Deep brain stimulation fine-tuning in Parkinson's disease: Short pulse width effect on speech.

BACKGROUND: subthalamic nucleus deep brain stimulation (STN-DBS) may have a detrimental effect on speech in Parkinson's disease (PD) patients and new stimulation technologies may help in addressing this issue. OBJECTIVE: to evaluate the STN-DBS acute effect of 30 µs pulse width (30PW) versus conventional 60 µs PW (60PW) on speech and identify the core features of voice modified by 30PW. METHODS: seven STN-DBS treated PD patients participated into a pilot cross-sectional study. Motor and speech performances were tested by means of both automatic analysis and blinded clinical evaluations in four stimulation conditions: 30PW and 60PW both at the usual amplitude and at an amplitude just below the threshold for stimulation-related side effects. RESULTS: at the threshold amplitude, 30PW stimulation improved speech intelligibility for both words (p = 0.02) and sentences (p = 0.04), without worsening motor performance. A lower but not statistically significant voice variability and instability and percentage of stuttering disfluencies was also observed. The beneficial effect of 30PW detected by automatic analysis, was confirmed by patients' perception. CONCLUSIONS: STN-DBS treated patients experiencing low speech intelligibility may benefit from a 30PW stimulation trial at a higher amplitude. Deep characterization of PD speech profiles may help in a better application of recent DBS hardware advances.

Is lowering stimulation frequency a feasible option for subthalamic deep brain stimulation in Parkinson's disease patients with dysarthria?

BACKGROUND: The long-term effect of subthalamic nucleus deep brain stimulation (STN-DBS) on dysarthria can be detrimental. A transient beneficial effect of low-frequency stimulation (LFS) has been reported. OBJECTIVE: to investigate if the magnitude of dysarthria could predict the effect of LFS on speech in STN-DBS PD patients and to verify whether the benefit is maintained over time. METHODS: a cohort study, comparing 10 PD patients with severe speech impairment (MDS-UPDRS item 3.1 ≥ 3) with 10 PD patients with mild speech impairment (MDS-UPDRS item 3.1 ≤ 2), all submitted to STN-DBS. Patients were tested in: MED OFF/STIM OFF, MED OFF/STIM ON (130 Hz, high frequency stimulation [HFS]), MED OFF/STIM ON (60 Hz - LFS) and MED ON with both HFS and LFS. The following was assessed in all conditions: voice (fundamental frequency and jitter), speech (articulatory diadochokinesis [DDK], pitch variability, rate and intelligibility) and motor performance (MDS-UPDRS-III). RESULTS: LFS compared to no stimulation and HFS, in the absence of l-dopa effect, significantly improved DDK and speech intelligibility for sentence, among patients with severe speech impairment. During the l-dopa effect, comparing LFS vs. HFS, there was a significant improvement of speech intelligibility in both groups. Five patients with severe speech impairment opted to maintain LFS. After six months, speech benefit was maintained but treatment adjustments were required. CONCLUSIONS: LFS may offer both an immediate and long-lasting improvement of speech in a subgroup of STN-DBS patients with severe speech impairment during HFS. Nevertheless, its effect on motor symptoms may not be preserved over time.

Cross-Cultural Adaptation and Validation of the Italian Version of SWAL-QOL.

The aim of the study was to evaluate the reliability and validity of the Italian SWAL-QOL (I-SWAL-QOL). The study consisted of five phases: item generation, reliability analysis, normative data generation, validity analysis, and responsiveness analysis. The item generation phase followed the five-step, cross-cultural, adaptation process of translation and back-translation. A group of 92 dysphagic patients was enrolled for the internal consistency analysis. Seventy-eight patients completed the I-SWAL-QOL twice, 2 weeks apart, for test-retest reliability analysis. A group of 200 asymptomatic subjects completed the I-SWAL-QOL for normative data generation. I-SWAL-QOL scores obtained by both the group of dysphagic subjects and asymptomatic ones were compared for validity analysis. I-SWAL-QOL scores were correlated with SF-36 scores in 67 patients with dysphagia for concurrent validity analysis. Finally, I-SWAL-QOL scores obtained in a group of 30 dysphagic patients before and after successful rehabilitation treatment were compared for responsiveness analysis. All the enrolled patients managed to complete the I-SWAL-QOL without needing any assistance, within 20 min. Internal consistency was acceptable for all I-SWAL-QOL subscales (α > 0.70). Test-retest reliability was also satisfactory for all subscales (ICC > 0.7). A significant difference between the dysphagic group and the control group was found in all I-SWAL-QOL subscales (p < 0.05). Mild to moderate correlations between I-SWAL-QOL and SF-36 subscales were observed. I-SWAL-QOL scores obtained in the pre-treatment condition were significantly lower than those obtained after swallowing rehabilitation. I-SWAL-QOL is reliable, valid, responsive to changes in QOL, and recommended for clinical practice and outcome research.