The experimental group will receive a blended physiotherapy program consisting of six physiotherapy treatments over a period of 12 weeks, meaning one treatment session every two weeks. In addition, a smartphone application will offer the patients a daily exercise program, based upon the standard physiotherapy treatment, and psychological counselling. Before the start of the program, the exercises will be tailored to the area, type and degree of the patient's dysfunctions. During the six physiotherapy treatment sessions patients will (if needed), receive additional manual mobilisations to increase mobility of the neck and/or temporomandibular joints or manual techniques to decrease muscle tension in neck and jaw muscles. Additional counselling on knowledge about neck and jaw pain and advice about good posture and movement habits will also be provided by the physiotherapist during these six treatment sessions.

Joint repositioning accuracy (JRA) after flexion, extension and left and right rotation movements will be measured in degrees using the NeckCare Unit. This device, using accelerometer and gyroscope data, is specifically designed for investigating JRA during head-neck relocation tests.

The strength of the deep neck flexor muscles will be assessed according to the standardized protocol proposed by Segarra et al.. The patient lays down in supine position and is asked to lift the head of the table, while holding a double chin. This test is graded by the amount of seconds that the patient can hold this position correctly.

The coordination of the deep neck extensor muscles will be assessed according to the standardized protocol proposed by Segarra et al..he deep neck extensor test will be performed in a four-point-kneeling position. The test will be assessed based on the fulfilment of certain criteria such as presence of dissociation between mid-low cervical and high cervical spine, neutral head position during 20° mid-low cervical extension, absence poked chin, absence excessive tension of Musculus Semispinalis Capitis.

The coordination of the shoulder stabilising muscles will be assessed according to the standardized protocol proposed by Segarra et al.. The scapula stabilisation test will be performed in prone position with one arm elevated. The patient should perform a shoulder depression and lift the elevated arm, without losing the shoulder depression. In case a patient can perform the test correctly, he will be scored as good coordination. All other cases will be scored as bad coordination.

The mobility of the temporomandibular joint will be measured using a ruler. Mouth opening, protrusion and laterotrusion will be objectified.

Active myofascial trigger points will be looked for in the masseter and temporalis muscle and in the sternocleidomastoid, splenius capitis, upper trapezius and levator scapulae muscles. A triggerpoint is considered active when a patient indicated that pressure on the triggerpoint was painful not only locally but also in the radiation area of the respective trigger point.

Pure tone audiometry, to objectify the presence of hearing loss, is performed according to current clinical standards (ISO 8253-1, 1989) using a two-channel Interacoustics AC-40 audiometer in a silent room. Air conduction thresholds are measured by the use of headphones at 125Hz, 250Hz, 500Hz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 6 kHz and 8 kHz. In cases where air conduction thresholds exceed the normality level of 20dB HL at one frequency between 250Hz and 4 kHz, bone conduction thresholds are measured.

Speech reception in quiet (SPIQ) is measured using the Dutch open-set NVA lists developed by the Nederlandse Vereniging voor Audiologie (NVA) or Dutch Society for Audiology. Each list consists of twelve monosyllabic words (consonant-vowel-consonant), of which one is a training item. The speech recognition score is the percentage of correctly identified phonemes. The lists are presented through headphones. The speech reception in noise

The speech reception in noise (SPIN) is assessed by means of the Leuven Intelligibility Sentences Test (LIST) using an adaptive procedure. The frequency spectrum of the noise signal is equal to the long-term average speech spectrum of the sentences. The level of the noise is fixed at 65 dB SPL, while the level of the speech signal is altered depending on the response of the patient. If the participant repeats the keywords of the sentence correctly, the level of the next sentence is decreased by 2 dB SPL. If the participant fails to repeat the keywords, the level is increased

The pitch is the psychoacoustic equivalent of the physical parameter frequency. The tinnitus pitch is obtained by use of a pitch matching technique which is the quantitative and qualitative description of the spectral characteristics of the tinnitus. For this technique, a two-alternative forced-choice procedure was used using the contralateral ear as the reference ear. In cases where tinnitus is perceived bilaterally, the choice of the ear is arbitrary. By this technique, an attempt is made to identify the centre pitch of the tinnitus. When multiple tinnitus sounds are perceived, it is suggested to concentrate on the most troublesome tinnitus sound. Each time a pair of pure tones (or noises in case of noise-like tinnitus), differing by one or more octaves, are presented to the subject, who has to indicate which of the tones resembles the tinnitus the most. This procedure is repeated, and finer adjustments are made to obtain a match of tinnitus pitch as exact as possible.

