Word-level intelligibility after caudal zona incerta stimulation for Parkinson's disease

Newly designed flat surface artificial tongue system for speech improvement in glossectomy patients: A preliminary study

PURPOSE

To design an efficient tongue prosthesis with reproducibility and to objectively evaluate improvement in speech function.

METHODS

A silicon anatomical artificial tongue (AT) and a flat surface artificial tongue system (FTS) were used in our study. Twenty healthy participants (10 males and 10 females, 26.3 ± 1.8 years) were fitted with a tongue movement suppression appliance (TSA) that fit the dental arch to simulate the glossectomy condition. TSA, TSA + FTS, and TSA + AT simulated the state of glossectomy patients without artificial tongue, with normal artificial tongue, and newly designed artificial tongue, respectively. Three speech intelligibility tests were performed for each of the following conditions: pronouncing 100 Japanese monosyllables, 40 Japanese words, and reading a short story. One-way ANOVA, Wilcoxon signed-rank test, and Tukey-Kramer post-hoc test were used for statistical analyses.

RESULTS

Significant differences were observed for 100 Japanese monosylla bles and 40 Japanese words between the TSA + FTS, TSA, and TSA + AT conditions (p ‹ 0.05). Regarding the speech intelligibility test for reading a short story, the TSA + FTS condition resulted in a significantly higher speech intelligibility than the TSA and TSA + AT conditions (p ‹ 0.05).

CONCLUSIONS

A flat surface artificial tongue system contributed to the improvement in speech function. This structure can be easily used in cases where conventional artificial tongue are applicable, regardless of variation in the oral condition; thus, making it a widely applicable treatment option for glossectomy patients.

Deep Brain Stimulation in Parkinson's Disease: New and Emerging Targets for Refractory Motor and Nonmotor Symptoms

Parkinson's disease (PD) is a progressive neurodegenerative condition characterized by bradykinesia, tremor, rigidity, and postural instability (PI), in addition to numerous nonmotor manifestations. Many pharmacological therapies now exist to successfully treat PD motor symptoms; however, as the disease progresses, it often becomes challenging to treat with medications alone. Deep brain stimulation (DBS) has become a crucial player in PD treatment, particularly for patients who have disabling motor complications from medical treatment. Well-established DBS targets include the subthalamic nucleus (STN), the globus pallidus pars interna (GPi), and to a lesser degree the ventral intermediate nucleus (VIM) of the thalamus. Studies of alternative DBS targets for PD are ongoing, the majority of which have shown some clinical benefit; however, more carefully designed and controlled studies are needed. In the present review, we discuss the role of these new and emerging DBS targets in treating refractory axial motor symptoms and other motor and nonmotor symptoms (NMS).

Swallowing safety in Parkinson's disease after zona incerta deep brain stimulation

OBJECTIVES

The objective of this study was to examine swallowing function in patients with Parkinson's disease before and after caudal zona incerta deep brain (cZI DBS) surgery. The aims were to examine the effect of cZI DBS on swallowing safety regarding liquid and solid food, as well as to identify the effect of cZI DBS on body mass index (BMI) and specific items from part II of the Unified Parkinson's Disease Rating Scale (UPDRS).

MATERIALS AND METHODS

The median age of the 14 patients was 57 years (range 46-71), with a median disease duration of 6 years (range 2-13). The present sample is an extension of a previous report, into which six additional patients have been added. Fiber endoscopic examinations of swallowing function, measures of BMI, and evaluation of UPDRS part II items were made before and 12 months after surgery, with and without activated DBS.

RESULTS

There were no significant changes due to cZI DBS regarding penetration/aspiration, pharyngeal residue or premature spillage (p > .05). Median BMI increased by +1.1 kg/m² 12 months after surgery (p = .01, r = .50). All reported specific symptoms from the UPDRS part II were slight or mild. A significant improvement regarding handling of utensils was seen 12 months postoperatively (p = .03, r = -.42).

CONCLUSIONS

Caudal zona incerta DBS was found not to have a negative impact on swallowing safety. A significant increase in postoperative weight was observed, and speech seemed to be slightly negatively affected, whereas handling of utensils was improved with cZI DBS.

Swallowing Quality of Life After Zona Incerta Deep Brain Stimulation

OBJECTIVES

The management of Parkinson's disease (PD) has been improved, but management of signs like swallowing problems is still challenging. Deep brain stimulation (DBS) alleviates the cardinal motor symptoms and improves quality of life, but its effect on swallowing is not fully explored. The purpose of this study was to examine self-reported swallowing-specific quality of life before and after caudal zona incerta DBS (cZI DBS) in comparison with a control group.

