Centre of pressure golf swing movement strategies are better defined using a continuous approach than by segregated styles.

The relationships between movement style and golf performance have been well researched, but the premise of segregated movement styles has not been fully examined. The purpose of this investigation was to examine the postulation that centre of pressure data are not best described by segregated styles but instead by a continuum and to determine relationships between centre of pressure, handicap and clubhead speed using a continuous approach. Centre of pressure paths of driver and 5-iron shots from 104 amateur golfers were analysed using discrete and continuous methods. Discrete methods used different cluster evaluation criteria which result in two-cluster and twenty-cluster solutions being considered "optimum". The two-cluster solution showed the characteristics of "front-foot" and "reverse" centre of pressure styles. However, a continuous principal component analysis method revealed that the clusters were not well separated and provided support for a multidimensional continuum. The principal components had a high correlation with handicap and clubhead speed. Lower handicap and higher swing speed golfers tended to display a centre of pressure with a "front-foot" style and a fast transition towards the front foot at the start of the downswing. A continuous characterisation of centre of pressure styles has more utility than the segregated styles previously described.

The relationship between skill and ground reaction force variability in amateur golfers.

It is accepted that highly skilled golfers are more consistent in their clubhead presentation and shot outcomes than their lesser skilled counterparts. However, the relationships between movement variability, outcome variability and skill in golf are not particularly well understood. This study examined the ground reaction force variability of one-hundred and four amateur golfers for shots with drivers and 5-irons. Principal component analysis was used as a data reduction technique and allowed all three components of ground reaction force to be considered together. There were statistically significant trends for the higher skilled golfers to display lower variability in two of the five principal components (driver) and four of the five principal components (5-iron). A similar trend was also observed in the other principal components, but these trends were not statistically significant. Intra-individual variability was much lower than inter-individual variability across all golfers; the golfers were each relatively consistent in maintaining their own ground reaction force patterns. Lower variability in ground reaction forces may partly explain how highly skilled golfers maintain lower variability in shot outcomes.

Quantifying tinnitus suppression in cochlear implantation using tinnitus interval-limited tracking.

OBJECTIVES: Quantify the effects of cochlear implants (CI) on tinnitus suppression in patients with previous cochlear implantation using a novel audiologic sequence: Tinnitus Interval Limited Tracking (TILT). STUDY DESIGN: Prospective cohort study. METHODS: Consecutive patients with tinnitus and previous cochlear implantation for profound hearing loss underwent an audiologic testing sequence called TILT. Patients rated tinnitus severity using the validated Tinnitus Handicap Inventory (THI) as well as a visual analog scale at baseline and in a variety of audiologic scenarios. Changes in tinnitus severity between scenarios allow for the isolation of the effects of masking and electrical stimulation on the reduction of tinnitus. RESULTS: Twenty patients were enrolled, 10 of whom have tinnitus with average THI 30.2 (standard deviation 22.6). Patients had an acute decrease in tinnitus severity when their CIs were turned on, even in the absence of noise in a soundproof booth. This effect reversed once the CIs were turned off. This effect was greater in magnitude than with masking that occurred with the presentation of soft speech. Acute tinnitus severity trended toward improvement with increased level of presented speech. Degree of improvement was not correlated with THI. CONCLUSION: Acute tinnitus suppression in patients using CIs is multifactorial. Masking plays a role; however, it cannot sufficiently account for the totality of symptom improvement experienced by CI patients. Quantifiable tinnitus suppression observed when a CI is turned on, even in the absence of audiologic stimulation, suggests that electrical stimulation is involved in the mechanism of symptom improvement in these patients. LEVEL OF EVIDENCE: 4 Laryngoscope, 130: 2047-2052, 2020.

'Compassionate use' protocol for auditory brainstem implantation in neurofibromatosis type 2: Early House Ear Institute experience.

OBJECTIVE: To report the preliminary outcomes of auditory brainstem implantation (ABI) under a compassionate use protocol for two ABI devices that are not approved by the US Food and Drug Administration. METHODS: A retrospective review was performed of neurofibromatosis type 2 (NF2) patients who underwent microsurgery for vestibular schwannoma (VS) and placement of either the Cochlear ABI541 or Med-El Synchrony ABIs. Peri-operative and device- related complications were reviewed. Audiometric performance was also evaluated. RESULTS: Seven patients received either the Cochlear ABI541 (6) or the Med-El Synchrony ABI (1) after the resection of VS. No device or patient-related complications occurred to date. Surgical times and early audiological performance are similar to our previous experience with the Cochlear ABI24 device. CONCLUSIONS: Early experience with the Cochlear ABI541 and Med-El Synchrony ABI devices under a compassionate use protocol suggest that both devices are safe with comparable utility to the Cochlear ABI24 device.

Tinnitus Suppression After Auditory Brainstem Implantation in Patients With Neurofibromatosis Type-2.

