Evaluation of Intensive Language Therapy

Effectiveness of High-frequency Specific Speech Therapy on Verbal Fluency Decline and/ or Verbal Apraxia in Patients With Parkinson's Disease With and Without Deep Brain Stimulation (DBS) - a Randomized Controlled Single-blinded Trial

Due to Parkinson's Disease (PD) speech and language (SL) deficits may occur. Further, the literature reports that PD patients, who have not undergone deep brain stimulation (DBS), have deficits regarding voice quality (e.g. loudness and intelligibility of their voice), while PD patients who have undergone DBS suffer from deficits in word retrieval and speech apraxia symptoms. To-date, therapeutic approaches focusing specifically on SL deficits observed in PD-DBS patients are yet to be developed and evaluated.

Therefore, this study investigates the short-and longterm effectiveness of specific and intensive, high-frequency speech-language therapy in terms of reducing SL-deficits compared to a nonspecific and non-verbal sham treatment (i.e. a rhythmic balance-movement training (rBMT)) as well as to a 'no-therapy' condition.

In the course of Parkinson's disease (PD) speech and language (SL) deficits may often emerge. In addition, severe verbal fluency (VF) decline has been repeatedly observed in the context of deep brain stimulation (DBS) in PD. Interestingly, while PD non-DBS patients have deficits with respect to loudness and intelligibility of their voice, PD patients who have undergone DBS (PD-DBS) suffer rather from difficulties in semantic and phonemic word retrieval, and from speech apraxia symptoms.

However, to-date and to the best of our knowledge, therapeutic approaches focusing specifically on SL deficits observed in PD-DBS patients are yet to be developed and evaluated regarding their effectiveness. Thus, this study investigates the short-and longterm effectiveness of specific and intensive, high-frequency speech-language therapy in terms of reducing SL-deficits compared to a nonspecific and non-verbal sham treatment (i.e. a rhythmic balance-movement training (rBMT)) as well as to a 'no-therapy' condition.

Inclusion Criteria for all groups:

• The patient is able to cooperate
• The patient has the mental competence to provide informed consent to participate in the study
• The patient speaks and understands German

Specific Inclusion Criteria for the DBS Group

• Fulfilling the above stated inclusion criteria as stated in a, b and c above
• The patient is responsive to Levodopa (L-DOPA)
• Having received or being scheduled for DBS

Exclusion Criteria:

• Severe psychiatric disease difficult to treat (compulsive disorder, depression, mania, psychosis, anxiety as outlined in International Classification of Diseases (ICD-10) (WHO 2015, current version).
• Patient with dementia (DMS-V, Mini-Mental-Status-Test (MMS) <24, Montreal Cognitive Assessment (MoCa) <21)
• Secondary Parkinsonism
• Age ≤18 years
• Pregnancy (early onset)
• Presence of a known disease other than PD that shortens the life expectancy
• Mental incompetence to provide informed consent to participate in the study
• Previous intracranial surgery
• Epilepsy
• Contraindications for DBS seen in MRI-scan (malignant tumour, severe microvascular disease)
• Insufficient skills of German language for participating in neuropsychological evaluations
• Sensory problems, severe enough to significantly interfere with neuropsychological assessment
• Alcohol and/or drug addiction