The aim of the present study was to explore four individuals' perspective of the way their speech and communication changed as a result of subthalamic nucleus deep brain stimulation treatment for Parkinson's disease. Interviews of two men and two women were analyzed using qualitative content analysis. Three themes emerged as a result of the analysis. The first theme included sub-themes describing both increased and unexpected communication difficulties such as a more vulnerable speech function, re-emerging stuttering and cognitive difficulties affecting communication. The second theme comprised strategies to improve communication, using different speech techniques and communicative support, as well as trying to achieve changes in medical and stimulation parameters. The third theme included descriptions of mixed feelings surrounding the surgery. Participants described the surgery as an unavoidable dramatic change, associated both with improved quality of life but also uncertainty and lack of information, particularly regarding speech and communication changes. Despite negative effects on speech, the individuals were generally very pleased with the surgical outcome. More information before surgery regarding possible side effects on speech, meeting with a previously treated patient and possibly voice and speech therapy before or after surgery are suggested to facilitate the adjustment to the new speech conditions.
Although subthalamic nucleus deep brain stimulation (STN-DBS) treatment for Parkinson’s disease (PD) has been reported to be an effective treatment for advanced motor symptoms of the limbs, such as tremor, rigidity, and bradykinesia, the effects on different speech parameters (phonation, articulation, speech rate) and intelligibility are equivocal [
The speech disorder associated with PD is well described [
When comparing studies to evaluate the effects on speech of STN-DBS in individuals with PD, the one consistent finding appears to be variability. This variability may be accounted for by a number of variables: disease-specific variables, type and degree of dysarthria pre- and/or post-surgery, stimulation-related variables, such as location of electrodes, amplitude, and frequency of stimulation, and speech measures chosen and, so on. Small group studies have so far been unable to capture the relevant variables and describe the individuals who might or might not be suitable candidates for surgery. One of the missing perspectives in this area of research appears to be the individual subjective perspective, a perspective that can be expected to contribute to a deeper understanding of the changes in speech and communication as a result of STN-DBS. Conducting qualitative analysis of semistructured interviews is a suitable methodology to explore individual perspectives and describe the heterogeneity of human experiences [
Data collection was performed through semi-structured interviews, which were subsequently analyzed using qualitative content analysis [
Four individuals were invited to participate in the study. They were selected by the physician in charge of the Motor Disorders Unit at the Neurology Clinic at the local university hospital. The inclusion criteria were Parkinson’s disease, at least 2 years after STN-DBS surgery and health status, cognitive and language skills to be able to participate in an interview situation. It was also considered valuable to include both women and men and individuals who had both shorter and longer experience of the effects of STN-DBS. All four were in contact with the Motor Disorders Unit at the time of the study and were selected by the physician as possible and suitable participants. The head of the Neurology Clinic approved the study as a part of the evaluation of surgical treatment in the clinic.
Basic information describing the participants is included in Table
Demographic data (all names are pseudonyms).
Participant | Gender | Age years | Diagnosis | Disease duration (years) | Years after STN surgery | Total score UPDRS before STN surgery | Total score UPDRS after STN surgery (12 months ) | Speech before | Speech after surgery (6–12 months ) | Speech | Speech |
---|---|---|---|---|---|---|---|---|---|---|---|
Lisa | Female | 71 | Idiopathic Parkinson’s disease | 24 | 4 | Without L- dopa: 37 | Med + stim + 21 | No dysarthria | No dysarthria | Words: | Words: |
Greta | Female | 73 | Idiopathic Parkinson’s disease | 32 | 10 | No data found | Med + stim +10 | Mild* hypokinetic dysarthria | Mild hypokinetic dysarthria | Words: | Words: |
Anders | Male | 61 | Left sided hemiparkinsonism | 10 | 2 | Without L-dopa: 30 | Med + stim + 26 | Mild-moderate mixed dysarthria, speech festinations | Dysarthria | Words: | Reading**** |
Sven | Male | 79 | Idiopathic Parkinson’s disease | 30 | 9 | No data found | No data found | Mild hypokinetic dysarthria | Mild hypokinetic dysarthria | Words: | No data |
*Dysarthria classification: mild = speech affected but intelligibility intact, moderate = intelligibility slightly decreased, severe = speech supported by augmentative and alternative communication [
**Clinical dysarthria test, range 0–4 (normal <0,25; 4 = severe disability) [
***SWINT-Swedish Intelligibility Test, [
Written information regarding the study was sent to the prospective participants, after which they were contacted by telephone. They all agreed to participate and signed a written consent form, including agreeing to the interview being video recorded. They all preferred to be interviewed in their homes. During the interviews, the participants were encouraged to take breaks whenever needed, but no one chose to do so. All the interviews were conducted on a one to one basis, except that the wife of one of the participants was present during the initial part of his interview.
