Key points

Introduction

It has been widely recognized that the clinical phenotypes of patients with Tourette syndrome (TS) extend beyond motor and vocal tics in the vast majority of patients. ^, The proportion of cases who present with behavioral comorbidities in association with tics is around 90%, with lower figures in patients with persistent motor or vocal tic disorders—which can be seen as “truncated forms” of TS. ^, The physical and psychological consequences of an often painful and stigmatizing condition that first presents in childhood can be far-reaching.

There is no universally agreed-upon definition of the construct of health-related quality of life (QoL), and the connection between clinical symptoms and QoL is complex. A widely used operational definition suggests that subjective QoL can be seen as the gap between patients’ expectations and their actual experiences. This concept offers a practical framework for use in routine clinical practice, explaining the increasing use of QoL as a primary measure for health monitoring and interventions across various medical conditions.

QoL outcome measures play a crucial role in assessing the impact of neurologic and neuropsychiatric conditions on the individuals’ overall well-being. ^, These measures provide valuable insights into the physical, psychological, social, and cognitive aspects of patients’ lives, beyond mere motor and/or sensory symptomatology. By quantifying subjective experiences and functional abilities, QoL measures aid in treatment planning, monitoring disease progression, and evaluating the effectiveness of neuropsychiatric interventions. Moreover, QoL-informed approaches facilitate patient-centered care by considering the individual’s perspective and priorities. Finally, QoL assessments contribute to research by enhancing understanding of the holistic impact of conditions, informing health care policies, and guiding resource allocation for optimal patient outcomes.

Clinical research on QoL in patient with TS and other neurodevelopmental tic disorders began over 2 decades ago, and our knowledge about the impact of these conditions on patients’ lives has steadily increased over time. Although we are still far from having a comprehensive picture of all the nuances of the phenotypical correlates of QoL, both treatment implementation and outcome monitoring can already be informed by preliminary findings derived from this relatively new and promising research field.

Measuring quality of life in patients with Tourette syndrome

Clinical assessments and clinician-rated measures typically rely on clinical judgment and observation to offer an external perspective on the impact of a health condition on the patient’s life. Because this approach draws on the clinician’s expertise and professional insights, it may be influenced by the clinician’s biases or interpretation of the patient’s condition. On the other hand, self-rated measures involve individuals directly reporting their own perceptions of their QoL through standardized instruments (questionnaires or surveys). These assessments provide a subjective perspective, allowing individuals to express their personal experiences and priorities. Self-rated measures are valuable for capturing the unique aspects of an individual’s QoL that may not be apparent to clinicians. However, they are not problem-free, as patients’ responses may be influenced by factors such as cognitive processes, social desirability, and assessment conditions.

Both clinician-rated and self-rated measures of QoL have their strengths and limitations, and their combined use can offer a comprehensive understanding of an individual’s well-being in clinical practice and research settings. Moreover, self-rated measures are often combined with proxy-rated measures, especially in younger patients. Proxy-rated measures of QoL typically involve a family member, teacher, or caregiver, providing an assessment of the individual’s well-being. It is important to note that consistent findings across different clinical populations have revealed moderate correlations between parent and child ratings on functional impairment or QoL. ^, Such discrepancies are particularly relevant to TS populations: child-reported QoL has been shown to more strongly correlate with tic severity than parent-reported pediatric QoL, as some parents may poorly distinguish impairment related to tics from impairment related to comorbidities. These findings may be also related to parents placing more emphasis on comorbid conditions, especially disruptive behaviors such as attention-deficit and hyperactivity disorder (ADHD), while children more readily notice the impact of tics.

Generic measures of QoL assess overall well-being across various domains applicable to any population, irrespective of health conditions. These instruments allow for comparisons across different populations but may lack sensitivity to specific health conditions. Disease-specific measures of QoL target particular health conditions, providing more focused assessments of how the disease impacts various aspects of life. Thus, these measures offer greater sensitivity to condition-specific challenges, and their use has become increasingly more widespread over time.

The Gilles de la Tourette Syndrome-Quality of Life Scale (GTS-QOL) is the first disease-specific instrument developed with the aim of understanding the impact of TS on individuals’ well-being across various domains of life and cultural contexts ( Table 1 ).