OBJECTIVE: To evaluate whether an auditory brainstem implant (ABI) can impact levels of tinnitus in neurofibromatosis type-2 (NF2) patients who have undergone translabyrinthine craniotomy for vestibular schwannoma (VS) removal and to evaluate the burden of tinnitus in these patients. STUDY DESIGN: A retrospective case series and patient survey. SETTING: Tertiary neurotologic referral center. PATIENTS: NF2 patients who underwent translabyrinthine removal of VS and ABI placement between 1994 and 2015. INTERVENTIONS: A survey, retrospective review and two validated tinnitus handicap questionnaires (tinnitus handicap inventory [THI] and tinnitus visual analogue scale [VAS]) were used to characterize the degree of tinnitus in NF2 patients and whether an ABI can alter tinnitus levels. MAIN OUTCOME MEASURES(S): Survey results, THI and VAS scores. RESULTS: One hundred twelve ABI users were contacted and 43 patients (38.3)% responded to our survey. Tinnitus was reported in 83.7% of patients. The THI score for responders was 17.8 ±â€Š20.5 standard deviation (SD). For survey participants, the ABI reduced tinnitus levels (mean VAS: Off = 3.5; On 1-h = 2.1; p = 0.048). For patients who subjectively reported that the ABI reduced tinnitus loudness, tinnitus levels were immediately reduced on ABI activation and after 1 hour of use (mean VAS: Off = 4.8; On = 2.4; On 1-h = 1.8; p < 0.01). Suppression did not continue after the device was turned off. Audiological performance with the ABI did not correlate with tinnitus suppression. CONCLUSION: NF2 patients who have undergone removal of VS have a significant tinnitus handicap and benefit from tinnitus suppression through utilization of an ABI possibly through masking or electrical stimulation of the auditory brainstem.

Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics.

The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives. Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness. Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45% (p < 0.001) and 0.7% (p = 0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact (p < 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact (p = 0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing (p < 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft (p = 0.003). Overall, and taking effect sizes into account, the changes in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.

Variability in clubhead presentation characteristics and ball impact location for golfers' drives.

The purpose of the present study was to analyse the variability in clubhead presentation to the ball and the resulting ball impact location on the club face for a range of golfers of different ability. A total of 285 male and female participants hit multiple shots using one of four proprietary drivers. Self-reported handicap was used to quantify a participant's golfing ability. A bespoke motion capture system and user-written algorithms was used to track the clubhead just before and at impact, measuring clubhead speed, clubhead orientation, and impact location. A Doppler radar was used to measure golf ball speed. Generally, golfers of higher skill (lower handicap) generated increased clubhead speed and increased efficiency (ratio of ball speed to clubhead speed). Non-parametric statistical tests showed that low-handicap golfers exhibit significantly lower variability from shot to shot in clubhead speed, efficiency, impact location, attack angle, club path, and face angle compared with high-handicap golfers.

Determination of the swing technique characteristics and performance outcome relationship in golf driving for low handicap female golfers.

Previous studies on the kinematics of the golf swing have mainly focused on group analysis of male golfers of a wide ability range. In the present study, we investigated gross body kinematics using a novel method of analysis for golf research for a group of low handicap female golfers to provide an understanding of their swing mechanics in relation to performance. Data were collected for the drive swings of 16 golfers using a 12-camera three-dimensional motion capture system and a stereoscopic launch monitor. Analysis of covariance identified three covariates (increased pelvis-thorax differential at the top of the backswing, increased pelvis translation during the backswing, and a decrease in absolute backswing time) as determinants of the variance in clubhead speed (adjusted r (2) = 0.965, P < 0.05). A significant correlation was found between left-hand grip strength and clubhead speed (r = 0.54, P < 0.05) and between handicap and clubhead speed (r = -0.612, P < 0.05). Flexibility measures showed some correlation with clubhead speed; both sitting flexibility tests gave positive correlations (clockwise: r = 0.522, P < 0.05; counterclockwise: r = 0.711, P < 0.01). The results suggest that there is no common driver swing technique for optimal performance in low handicap female golfers, and therefore consideration should be given to individual swing characteristics in future studies.

Influence of shaft length on golf driving performance.

The aim of this study was to determine how shaft length affects golf driving performance. A range of drivers with lengths between 1.168 m and 1.270 m, representing lengths close to the 1.219 m limit imposed by R&A Rules Limited (2008), were assembled and evaluated. Clubhead and ball launch conditions and drive distance and accuracy were determined for seven category 1 golfers (handicaps 0.21 +/- 2.41) who performed shots on a purpose-built practice hole. As shaft length increased from 1.168 m to 1.270 m, initial ball velocity increased (+ 1.8 m/s, P < 0.01). Ball carry (+ 4.3 m, P = 0.152) also increased, although not significantly so. Furthermore, as shaft length increased, for all club comparisons there was no decrease in accuracy. Ball launch conditions of spin components and launch angle remained unaffected by shaft length. Launch angle increased (0.8 degree, F = 1.074, P = 0.362) as driver shaft length increased. Our results show that clubhead and ball velocity together with ball carry tended to increase with no loss of accuracy.