Seed oil on the performance of hand and finger motor skills in healthy subjects: A randomized controlled preliminary study
Steven Gorin Charles Wakeford Guodong Zhang Elvira Sukamtoh Charles Joseph Matteliano Alfred Earl Finch
Miracle fruit (Synsepalum dulcificum) seed oil (MFSO) contains phytochemicals and nutrients reported to affect musculoskeletal performance. The purpose of this study was to assess the safety and efficacy of a compression wristband containing MFSO on its ability to measurably improve the hand and finger motor skills of participants. Healthy right‐handed participants (n = 38) were randomized in this double‐blind, placebo‐controlled study of MFSO and vehicle wristbands. Subjects wore the wristband on their left hand 4–6 weeks and then only on their right hand 2–4 weeks; the contralateral untreated hand served as an additional control. Twelve hand/finger motor skills were measured using quantitative bio‐instrumentation tests, and subject self‐assessment questionnaires were conducted. With each hand, in 9/12 tests, the MFSO group showed a clinically meaningful average improvement compared with an average worsening in the vehicle group. Statistical superiority to the control treatment group was exhibited in 9/12 tests for each hand (p < .01). After discontinuing the MFSO wristband on the left hand, test values regressed toward baseline levels. Subjects favored the MFSO wristband over the control, rating it as effective in improving their motor skills. Use of the MFSO wristband may improve an individual's manual dexterity skills and ability to maintain this performance.
INTRODUCTION
Vegetable oils from plants and fruit seeds have been used for cosmetic and medicinal purposes as part of human culture for millennia. Synsepalum dulcificum seed oil, commonly known as miracle fruit seed oil (MFSO), is a rare and exotic fruit oil derived from the seed of the miracle fruit berry. The MFSO is an abundant source of phytochemicals and essential nutrients that are known to regulate the physiologic functions of cells. At greater than 20% of its weight, the bioactive‐rich unsaponifiable lipid fraction of the MFSO is among the highest in content recorded for a crude fruit seed oil. This fraction contains a substantial amount of phytochemicals such as the polyphenols, triterpenes, and phytosterols that exhibit antiinflammatory, antioxidant, and regenerative activities and appear to be beneficial for enhancing physical performance. Appreciable quantities of essential nutrients are also present within the MFSO such as linoleic acid, vitamin K, and elemental silicon that can affect locomotor activity and musculoskeletal health and homeostasis. During pilot studies to determine the safety and potential benefits of MFSO on improving the attributes of hair and alleviating skin conditions involving the hands, a number of subjects anecdotally described their hands and fingers feeling more nimble. When bioactive substances, such as vitamin E, are incorporated into the gels, their efficacy is enhanced possibly due to the occlusion that occurs with the application of modest pressures through compression that has been shown to provide a simple noninvasive method to enhance the skin permeability of substances. Elastomer gels have also been incorporated into wearables, such as sleeves and gloves, for orthopedic use to provide musculoskeletal support. In sports medicine, wearable compression garments that provide mechanical support have been utilized to improve physical performance.
Commercial equipment is routinely used to accurately measure grip and finger pinch strength with fatigue. The objective of this preliminary clinical study was to assess the safety and efficacy of MFSO combined with compression on its ability to measurably improve the physical performance skills of the hands and fingers of healthy right‐handed subjects. To achieve this objective, a novel wearable compression wristband was developed that would contain the MFSO within a flexible elastomeric gel.
MATERIALS AND METHODS
Participants
Main criteria for inclusion were (a) age range 21–66 years; (b) healthy volunteers; (c) written informed consent; (d) confirmed as right‐handed by responses to the Edinburg Handedness Inventory survey form; (e) right hand performing significantly better than the left hand on more than half of the tests, as assessed with the motor skills tests used for this study [percent (%) difference calculation]; and (f) willing to not significantly change their normal daily physical routines during the study. Among the exclusion criteria were (a) any musculoskeletal upper extremity symptom or condition in the past year; (b) use of any medicine or treatment that may significantly affect the study outcome in the past 3 months; (c) a history of any medical or surgical event or condition that may significantly affect the study outcome, including cardiovascular disease, metabolic, renal, hepatic, or musculoskeletal disorders; (d) use of any new upper extremity training methods during the study; (e) use of any new drugs or performance enhancing products during the study; (f) use of caffeine, tea, energy drinks, or supplements during the 48 hr before each study visit; (g) use of any other upper extremity wearable product during the study; and (h) participation in another clinical trial or the use of an investigational product in the past 60 days. All clinical study procedures were approved by the Aspire Institutional Review Board (reference number PRO007) for the protection of human subjects. Before any study procedures were performed, the experimental procedures and risks/benefits were discussed with the subjects, and written informed consent was obtained.