Loudness is the perceptual correlate of the sound intensity. The tone (or noise) defined as the pitch math is presented to the ipsilateral ear (when appropriate), and a loudness match is made by the use of an alternating forced-choice procedure.

Patients are asked to score the mean and maximum loudness of their tinnitus in the previous week on a 100 mm horizontal line ranging from left: 0 (absence of tinnitus) to right: 100 (as loud as possible, cannot be any louder).

The presence and severity of neck complaints will be evaluated using the NBQ. The NBQ consists of seven questions on the severity of the neck complaints and its interference with the patient's wellbeing and professional and daily activities. The test-retest reliability of the NBQ is moderate (ICC: 0.65). The construct validity is acceptable with both the Neck Disability Index (r: 0.50) and the Copenhagen Neck Functional Index (r: 0.44). The effect size was high (Cohen's d: 1.67), which indicates that the NBQ is highly responsive to changes in cervical spine complaints. The clinically relevant change of the NBQ is a 12 points decrease.

The presence and severity of temporomandibular disorders (TMD) will be evaluated using the TMD pain screener. The TMD pain screener is a 6-item questionnaire regarding pain complaints from the orofacial region, and their dependency on functions, like opening wide or chewing. Internal consistency of the questionnaire is excellent, with a coefficient α value of 0.93, reliability is good (ICC: 0.79), and excellent sensitivity and specificity for diagnosing TMD (0.99 and 0.95-0.98, respectively).

The Hospital Anxiety and Depression Scale (HADS) is used to detect signs of depression and anxiety symptoms. It is a self-assessment scale and was developed to identify the possibility and probability of the presence of anxiety and depression among patients in non-psychiatric clinics. It exists of two subscales, an anxiety subscale (HADS-A) and a depression subscale (HADS-D), both containing seven intermingled items. A high internal consistency was stated for a both the depression and anxiety scale, with respectively a mean coefficient α value of 0.83 and 0.82 . In addition both scales also demonstrated a good sensitivity and specificity of approximately 0.80. The HADS is found to be an instrument of moderate reliability (ICC: 0.56) for screening states of depression and anxiety in the setting of a hospital medical outpatient clinic.

Hyperacusis, a symptom that often co-occurs with tinnitus, is quantified and characterised using the Dutch version of the Hyperacusis Questionnaire (HQ). This questionnaire consists of 14 questions that are answered on a 4-point scale, ranging from 'No' (0 points), 'Yes, a little' (1 point), 'Yes, quite a lot' (2 points) to 'Yes, a lot' (3 points). Scores on the HQ consequently range from 0 to 42, and the cut-off value for hyperacusis is 28 points. Moderate correlations between the HQ, uncomfortable loudness levels, and other health questionnaires and a high Internal consistency of the HQ have been demonstrated.

The EuroQoL EQ-5D questionnaire is the most commonly used method to collect health-related Quality of Life (QoL) data and is recommended by worldwide economic evaluation guidelines such as the NICE recommendations. This questionnaire measures QoL using 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. The response pattern produces a code which represents a health state of the participant. Each health state is associated with a health utility value between 0 and 1 in which 0 represents death and 1 corresponds to perfect health. QoL is necessary to calculate Quality-Adjusted Life Years (QALYs), the most important outcome from the health economics point of view. The 5L-version is preferred over the 3L-version as it is more nuanced and thus more sensitive to gains (or losses) in general health.

The iMTA Productivity Cost Questionnaire (iPCQ) includes three modules measuring productivity losses of paid work due to 1) absenteeism and 2) presenteeism (productivity loss due to paid work) and productivity losses related to 3) unpaid work. The iPCQ delivers the necessary input to calculate productivity loss using the Human Capital Approach in the extended analyses.