Sample size Target (all studies with stimulation on versus stimulation off) Outcome measure Results R
STN (
), cZi (
); pre-op and 12 months post-op Phonatory control: alternations between voicing and voiceless states in a reading task Progressive deterioration of phonatory control but unaffected by DBS [58 ]
STN Perceptual ratings and acoustic analysis Deterioration of overall speech performance (perceptual ratings); mixed results concerning single speech parameters (acoustic analysis) [59 ]
STN (
), cZi (
); pre-op and 12 months post-op Mean intensity during reading, intensity decay during syllable repetition STN: increase of intensity; [60 ]
STN (
), cZi (
) Articulatory capacity, accuracy of plosive consonants STN: increased articulatory rate; [61 ]
STN Acoustic analysis of different speech parameters Mixed results with positive and negative effects on single speech parameters [62 ]
STN Acoustic analysis of syllable repetition precision Deterioration of syllable repetition capacity [63 ]
(I)
with both electrodes within STN,
with only one electrode within STN,
with no electrode within STN Perceptual rating according to UPDRS speech item (I) 50% improvement, 36% deterioration of speech; [64 ]
STN and GPi; pre-op and 6 months post-op Peak velocities of jaw movements STN: deterioration of jaw movement velocity [65 ]
STN; stimulation frequencies with 60 Hz and 130 Hz Perceptual rating, acoustic analysis, and aerodynamic measurements Amelioration of outcome measures under 60 Hz stimulation [66 ]
STN Case reports: description of speech performance Reoccurrence of severe stuttering [67 ]
STN Acoustic analysis of different speech tasks No changes in speech performance [68 ]
STN Articulatory accuracy measured by electropalatography Deterioration in one patient, amelioration in the other patient [69 ]
STN; pre-op, 1 month, 6 months, and 12 months post-op Perceptual analysis based upon validated rating scale Amelioration of speech in
; deterioration in the other patients by an average of
off-medication; deterioration more often with high voltage and medially located electrodes within the left STN [70 ]
STN Aerodynamic measures Increased intraoral pressure in
; increased velopharyngeal closure in
[71 ]
STN Perceptual and acoustic analysis Amelioration of voice, no influence on fluency [72 ]
STN Aerodynamic measures Increased inspiratory driving pressure (
); increased vocal fold closure (
); more benefit from low-frequency stimulation [73 ]
STN; 4 V (high) and 2 V (low) voltage Perceptual analysis based upon validated rating scale Deterioration during high-amplitude stimulation in
, in patients with electrodes in medial and/or posterior position [74 ]
within and above STN; 4 V (high) and 2 V (low) voltage Perceptual analysis based upon validated rating scale Deterioration of speech during high-amplitude stimulation independently from side of stimulation [75 ]
STN Acoustic analysis of sustained vowel phonation Improvement of single measures of voice [76 ]
STN Perceptual ratings by patient, physician, and professional speech therapist, additional acoustic analysis Deterioration of overall speech performance (perceptual ratings); amelioration of single speech/voice parameters (acoustic analysis) [77 ]
STN Perceptual rating and acoustic analysis No deterioration; amelioration of glottal stability and vocal tremor [78 ]
STN Acoustic analysis of articulatory and phonatory function Mixed results with improvement or deterioration of articulation and phonation in different patients [79 ]
STN, different parameter settings Perceptual analysis of different speech tasks Deterioration in
patients under “normal” stimulation parameters; further deterioration during high-amplitude and/or frequency stimulation [80 ]
STN Qualitative description and acoustic analysis Mixed results with improvement and deterioration of speech in the different patients [81 ]
STN Perceptual rating according to UPDRS speech item, PET study Improvement of overall speech performance [82 ]
STN; pre-op and 3 months post-op Perceptual dysarthria assessment and rating according to UPDRS speech item Modest improvement of lip movements, loudness, and pitch; slight reduction of intelligibility [83 ]
STN Acoustic analysis and force measurements of articulatory muscles Decrease of reaction and movement time of articulatory organs; increase of maximal strength and precision; improvement of respiratory and phonatory function [84 ]
STN; follow up at several years post-op Perceptual ratings, measurement of articulatory force (lip and tongue force) Improvement of articulatory force; deterioration of overall speech performance (perceptually rated) in a subgroup of patients [85 ]
STN Case report: descriptive Emergence of dysfluencies under STN-DBS [86 ]
STN Acoustic analysis Improvement of distinctive speech parameters [87 ]
STN; pre-op and 3 months and 6 months post-op Acoustic analysis Mild improvement of sound pressure level and pitch variability [88 ]
STN (
), Vim (
) Measurement of articulatory force (lip and tongue force) Vim: deterioration of static and dynamic control of articulatory organs [89 ]
STN, pre-op and 2 years post-op Descriptive Improvement of oral control and intelligibility [90 ]
STN Perceptual rating according to UPDRS speech item, measurement of articulatory force (lip and tongue force) Improvement of static and dynamic control of articulatory organs; improvement of reaction time; improvement of overall speech performance [91 ]
Vim (patients with tremor) Perceptual rating Development of dysarthria in
[52 ]