Study design and testing protocol
The preliminary study was conducted as a double‐blind, placebo‐controlled clinical trial. Participants were evaluated by staff on four visits during the study; at an initial screening visit (Visit 1), at baseline/pretreatment (Visit 2), after 4–6 weeks of treatment (Visit 3), and after 6–10 weeks of treatment at the end of the study (Visit 4).
Investigational product
The Synsepalum dulcificum seeds were secured from local growers in Africa, and the MFSO was extracted using supercritical CO2 fluid extraction methods in the USA (Pérez, Ruiz del Castillo, Gil, Blanch, & Flores, 2015). The yield of the crude oil extract was 8% (based on dry weight). The HPLC fingerprint of the total methanolic extract of the MFSO. To improve the delivery of the MFSO, such that the MFSO could be released upon contact with the underlying skin progressively over time, the MFSO was incorporated within a flexible styrene‐ethylene/butylene‐styrene copolymer thermoplastic elastomeric gel. To confirm the proper amount of delivery over time, the exudation of the oil from the elastomer gelatinous composition to a surface was determined (Matteliano, Schaffer, & Sutton, 2010). These tests revealed that the gel was capable of releasing and properly delivering the oil for a period of months [unpublished observations]. To form the wristband and achieve targeted delivery of the MFSO, the elastomeric gel was heat bonded to an overlying stretchable fabric with one end attached to a Velcro strap. The wristbands containing MFSO (or vehicle control with no MFSO). The wristbands were the same size, and when worn to comfortably support the wrist without blocking movement, the average pressure generated was 29 mm ± 5 mm hg as per the manufacturer's instructions for comfortable fit. The wristband samples were received at the study site under code in blinded form and stored at ambient humidity and temperature.
Assessment of hand and finger motor skills
A battery of six characteristic and reliable quantitative hand and finger bio‐instrumentation tests used routinely in research studies and clinical practice were utilized to assess the effects of a MFSO wristband on the subject's motor skills performance. Certain modifications from the accepted test methods were performed to assess new parameters or to optimize the measurement of the variables of interest. The tests quantitatively measured 12 hand and finger variables, which included finger tapping speed, endurance until fatigue, explosive power or quickness, and acceleration; accuracy and manual dexterity with fine and gross motor skills, hand steadiness and precision with errors, handwriting speed and mobility, and grip/pinch strength with fatigue. For each participant‐visit‐hand combination, each test was conducted twice in a test–retest for mat (i.e., replicate measurements). Specific clinical procedures were implemented for the performance of the bio‐instrumentation tests in an attempt to reduce procedural and interviewer test bias. On each visit, all subjects' hand and finger motor skill performances were assessed with the same battery of bio‐instrumentation tests. For all tests, the percent difference between right and left hand performance (mean and max values) was calculated and used to determine if the subject met the relevant entrance criterion.
The results were expressed as the number of taps for each individual run including the maximal and mean values among the replicate tests for each hand. It was arbitrarily decided to select and compare a 20‐s time interval near the beginning (at the 10‐ to 30‐s interval) and end of the test (at the 90‐ to 110‐s interval) for the measurements of finger fatigue.
The test was scored by the duration of time (seconds) it took the subject to complete all the segments in the pattern. If the participant raised the pen, moved the paper (more than ½ inch in any direction at any given time), crossed a line within a segment, or if the crossed line spanned additional adjacent segments, it was counted as an error. Subjects were allowed up to 5 errors with the right hand and 20 errors with the left for the test to be counted.
Questionnaires
Participants completed a self‐assessment hand and finger performance outcome questionnaire at every visit. Participants rated the performance of their hands and fingers with regard to movements, strength, and sensation with the use of each hand using a 1 (most positive) to 5 (most negative) rating scale. They were also asked to reveal any perceptual improvements in mobility, skills, strength, and endurance as well as in their performance of 22 commonly routine specific tasks such as typing, texting, and writing.
