Amount of low-frequency band oscillatory suppression

Local field potential recordings of pallidal neuronal activity will be recorded using the Percept neurostimulator. On the one hand, automatically preprocessed peak-biomarker activty in the low-frequency range (7.8-12 Hz) will be recorded continuously using the Chronic BrainSense function of the Percept neurostimulator for one year at a temporal resolution of 1 sample/10 min. Over time and with optimization of clinical DBS settings, low frequency dynamics will change in correlation with symptom improvement. On the other hand, at monthly recordings, local field potentials at a sampling frequency of 250 Hz will be recorded ON and OFF stimulation at various intensities up to the therapeutic stimulation intensity. After preprocessing and transformation to the time-frequency domain, low frequency activity will be compared between different therapy settings.

monthly recordings for 12 months

Proportion of pathological increase in beta band oscillatory activity

Local field potential recordings of pallidal neuronal activity will be recorded using the Percept neurostimulator. On the one hand, automatically preprocessed peak-biomarker activity in the beta band (13-35 Hz) will be recorded continuously using the Chronic BrainSense function of the Percept neurostimulator for one year at a temporal resolution of 1 sample/10 min. Over time and with chronic DBS settings, beta band activity will increase in correlation with development of bradykinesia. On the other hand, at monthly recordings, local field potentials at a sampling frequency of 250 Hz will be recorded ON and OFF stimulation at various intensities up to the therapeutic stimulation intensity. After preprocessing and transformation to the time-frequency domain, beta band activity will be compared between different therapy settings.

monthly recordings for 12 months

Proportion of dystonic symptom improvement in patient reported outcomes

Weekly patient reported outcomes focused on motor symptoms (4 items: general movement, walking, use of hands, neck muscle tenseness) will provide insights into subjective evaluation of participants, on a 9-points likert scale. Lower scores imply improved symptoms.

weekly, through study completion, up to 12 months

Proportion of dystonic symptom improvement in kinematic video-based analysis

Based on weekly video recordings or at least monthly recordings at the lab visits, automated models will be used to assess symptom severity. With DBS optimization, an improvement of symptom severity is expected, that can be objectified in video kinematics as angle of deviation from midline, smaller angles imply reduced deviation and symptom improvement.

weekly, through study completion, for up to 12 months

Proportion of dystonic symptom improvement based on validated scales - Burke Fahn Marsden Dystonia Rating Scale

At the monthly recordings, trained clinicians and movement disorder specialists will assess the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS), lower scores indicate symptom improvement.

monthly, through study completion, for up to 12 months

Proportion of dystonic symptom improvement based on validated scales - Toronto Western Spasmodic Torticollis Rating Scale

At the monthly recordings, trained clinicians and movement disorder specialists will assess Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) in patients with cervical dystonia, lower scores indicate symptom improvement.

monthly, through study completion, for up to 12 months

Proportion of non-motor symptom improvement

Weekly patient reported outcome questionnaires focused on non-motor symptoms, specifically on the symptoms wellbeing, mood, pain, stress, sleep, will provide insights into subjective evaluation of non motor symptoms, rated on a 9-points likert scale. Higher scores imply improved symptoms.

weekly, through study completion, for up to 12 months

Rate of bradykinesia with velocity decrease

At the monthly recordings, finger tapping will be objectively recorded using accelerometry. With chronic DBS, the velocity of the tapping (m/s\^2) will decrease.

weekly, through study completion, for up to 12 months

Rate of bradykinesia with decreased acceleration

At the monthly recordings, finger tapping will be objectively recorded using accelerometry. With chronic DBS, the acceleration (g) in the measured accelerometry data will decrease.

monthly, through study completion, for up to 12 months