METHODS

Nine PD patients (2 women and 7 men) completed the self-report Swallowing Quality of Life questionnaire (SWAL-QOL) before and 12 months after cZI DBS surgery. The postoperative data were compared to 9 controls. Median ages were 53 years (range, 40-70 years) for patients and 54 years (range, 42-72 years) for controls.

RESULTS

No significant differences were found between the pre- or postoperative scores. The SWAL-QOL total scores did not differ significantly between PD patients and controls. The PD patients reported significantly lower scores in the burden subscale and the symptom scale.

CONCLUSIONS

Patients with PD selected for cZI DBS showed good self-reported swallowing-specific quality of life, in many aspects equal to controls. The cZI DBS did not negatively affect swallowing-specific quality of life in this study.

Lead Angle Matters: Side Effects of Deep Brain Stimulation Improved With Adjustment of Lead Angle

BACKGROUND

Targeting the subthalamic nucleus (STN) for deep brain stimulation (DBS) using standard stereotactic coordinates in conjunction with high-resolution magnetic resonance imaging (MRI) generally results in effective symptomatic relief for the cardinal motor features of Parkinson's disease (PD). The angle of approach, however, influences the resultant field of stimulation and can lead to undesired side effects.

METHODS

We review a case where symptomatic improvement was accompanied by significant side effects despite reasonable STN stereotactic base coordinates. Revision of the lead using similar base coordinates but a significantly different angle of approach greatly improved the outcome.

RESULTS

Stimulation ventromedial to the STN improved tremors but brought about dysarthria and dystonia. Computer-based stimulation field modeling helped understand the regions associated with the side effects and illustrate the difference between pre- and post-revision stimulation fields.

CONCLUSION

Lead angle can impact DBS outcome and should be taken into consideration.

Speech intelligibility in Parkinson's disease patients with zona incerta deep brain stimulation

OBJECTIVES

To investigate the effects of l-dopa (Levodopa) and cZi-DBS (deep brain stimulation in caudal zona incerta) on spontaneous speech intelligibility in patients with PD (Parkinson's disease).

MATERIALS AND METHODS

Spontaneous utterances were extracted from anechoic recordings from 11 patients with PD preoperatively (off and on l-dopa medication) and 6 and 12 months post bilateral cZi-DBS operation (off and on stimulation, with simultaneous l-dopa medication). Background noise with an amplitude corresponding to a clinical setting was added to the recordings. Intelligibility was assessed through a transcription task performed by 41 listeners in a randomized and blinded procedure.

RESULTS

A group-level worsening in spontaneous speech intelligibility was observed on cZi stimulation compared to off 6 months postoperatively (8 adverse, 1 positive, 2 no change). Twelve months postoperatively, adverse effects of cZi-DBS were not frequently observed (2 positive, 3 adverse, 6 no change). l-dopa administered preoperatively as part of the evaluation for DBS operation provided the overall best treatment outcome (1 adverse, 4 positive, 6 no change).

CONCLUSIONS

cZi-DBS was shown to have smaller negative effects when evaluated from spontaneous speech compared to speech effects reported previously. The previously reported reduction in word-level intelligibility 12 months postoperatively was not transferred to spontaneous speech for most patients. Reduced intelligibility due to cZi stimulation was much more prominent 6 months postoperatively than at 12 months.

Perceived articulatory precision in patients with Parkinson's disease after deep brain stimulation of subthalamic nucleus and caudal zona incerta

The effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and caudal zona incerta (cZi) on speech articulation in patients with Parkinson's disease (PD) was investigated. Read speech samples were collected from nine patients with STN-DBS and 10 with cZi-DBS. The recordings were made pre-operatively and 12 months post-operatively with stimulator on and off (on medication). Blinded, randomised, repeated perceptual assessments were performed on words and isolated fricatives extracted from the recordings to assess (1) overall articulatory quality ratings, (2) frequency of occurrence of misarticulation patterns and (3) fricative production. Statistically significant worsening of articulatory measures on- compared with off-stimulation occurred in the cZi-DBS group, with deteriorated articulatory precision ratings, increased presence of misarticulations (predominately altered realisations of plosives and fricatives) and a reduced accuracy in fricative production. A similar, but not significant, trend was found for the STN-DBS group.