Statistical analysis
The sample size for this preliminary study was selected to sufficiently characterize the performance of the MFSO treatment group and to provide adequate power to assess the amount of the MFSO group performance that is above and beyond that observed in the gel band control group. Sample sizes of at least 20 subjects in the MFSO group and at least 15 subjects in the control group were deemed to meet these criteria, according to the power analysis. A secondary analysis examined the change from baseline at Visit 4 for the left hand. Questionnaire data were summarized by the treatment group by presenting the number and percentage of subjects included in a given category. No statistical testing was performed on the questionnaire data.
RESULTS
Forty‐six healthy right‐handed subjects were randomized and received treatment. Eight subjects voluntarily withdrew due to personal reasons unrelated to the treatment and did not complete the study, resulting in a total of 38 participants completing the study (MFSO, n = 23; Vehicle, n = 15). Subject ages ranged from 21 to 66 years with a mean (SD) of 42.8 (12.98) years. Most subjects were male (73.7%) and most had a college or postgraduate degree (57.9%). Self‐reported adherence to the study wristband among all subjects was equally high across the two treatment groups (>90% diary‐logged days of use).
Effect of MFSO on hand and finger motor skills
Mean improvements in the hand and finger motor skills parameters were evident with the use of the MFSO band during both treatment intervals. With each hand, in 9 of 12 bio‐instrumentation tests, the MFSO group showed a clinically meaningful average improvement compared with an average worsening in the vehicle group.
The placebo control treatment group did not perform statistically better than the MFSO band treatment group in any of the 12 hand and finger tests. The hand outcomes and wristband use questionnaires analyses indicated that the use of the MFSO wristband was associated with a greater level of favorable responses when compared with the control group. For each of the four categories (i.e., movement, skill, strength, and endurance), at least 39% of the subjects in the MFSO band treatment group reported an improvement using the wristband compared with less than 14% in the control group. In all but one of the 18 improvement categories, the percentage of subjects reporting improvement in the MFSO band treatment group was more than twice that of the control treatment group.
Effect during no treatment on hand and finger motor skills
After 4–6 weeks of no treatment with the right‐hand (Visit 3), there were no clinically meaningful changes for any of the 12 right hand tests.
DISCUSSION
This study is the first clinical trial to demonstrate the safety and efficacy of the use of a fruit seed oil incorporated into a wearable compression garment for improving the performance of hand and finger motor skills. This was also the first placebo‐controlled, double‐blind, clinical study that compared the efficacy of this unique type of combination product with its vehicle. The results of this preliminary clinical study demonstrated a meaningful within MFSO band treatment group improvement in 9 of 12 bioinstrumentation motor skills tests with the use of either hand in right‐handed subjects. In addition, the subjects in the MFSO band treatment group robustly demonstrated statistically significant and clinically meaningful improvement compared with the placebo control group with respect to finger tapping measurements, hand dexterity metrics, and strength assessments. The differences between treatment means were quite substantial that would represent a marked performance benefit when using the MFSO band compared with the control treatment. Furthermore, the self‐assessments also demonstrated that subjects favored the MFSO band over the control band on all tested attributes.
This study design approach provided added benefits because it allowed for a comparison with the contralateral hand serving as an additional no band treatment control and an evaluation of efficacy at two different treatment time intervals. During the use of the MFSO band exclusively on the left hand for 4–6 weeks, the subject's untreated right hand values remained near baseline and showed no clinically meaningful improvements in performance skills. The switch of the MFSO band to its exclusive use on the right hand for 2–4 weeks resulted in an improvement of the right hand performance skills and a concomitant reduction in the performance skills of the left hand. The left hand manifested a major decline returning in the direction toward near‐baseline levels of performance in nearly all of the tests, reversing most of the gains in the improvements previously obtained with the use of the MFSO wristband. These results indicate that for the favorable benefits to continue and persist over time, the MFSO wristband should be routinely worn and not discontinued.
CONCLUSIONS
Right‐handed subjects that used the MFSO band demonstrated clinically meaningful improvements when compared with the vehicle band control group with respect to finger tapping measurements, hand dexterity metrics, and strength assessments. When worn, a wristband containing MFSO can act as an ergogenic aid to improve an individual's hand and finger motor skills and ability to maintain this performance.
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