Developed in 2008, the GTS-QOL assesses the perceived impact of TS symptoms on various aspects of daily functioning, such as relationships, work, and leisure activities. Individuals rate each of the 27 items covering different aspects of life affected by TS on a Likert scale, providing valuable insights into their subjective experience of living with TS. The GTS-QOL has become a valuable tool for clinicians and researchers alike to assess the subjective experience of living with TS and the effectiveness of interventions aimed at improving QoL. Five years later, the Gilles de la Tourette Syndrome-Quality of Life Scale for children and adolescents (C&A-GTS-QOL) became available, first in its Italian version. As in the GTS-QOL, 27 items are complemented by a visual analogue scale (VAS) and are grouped into 4 QoL domains (physical, psychological, obsessional, and cognitive). Both the items and the VAS are self-rated in the adolescent version (12–18 years) or parent-rated in the child version (6–11 years).

One of the strengths of the GTS-QOL is its adaptability across different cultural and linguistic backgrounds. As TS is a neurodevelopmental disorder with a global prevalence, it is essential to ensure that assessment tools like the GTS-QOL are culturally and linguistically appropriate for diverse populations. Translation and adaptation of the scale into different languages play a crucial role in achieving this goal. The English version of the C&A-GTS-QOL was published in 2017. Psychometric testing of the scale yielded a slightly different structure, with the identification of 6 QoL domains (physical, psychological, obsessive-compulsive, cognitive, coprophenomena, activities of daily living [ADL]). More recently, the GTS-QOL was adapted and validated in French, with minor differences in the 6 QoL domains (physical/ADL, psychological, obsessive-compulsive, cognitive, echo-coprophenomena, and social). In the French version of the C&A-GTS-QOL, the underlying structure of the instrument includes 5 QoL domains (physical, psychological, echo-coprophenomena/obsessive-compulsive, cognitive, and social). Finally, the Japanese version of the GTS-QOL, published in 2022, retains the original 4 QoL domains (physical, psychological, obsessional, and cognitive).

In young people with TS and other tic disorders, a strong overlap has been consistently found between the areas covered by the C&A-GTS-QOL and those covered by the Child Tourette’s Syndrome Impairment scale (CTIM). The CTIM was originally developed in 2007 as a 74-item measure of functional impairment in youth with TS. This scale rates problems in school (11 items), social (11 items), and home (15 items) domains separately for tics and for non-tic symptoms (comorbid diagnoses). The items of the CTIM can be rated either by parents (CTIM-P) or by children themselves (CTIM-C). The Mini-Child Tourette Syndrome Impairment Scale (mini-CTIM) is a 12-item abbreviated version of the CTIM, also incorporating both parent-rated (mini-CTIM-P) and child-rated (mini-CTIM-C) impairments.

Studies of the clinical correlates of quality of life in patients with Tourette syndrome

Both generic and disease-specific instruments measuring QoL have been incorporated into research protocols assessing the subjective well-being of patients with TS and other tic disorders. Since the development and validation of the first disease-specific instrument, 16 studies focusing on the assessment of QoL in patients with TS have used disease-specific instruments: the GTS-QOL was used in 6 studies, the CTIM-P was used in 4 studies ^{, , ,} ; the C&A-GTS-QOL was used in 3 studies, the mini-CTIM-C and the mini-CTIM-P were used in 2 studies each, ^, and the CTIM-C and the TSIS were used in 1 study each ( Table 2 ).

The studies were conducted between 2012 and 2023 across 3 continents: 7 studies were conducted in the United States, 3 each in Italy and the United Kingdom, and 1 each in Australia, Germany, and Spain. All the studies took place in specialist clinics for patients with tic disorders, with the exception of 3 studies: 1 online survey conducted in the United States, 1 online survey conducted in Germany, and 1 postal survey conducted in Australia. These 16 studies recruited a combined number of 1651 patients, with sample sizes ranging from 22 to 524 patients. The mean ages of the patients were between 10 and 33 years, with the majority of them being males across all studies (proportions of males ranging from 52% to 89%). The studies largely adopted a cross-sectional protocol, with the exception of one study, which was characterized by a longitudinal design. The proportions of patients with comorbid obsessive-compulsive disorder (OCD) and ADHD were similar, as they ranged from 7% to 54% for OCD and from 14% to 60% for ADHD. By using a disease-specific instrument, it was possible to dissect the multidimensional impact of both tics and comorbid conditions of different aspects of QoL across the lifespan: childhood, adolescence, the delicate transition phase between adolescence and adulthood, and later life. In addition, complex tics (coprophenomena) and tic-related factors, such as sensory phenomena and interoceptive accuracy, were singled out as individual contributors to QoL. The studies using the CTIM contributed valuable information about children’s versus parents’ impairment ratings, as well as QoL perception in male versus female adolescents.

