Table 2.

Proposed measures for a neuroclinical assessment of FMD.

Measure	Time to Complete	Type of Task
Negative Valence System
Approach Avoidance Task (AAT) (Rinck and Becker, 2007)	10 minutes	Behavioral
This task measures approach and avoidance tendencies (movements) toward positively and negatively valenced stimuli.
Trier Social Stress Test (TSST) (Kirschbaum et al., 1995)	20 minutes	Behavioral
The TSST is a well-established procedure evoking a robust psychological and neuroendocrine response to acute stress. It incorporates social evaluation and unpredictability (mock job interview in front of an unresponsive audience and a surprise mental arithmetic test).
Cold Pressor Task (Lovallo, 1975)	10 minutes	Behavioral
This is a pain tolerance task which also evoke a robust stress response. Pain is often reported by patients with FMD and other FND, thus this task could be a useful tool to investigate the overlap between dysregulated stress response and pain.
Toronto Alexithymia Scale (TAS) (Bagby et al., 1994)	5 minutes	Self-Report
The TAS is a self-report questionnaire designed to measure the three components of alexithymia: difficulty identifying and distinguishing emotions from bodily sensations; difficulty describing and verbalizing emotions; and externally oriented thinking. Thus, the constructs assessed by this scale span across several RDoC domains (negative valence, social processes).
Childhood Trauma Questionnaire (CTQ) (Bernstein et al., 2003)	5 minutes	Self-Report
The CTQ is one of the most widely used self-reports of early adversity used in research settings. This questionnaire measures five types of maltreatment: emotional, physical, and sexual abuse, and emotional and physical neglect.
Facial Emotion Matching Task (Hariri et al., 2002)	10 minutes	Neuroimaging
This emotional matching paradigm, introduced by Hariri and colleagues in 2000, is a widely used neuroimaging experiment that reliably activates the amygdala. In the classic version of the experiment faces with negative emotional expression and scenes depicting distressing events are compared with geometric shapes instead of neutral stimuli of the same category (i.e., faces or scenes). This paradigm has been previously used in several studies in FMD and other FND patients.
Beck Depression Inventory (BDI) (Beck et al., 1988a)	5 minutes	Self-Report
This is a self-report rating inventory that measures symptoms of depression. The BDI has been validated in a range of clinical and non-clinical populations and has been included among the recommended outcome measure for FND.
Beck Anxiety Inventory (BAI) (Beck et al., 1988b)	5 minutes	Self-Report
The BAI is a self-report scale used to assess the severity of anxious symptomatology. As the BDI, it is also included among the recommended outcomes measures for FND.
Life Events and Difficulties Schedule(LEDS) (Nicholson et al., 2016)	30–120 minutes	Semi-structured interview
The LEDS system employs a semi-structured interview that systematically covers life domains and potential stressors. Next, the interviewer presents the reported events and chronic difficulties to a panel of raters who judge each stressor.
Fear conditioning/ extinction paradigm (Schiller et al., 2008)	3– 4 days	Behavioral/Neuroimaging
Standard fear conditioning paradigms are commonly used to study the regulation and inhibition of fear memories. They include three phases: 1) Fear acquisition, 2) Extinction and 3) Extinction Retention.
Facial expression detection (via electromyography or software) in response to visual stimuli and/or after stress-evoking procedures (Ree et al., 2019) (Mayo et al., 2020),	10–15 minutes	Psychophysiological
Facial reactions in response to facial expressions or other emotional valenced stimuli represents an index of affective states and can be measured objectively using Electromyography (EMG) or software.
Cognitive System
Stop Signal Reaction Task (SSRT) (Verbruggen and Logan, 2008)	10 minutes	Behavioral
The SSRT measures inhibition of a response that has already been initiated (action cancellation). This task elicits an early activation of attentional mechanisms followed by an engagement of motor control processes.
Go-No Go Task (GNGT) (van Wouwe et al., 2020)	10 minutes	Behavioral
Similar to the SSRT, the GNGT is also used to measure response inhibition, although this task captures action restrain (decision whether to respond or not). The GNGT appears to mainly rely on cognitive control mechanisms.