Semistructured qualitative research interviews were conducted and video-recorded by the first author (EA). Prior to actual data collection, two pilot interviews were conducted, with two nonsurgically treated individuals, in order to increase interviewing skills, evaluate the interview guide, and increase trustworthiness.
A semi-structured interview guide was developed gradually, based on knowledge in the area of research and the pilot interviews. Minor adjustments were made during the course of the four interviews. An interview started with open questions regarding disease history which was followed by more specific questions focusing on experiences of speech and communication after STN surgery. Examples of questions from the interview guide were: “Describe if and how your speech has been affected by DBS treatment?”, “When does your communication work well and when does it not?”, and “How are you able to communicate with other people?—known, unknown?”. The sessions lasted between 45 and 60 minutes. Memos were written in connection with the interviews to obtain a first impression of the content. A second, follow-up interview was conducted by phone with participant number 3 (Anders) to collect additional information regarding a specific topic (his reemerging stuttering). No second interviews with the other participants were considered necessary.
The interviews were transcribed verbatim by first author (EA) and the transcriptions were analyzed using qualitative content analysis [
The emergence of the theme “increased and unexpected communication difficulties”.
Quote | Code | Sub-theme | Theme |
---|---|---|---|
Voice less nuanced and stiff, that is sad | Weak and monotonous voice | Increased and unexpected communication difficulties | |
Mind suddenly stops in the middle of communication | Freezing of the mind |
All the participants described changes in different aspects of speech and communication as an effect of STN-DBS, both the surgery and the stimulation. These changes included a weak and monotonous voice and reduced speech intelligibility. However, the overall benefits of the surgery in terms of increased mobility were stressed by all participants. Despite different side effects, they still felt that they “had got their life back” as a result of the surgery. In addition, they were convinced that the progression of their disease symptoms had left them with no choice other than to have the surgery.
The content analysis resulted in 3 themes and 13 subthemes (Table
Overview of findings.
Themes | Subthemes |
---|---|
(1) Increased and unexpected communication difficulties | (1.1) Weak and monotonous voice |
(1.2) Vulnerable speech function affects intelligibility | |
(1.3) Stuttering | |
(1.4) Difficulty reading and writing | |
(1.5) Changed auditory feedback | |
(1.6) Mental fatigue | |
(1.7) Freezing of the mind | |
(2) Strategies to improve communication | (2.1) Speech techniques |
(2.2) Communicative partners’ support | |
(2.3) Changing medical and stimulation parameters | |
(3) Mixed feelings surrounding the surgery | (3.1) An unavoidable, drastic decision |
(3.2) Improved quality of life | |
(3.3) Uncertainty and lack of information |
All four participants reported varying degrees of negative effects on their speech after surgery. One participant did not have any speech or voice problems before the operation but developed difficulties after surgery. Others had dysarthria which worsened after the operation. Some symptoms increased, such as reduced intelligibility and problems with writing.
In addition to a more or less expected deterioration in speech and communication, a number of unexpected difficulties related to communication were described. One participant reported the re-emergence of stuttering after surgery and another described a change in self-perception of her own speech, considered related to auditory feedback. All the participants reported an increase in mental fatigue and difficulty in concentrating for longer periods of time, which had an effect on their social life.
One participant mentioned that her speech improved post surgery, but gradually deteriorated again. The participants described their voices as weak, stiff, and monotonous.
Some participants experienced that other people frequently had difficulty hearing and comprehending their speech; their communication partners had to request clarification over and over again.
One of the participants had stuttered as a child, which was reported to have disappeared at the age of 8–10 years. After surgery, the stuttering re-emerged and had been permanent ever since.
Writing appeared to have been micrographic for all participants before surgery, but the difficulties increased after surgery up to the point where the handwriting was not readable. None of the participants reported difficulty reading before the operation, but one of them reported reading difficulty after surgery. He described the reading impairment as similar to his writing difficulties, as the text merged and lagged behind and was difficult to focus on.
One of the participants felt that the sound of her own voice sometimes changed, but this change was not perceived by people around her. She reported that her voice sounded as though she was talking in a bucket or a can.
The participants reported not having the same social capacity after surgery. After a short time in a large group of people, they became tired.