Generic instruments can usefully complement findings from disease-specific QoL measures. To date, a total of 30 studies have addressed the QoL construct using generic rating scales in patients with TS and other tic disorders across all ages ( Table 3 ).

Table 3

Summary of studies on health-related quality of life in patients with Tourette syndrome and other chronic tic disorders: studies using generic instruments

Study	Country	Setting	N	Mean Age (years); Range	Male Gender (%)	Comorbid OCD (%)	Comorbid ADHD (%)	QoL measure(s)	Main Findings
Elstner et al, 2001	United Kingdom	Specialist clinic	103 (+145 epilepsy controls) (+930 SF-36 normative data)	29; 16–54	68%	21%	NA	QOLAS; SF-36	QoL in patients with TS (and those with epilepsy) worse than in healthy controls; QoL domains most affected: physical, psychological, social, occupational, cognitive; reported difficulty in making/maintaining relationships; effects of tics on employment status
Storch et al, 2007	United States	Specialist clinic	59 (+296 psychiatry controls) (+386 healthy controls)	11; 8–17	69%	42%	48%	PedsQL	QoL in patients with TS (and those with psychiatric disorders) worse than in healthy controls; QoL domains most affected: psychological, social, school; stronger parent-child agreement for QoL ratings in younger children (aged 8–11); parent-rated school functioning likely overestimated due to comorbid ADHD
Bernard et al, 2009	United States	Specialist clinic	56	10; 5–17	92%	9%	64%	TACQOL-PF	QoL affected by comorbid ADHD and OCD but not tic severity
Cutler et al, 2009	United Kingdom	Specialist clinic	57 (+1033 PedsQL normative data)	11; 8–17	80%	18%	32%	PedsQL	QoL in patients with TS worse than in healthy controls; QoL domains most affected: physical, psychological, social, school; psychological domain linked to school due to bullying; reported difficulty in fulfilling society’s expectations
Pringsheim et al, 2009	Canada, United States	Specialist clinic	71 (+391 CHQ normative data)	11; 7–17	79%	41%	56%	CHQ	QoL in patients with “TS only” similar to national norms; QOL in patients with TS + ADHD and TS + ADHD + OCD worse than national norms; QoL domain most affected: social; physical domain not affected; QoL affected by comorbidities
Müller-Vahl et al, 2010	Germany	Specialist clinic	200	35; 18–75	75%	NA	NA	EQ-5D	QoL domains most affected: physical, psychological; higher ratings of anxiety and depression compared with the general population
Conelea et al, 2011	United States	Online survey	232	12; 10–17	83%	39%	37%	PedsQL	QoL domains most affected: psychological, social, school; QoL affected by family functioning
Eddy et al, 2011	Italy	Specialist clinic	50	13; 10–17	88%	48%	52%	YQOL-R	QoL affected by depression and comorbid ADHD and OCD but not tic severity
Eddy et al, 2011	Italy	Specialist clinic	50 (+50 epilepsy controls) (+102 healthy controls)	13; 10–17	88%	48%	52%	YQOL-R	TS can be associated with poorer perceived QoL than healthy/epilepsy controls; QoL domains most affected: physical, psychological, social; reduced social interaction and participation in activities
Eddy et al, 2012	Italy	Specialist clinic	50	13; 10–17	88%	48%	52%	YQOL-R	QoL affected by combined effect of comorbid ADHD and OCD, through their impact on social relationships
Jalenques et al, 2012	France	Postal survey	167 (+3560 nationally representative sample)	29; 16–68	74%	NA	NA	WHOQOL-26; FSQ	QoL domains most affected: physical, psychological, social, occupational; impact of depression on QoL; the quality of social interactions rated as very poor
Rizzo et al, 2012	Italy	Specialist clinic	100	16; 13–18	86%	47%	3%	YQOL-R	QoL affected by comorbid conditions (shift from ADHD to OCD at 10-y follow-up)
Zinner et al, 2012	United States	Online survey	201	12; 10–17	81%	NA	38%	PedsQL	Peer victimization is associated with poorer QoL greater tic frequency, complexity and severity, explosive outbursts, and internalizing symptoms
Conelea et al, 2013	United States	Online survey	672	35; 18–77	59%	35%	23%	PQOL	QoL domains most affected: physical, psychological, social, cognitive, occupational; impact of tics on occupation
