluster (t (25) = 1.24, p = .226, d = .244). However, the

[0182] 35 fronto-central (p = .039), left frontal (p = .048), and right central-parietal (p = .032) clusters were P0000876 CPL

[0183] 16 significant when using one-tailed p-values to investigate the directional effects with greater ERD observed in the Draggy compared to the Soft Condition for all significant cluster locations.

[0184] Beta

[0185] 5 The Draggy Condition elicited greater ERD in the Beta band compared to the Soft Condition in the right central-parietal cluster (t (22) = 2.18, p = .040, d = .455). There was no significant difference between the Draggy Condition and the Soft Condition in the fronto-central cluster (t (22) = 0.05, p = .957, d = .011), left (t (22) = 0.93, p = .365, d = .193) or right frontal clusters (t (22) = 0.35, p = .731 , d = .073), left central-parietal cluster (t (22) = 1.24, p = .228, d = .259), or

[0186] 10 the parieto-occipital central cluster (t (22) = 2.04, p = .053, d = .425). The parieto-occipital cluster was significant (p = .027) when using one-tailed p-values, with greater ERD observed in the Draggy Condition.

[0187] Theta

[0188] 15 The results demonstrated that ERD in the Theta band was significantly greater in the Draggy Condition compared to the Soft Condition in both the right frontal (t (28) = 2.11 , p = .044, d = .392) and right central-parietal clusters (t (28) = 2.41 , p = .023, d = .447). No significant difference was observed between the two conditions for the fronto-central cluster (t (28) = 1.85, p = .074, d = .344), left frontal cluster (t (28) = 1.53, p = .138, d = .284), left central-parietal cluster (t (28) =

[0189] 20 1.68, p = .105, d = .311), or the parieto-occipital central cluster (t (28) = 1.25, p = .220, d = .233). However, the fronto-central cluster demonstrated a significant between Draggy Condition and the Soft Condition (p = .037), with the Draggy Condition eliciting greater ERD than the Soft Condition when using one-tailed p-values.

[0190] 25 Given that ERD was consistently greater in the Draggy Condition compared to the Soft Condition an assessment was made whether the average across all clusters was significantly different between the two conditions. Outliers were removed using the same procedure as previous analyses to leave 30 participants for comparison. The results demonstrated that Theta band ERD was significantly greater in the Draggy Condition (M = -41.86, SD = 13.05) compared to the Soft

[0191] 30 Condition (M = -36.47, SD = 13.12; (t (28) = 2.30, p = .029, d = .427). This difference was also observed in the Alpha frequency band, with the Draggy Condition (M = -35.83, SD = 12.27) eliciting greater ERD than the Soft Condition (M = -30.84, SD = 16.57; t (29) = 2.31 , p = .028, d =.422). However, there was no significant difference between the Draggy Condition (M = -25.61 , SD = 7.33) and the Soft Condition (M = -22.66, SD = 11.11) in the Beta band (t (27) = 1.89, p =

[0192] 35 .070, d = .357). P0000876 CPL

[0193] 17

[0194] With the above experiment, it has been shown that the perception of difference in texture of a skin area after use of a skin care product by a person can be measured objectively using cortical oscillatory activity in the brain using electroencephalography.

[0195] 5

[0196] Example 2. Touching artificial skin plates

[0197] In the study the active exploration of artificial skin plates was investigated. In the experiments, the substrates (artificial skin plates) were treated with 2 different commercially available bar soaps, which were expected to deliver either a soft ('Soft Condition’) or more rough and draggy skin-feel (‘Draggy Condition’), respectively. Oscillatory activity was measured during the selftouch paradigm using a 129-channel EEG system.

[0198] Thirty-one participants were recruited and changes in oscillatory band power using the Event- Related Desynchronisation / Synchronisation (ERD / ERS) method were evaluated in theta (4 - 7

[0199] 15 Hz), alpha (8 - 12Hz), and beta (16 - 24 Hz) frequency bands during active touch exploration periods.

[0200] Artificial Skin Plates

[0201] For the artificial skin paradigm, medical prosthetic muscular tissue plates (SynDaver, Tampa, FL)

[0202] 20 measuring 200mm x 200mm were used. The muscular tissue plate consists of synthetic adult skin, subcutaneous fat, and skeletal muscle. The muscular tissue plate layers were comprised of 5mm of skeletal muscle, 5mm of subcutaneous fat, and 1 mm of skin, whilst the artificial skin toughness (penetration force) was 2 Newtons, designed to be representative of adult skin, skin colour was representative of Caucasian. Each treatment was associated with a specific skin plate

[0203] 25 which prevented cross-contamination. A total of four skin plates were used (two sets of two) throughout the study.

[0204] Artificial Skin Treatment Protocol

[0205] The artificial skin plates were prepared and treated before the arrival of the participants. Both

[0206] 30 skin plates were treated separately to prevent cross-contamination. Each artificial skin plate was removed from the storage solution and rinsed with water. It was dabbed dry with commercially available kitchen towel and then clean water was applied and rubbed into the skin plate. The soap treatment was wetted using tap water. The treatment was applied to the skin plate using the corner of the soap bar. Additional water was applied to the artificial skin and the solution was P0000876 CPL

[0207] 18 rubbed into the skin. The artificial skin plate was rinsed with running water and subsequently dabbed with a commercially available kitchen towel until dry.