A couple of participants experienced word retrieval difficulties but also something they described as a “freezing of the mind”. It was not only a question of finding the right words but rather an inability to remember anything because the mind suddenly turned absolutely blank.
As a result of the different speech and communication problems experienced by the participants and described above, they had found ways to improve communication. They reported using different strategies, such as adjusting speech rate and loudness in order to increase speech intelligibility. It was reported that communication partners played an important role in solving communication problems in conversation. Furthermore, the participants said that the level of medication and stimulation parameters were of importance to their speech and communication.
Most participants made conscious use of strategies such as adjusting speech rate. They tried to talk more slowly, as it made them more understandable.
The participants described being difficult to understand in various situations which made participating in social life difficult. For some social functions, the ability to make phone calls is important, something that was considered particularly difficult by some of the participants. This made them dependent on other persons.
The need for several repetitions in order to be understood also led to increased dependence on family and relatives to help out in communicative situations. One participant stressed the importance of having family who knew her very well because when her mind “froze” and she did not remember anything, her husband would fill in or explain the situation to other communication partners.
After the operation, all four participants had been able to reduce their medication considerably, which was perceived as an important improvement. However, adjustments were necessary and varying effects of medication after surgery were reported.
Stimulation settings were also perceived as affecting speech and communication. In particular, one participant had the opportunity to adjust the stimulation parameters himself and made conscious choices to increase his ability to communicate versus moving around.
All four participants described the decision to go ahead with the surgery as a dramatic and unavoidable one, because of increased disease symptoms and less levodopa effect. They all described feelings of uncertainty: they lacked information pre- and postsurgery and also wanted information about possible future changes. In spite of this, they were happy with the decision to have surgery because of the general improvement in quality of life, despite the perceived negative effects on speech and communication.
The participants described their time presurgery as being in a very bad medical state, desperate for a change, willing to try almost anything.
All the participants expressed a feeling of being pleased that the operation was worth it, because of a general increase in quality of life. Although they all experienced adverse effects, they “got their lives back”.
The two women did not express any disappointment at all, although they both experienced a worsening of speech symptoms. The increased mobility and reduced tremor made up for everything.
Some of the participants felt that they needed more information, both before and after surgery, about what to expect in terms of possible side effects, and also how the disease could be expected to develop as a result of surgery. They expressed disappointment at the amount of information that was offered and one participant suggested meeting with other patients who were treated with STN-DBS.
The participants had different thoughts about the future. The disease symptoms changed constantly and the participants needed to deal with these changes continually. Feelings of uncertainty were described by all participants. They wanted to know how both the disease and the speech impairment would develop.
To summarize, this study investigated how speech and communication were perceived by four individuals with Parkinson’s disease, following surgical treatment with deep brain stimulation to the subthalamic nucleus. The participants described different improvements such as increased mobility and a radical reduction in tremor and medication. At the time of surgery, they all felt that they were in such a bad medical state that they had no other choice but to agree to the surgery. Furthermore, they said that speech and communication deteriorated as a result of surgery and/or stimulation.
The findings of the present study add an in-depth individual perspective to what is known about the speech effects of subthalamic stimulation. The reports from the participants described reduced speech intelligibility, which agrees very well with recent group studies (e.g., [
One of the participants reported the re-emergence of developmental stuttering, not as a symptom of the disease
The description of mental fatigue, freezing of the mind, and vulnerable speech function is an illustration of the way cognitive factors and cognitive decline can be influential. This makes the contribution and support of significant others important. Communication partner support is important for individuals with dysarthria caused by Parkinson’s disease in general [
This study confirms numerous studies describing the dramatic positive effects of STN-DBS on mobility and tremor. None of the four participants regretted going through with the surgery, despite the fact that they experienced side effects. Bearing in mind the very small number of subjects, a possible gender difference in the perceptions of surgery outcome might exist. Apart from the fact that the proportion of male patients who undergo STN-DBS exceeds the reported male/female ratio of PD patients [
One of the factors that could increase patient satisfaction is clearly increased information relating to the procedure. The participants in the present study described a need for more information, regarding both the surgery and the possible side effects. This is consistent with the study by Montel and Bungener [
Trustworthiness aspects are discussed in terms of credibility, confirmability, dependability, and transferability [
There are divergent meanings of using participant validation, therefore this was not done. A participant may have changed his/her views due to temporal aspects and other potential changes in his/her situation [
It was stated in the introduction that the one consistent finding in studies of STN-DBS in PD is variability and the participants in the present study add to this variance. Because of the individual variability, as Montel and Bungener [