McGuire et al, 2013	United States	Specialist clinic	99	12; 8–17	80%	42%	44%	PedsQL	Social deficits in youngsters with tics predict QoL above and beyond tic severity; social deficits are greater in those with ADHD and OCD and partially mediate the relationship between tic severity and QoL
Conelea et al, 2014	United States	Online survey	509	37; NA	59%	NA	NA	PQOL	Tic-related general and social activity restriction are significantly correlated with lower QoL and poorer emotional functioning, regardless of tic severity
Hesapçıoğlu et al, 2014	Turkey	Specialist clinic	57 (+57 healthy controls)	NA; 6–16	NA	NA	NA	PedsQL	Poorer QoL in patients with chronic tics than controls (except for emotional and social functionality domains) but no association between tic severity and QoL
Rizzo et al, 2014	Italy	Specialist clinic	92 (+102 healthy controls)	13; 7–17	66%	28%	28%	YQOL-R	Poorer QoL in patients with TS than controls; QoL domains most affected: psychological, social; impact of emotional lability on QoL
Gutierrez-Colina et al, 2015	United States	Summer camp	36 (+10241 PedsQL normative data)	13; 8–18	69%	47%	58%	PedsQL	Poorer QoL in patients with TS than controls; QoL domains most affected: psychological, social, cognitive, school (no assessment of tic severity)
O’Hare et al, 2016	Australia	Postal survey	86 (+108 healthy controls)	11; 7–16	85%	NA	NA	PedsQL	Youth with TS experience lower QoL, increased emotional, behavioral and social difficulties, and elevated rates of insecure peer attachment relative to controls, as reported by their primary caregiver; association between insecure attachment to peers, increased tic severity, presence of comorbidities, and adverse QoL outcomes
O’Hare et al, 2016	Australia	Postal survey	86	11; 7–16	85%	NA	NA	PedsQL	Association between comorbidity and decreased global QoL, impaired emotional and school functioning, and increased emotional symptomatology
Liu et al, 2017	China	Specialist clinic	107 (+107 healthy controls)	10; NA	86%	43%	19%	ISQL	Poorer QoL in patients with TS than controls; QoL domains most affected: physical, psychological, social, school; impact of family stress and social withdrawal on QoL
Doja et al, 2018	Canada	Specialist clinic	13	NA; 8–16	62%	NA	NA	PedsQL	Higher physical activity levels are associated with improved aspects of QoL (physical, social, school, and psychosocial functioning)
Erbilgin Gün and Kilincaslan, 2019	Turkey	Specialist clinic	54	12; 7–18	83%	39%	100%	PedsQL	Children with TD and ADHD have lower QoL than their peers with ADHD alone; family functioning affects QoL in both groups
Huisman-van Dijk et al, 2019	Holland	Specialist clinic	187	37; 18–65	61%	38%	NA	EQ-5D	Depression (but not tic severity) directly reduces QoL; anxiety and OCD symptom severity have an indirect effect on QoL, mediated by depression
Lee et al, 2020	South Korea	Specialist clinic	56	12; 8–23	84%	NA	NA	KIDSCREEN-52-HRQOL	Depression, anxiety, tic severity, and expressed emotions negatively affect QoL
Vermilion et al, 2020	United States	Specialist clinic	205 (+100 healthy controls)	11; NA	76%	38%	43%	CHQ, PedsQL	Psychosocial and physical QoL are lower in patients with tics compared with controls; severity of ADHD and depression are associated with lower psychosocial QoL
Liu et al, 2023	China	Specialist clinic	363	8; 4–16	80%	NA	NA	PedsQL	Age, presence of chronic conditions, tic severity, comorbid behavioral problems, parental involvement in care, paternal and maternal education level, parenting pattern, and family relationship as main determinants of QoL
Conte et al, 2024	Italy	Specialist clinic	80	11; 6–16	90%	29%	24%	PedsQL	Depression, anxiety, and disease duration as main predictors of poorer QoL
Watson et al, 2024	United States	Specialist clinic	38 (+28 healthy controls)	15; 13–16	63%	50%	55%	YQOL-R	Psychosocial factors, tic severity and family history of tics predict poorer QoL in adolescents with TS compared with controls

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

Genetics of Tourette Syndrome Evidence-Based Assessment of Tourette Syndrome Evidence-Based Behavior Therapy for Tourette Syndrome Pharmacotherapy for Tourette Syndrome Mindfulness-Based Interventions for Tourette Syndrome The Role of CBGTC Synaptic Neurotransmission in the Pathophysiology of Tics

Stay updated, free articles. Join our Telegram channel

Join