[0208] Experimental Procedure

[0209] 5 The skin plate was mounted to the force plate and participants were instructed to sit in a comfortable position with their right hand over the force plate. An arm support, which supported and stabilised the forearm while maintaining the correct position of the hand over the sensor, was used. During verbal instructions, participants were informed that they would be exploring textures (i.e., skin plates) that had been treated with different products. During the task, participants

[0210] 10 explored the textures with the distal phalanx of their right index finger. Each trial consisted of a baseline period (4 seconds) and a tactile exploration (6 seconds) followed by a response period. Six practice trials were completed before beginning the tactile exploration task.

[0211] Each treatment condition (Soft and Draggy) was presented twice in a counterbalanced block

[0212] 15 design. There was a total of four blocks each lasting approximately 10 minutes. There was a total of 240 trials across four blocks (60 trials per block) with a short break between blocks to increase task engagement and reduce desensitisation. After each block, the participant’s exploration finger was wiped with a damp cloth to remove residual soap and avoid crosscontamination.

[0213] 20

[0214] The baseline period was indicated by a white cross on the screen, during which participants kept their finger stationary on the force plate. During the exploration period, a green fixation cross appeared indicating participants should start exploring the texture. Participants were instructed that they were free to explore the texture however they wished, i.e. multi-directional movements,

[0215] 25 changes to speed and force exerted. Exploration stopped when the green cross was removed from the screen which indicated the start of the response period.

[0216] EEG Acquisition

[0217] The EEG Acquisition was done using the same system and procedure as in Example 1.

[0218] 30

[0219] EEG pre-processing and Analysis

[0220] The EEG pre-processing and analysis was carried out using the same procedure as for Example 1 except that a period of -4 seconds to 8 seconds relative to the trial onset was selected for this study. Further for this study, 1 second to 5 seconds relative to stimulus onset was selected.

[0221] 35 P0000876 CPL

[0222] 19

[0223] Results

[0224] The ERD results for the artificial skin plates study are visually represented in Fig. 2. A summary of the observations is as give below.

[0225] 5 Alpha

[0226] In the alpha band, the results demonstrated that the Draggy Condition elicited greater ERD than the Soft Condition in both the left (Soft Mean = -27.23, Soft SD = 23.33; Draggy Mean = -32.48, Draggy SD = 20.17; t (26) = 2.12, p = .043, d = .409) and right central clusters (Soft Mean = - 31.50, Soft SD = 18.20; Draggy Mean = -35.92, Draggy SD = 21.83; t (26) = 2.06, p < .05, d = .396). There were no significant differences between Draggy and the Soft Condition in the fronto- central (Soft Mean = -15.60, Soft SD = 13.60; Draggy Mean = -18.31 , Draggy SD = 13.25; t (26) = 1.64, p = .113, d = .316), left posterior parietal (Soft Mean = -23.31 Soft SD = 20.01 ; Draggy Mean = -25.36, Draggy SD = 20.88; t (26) = 0.85, p = .404, d = .163), or right posterior parietal clusters (Soft Mean = -21.13, Soft SD = 19.01 ; Draggy Mean = -23.99, Draggy SD = 21.76; t (26)

[0227] 15 = 1.03, p = .312, d = .198).

[0228] Beta

[0229] In the beta band, the results demonstrated that the Draggy Condition elicited greater ERD than the Soft Condition in the left central cluster (t (26) = 2.13, p = .043, d= .410). No further significant

[0230] 20 differences between the Draggy and the Soft Condition were observed in the beta band for any clusters: fronto-central cluster (t (26) = 1.14, p = .265, d = .219), right central cluster (t (26) = 1.91 , p = .067, d = .368), left posterior parietal cluster (f (26) = 0.73, p = .475, d = .140), right posterior parietal cluster (t (26) = 1.28, p = .210, d = .247).

[0231] 25 Theta

[0232] No significant difference in theta band activity was observed between the Soft Condition and the Draggy Condition for the left central cluster (t (26) = 0.39, p = .698, d = .076), right central cluster (t (26) = 0.18, p = .858, d = .035), left centro-parietal cluster (t (26) = 0.37, p = .713, d = .071), or right centro-parietal cluster (t (26) = 1.44, p = .161 , d = .278).

[0233] 30

[0234] With the above experiment, it has been shown that the perception of differences in texture of an artificial skin plate after treatment with a skin care product by a person can be measured objectively using cortical oscillatory activity in the brain using electroencephalography.

Claims

P0000876 CPL20Claims1 . A method of demonstrating a relative difference in texture between skin areas after use of a skin care product, the method comprising the steps of(i) treating the skin area with a skin care product;(ii) waiting for a period of at least 5 minutes;(iii) having a person touch the skin area using a finger;(iv) measuring the cortical oscillatory activity using electroencephalography before touch and upon touch of the skin area;(v) processing the data collected using a processing means; and(vi) statistically comparing the oscillatory activity measured in the different frequency bands.

2. A method as claimed in claim 1 wherein the skin care product is a leave-on composition.

3. A method as claimed in claim 2 wherein the skin care product is an antiperspirant or deodorant.

4. A method as claimed in claim 1 wherein the skin care product is a cleansing composition.

5. A method as claimed in claims 4 wherein the cleansing composition is a soap bar.

6. A method as claimed in claim 5 wherein the soap bar comprises starch.

7. A method as claimed in any one of the preceding claims wherein the skin care product comprises a PPAR acid, water soluble vitamin, fat soluble vitamin, alpha hydroxy acid, beta hydroxy acid or a mixture thereof.

8. A method as claimed in any one of the preceding claims wherein the skin care product comprises a surfactant.

9. A method as claimed in any one of the preceding claims for demonstrating the superiority of a product in delivering skin texture benefits over another product.P0000876 CPL2110. A method as claimed in any one of the preceding claims wherein the skin is an artificial skin plate.

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