Continuous Performance Test (Riccio et al., 2002)	15 minutes	Behavioral
This test is commonly used to assess attention performances in the areas of inattentiveness, impulsivity, sustained attention, and vigilance.
Beads in a Jar Task (Pareés et al., 2012b)	5 minutes	Behavioral
This is a well-studied probabilistic reasoning paradigm, which is used to measure the ‘jumping to conclusion’ bias, a tendency to make decisions with certainty based on insufficient information.
Rapid Visual Information Processing Task (Hilti et al., 2010)	7 minutes	Behavioral/Neuroimaging
This task is a serial detection task used to probe visual sustained attention and working memory processes.
Attentional blink and psychological refractory period paradigm (Dual Task) (Marti et al., 2012)	Variable (minutes)	Behavioral/Neuroimaging
This paradigm is used to test dual-task interference in sensory consolidation (e.g., the attentional blink, AB) and response selection (e.g., the psychological refractory period). Dual-tasking relies on cognitive control and attentional processes.
Behavior Rating Inventory of Executive Function-Adult Version (Løvstad et al., 2016)	10–15 minutes	Self-Report
This inventory, which include self- and informant-report versions, assesses executive dysfunction in daily life.
Arousal and Regulatory Systems
Psychomotor Vigilance Task (PVT) (Loh et al., 2004)	10 minutes	Behavioral
The PVT is a sustained visual vigilance/attention reaction-time test used to measure behavioral alertness, particularly in the context of sleep loss.
POMS arousal subscale (McNair et al., 1971)	5 minutes	Self-Reported
This is one of the 6 subscales of the Profile of mood state (POMS), a self-report inventory measuring transient and distinct changes in mood.
Pittsburgh Sleep Quality Index (PSQI) (Buysse et al., 1989)	5 minutes	Self-Reported
The PSQI is a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval.
Electrodermal responding	Variable (minutes)	Psychophysiological
The electrodermal response, also known as skin conductance response, occurs in response to either external or internal arousing stimuli. It is an indirect measure of sympathetic autonomic activity that is associated with both emotion and attention.
Heart rate variability (HRV) (Maurer et al., 2016b)	Variable (minutes)	Psychophysiological
HRV is an index of cardiac vagal tone, which is relevant for both physiological and emotional arousal.
Sensorimotor System
Action Recognition Paradigm (Synofzik et al., 2010)	10 minutes	Behavioral/Neuroimaging
This experimental paradigm is used to assess the ability of a subject to distinguish whether or not a sensory event has been selfproduced, thus it is considered a measure of the sense of agency.
Force matching task (Pareés et al., 2014)	Variable (minutes)	Neurophysiological/Neuroimaging
This task, in which subjects are asked to match perceived force with self-generated force, is a measure of sensory attenuation (SA), which is the reduction in the perceived intensity of stimuli generated by one’s actions, compared to externally generated stimuli. Thus, SA relates to sense of agency.
Intentional binding (IB) paradigms (Hughes et al., 2013)	Variable (minutes)	Neurophysiological/Neuroimaging
In a standard IB paradigm, subjects are requested to provide estimates, direct numerical judgements or motor responses (pressing a key) corresponding to the perceived temporal interval between the voluntary action and the external sensory consequence.
Action monitoring task with visual feedbacks of the movement (Mahon et al., 2020)	Variable (minutes)	Neurophysiological/ Neuroimaging
This experimental paradigm is used to investigate how sensory information regarding an action (e.g., visual information about target position) is integrated to monitor the consequences of an action, that is motor control.
The sense of agency scale (Tapal et al., 2017)	5 minutes	Self-Reported
This scale quantifies perceived control over one’s mind, body, and the immediate environment.
Interoception Attention Task* (Avery et al., 2014)	20 minutes	Neuroimaging
This fMRI task has been designed to investigate the neural correlates of interoceptive attention toward visceral sensations vs. brain response patterns underlying exteroceptive attention to visually presented targets.
Multidimensional Assessment of Interoceptive Awareness*(Mehling et al., 2012)	5 minutes	Self-Reported
This scale is a self-report measure of interoceptive body awareness.

^*The interoception construct is currently not included in any RDoC domain.