Table 2.
Description of the scales and measures commonly used in studies
| Scale | Description |
|---|---|
| Alzheimer’s disease assessment scale-cognitive (ADAS-cog) | The ADAS-cog is a frequently used test that measures cognition in clinical trials for new medications, interventions, and in research studies. It is comprised of 11 parts that primarily measures memory and language. It was developed as an outcome measure to antidementia therapies as a two-part scale: one that measures non-cognitive functions and another that measures cognitive functions. |
| Clinical dementia rating (CDR) | The CDR is a 5-point scale that assesses cognitive and functional performance of individuals with Alzheimer disease and related dementias. It characterizes six domains—memory, personal care, community affairs, home and hobbies, orientation, and judgment and problem solving. The information to rate each is collected via an interview and reliable collateral sources. |
| Clinical global impressions (CGI) | Overall clinician-determined summary that measures symptom severity and treatment response. It also provides a brief summary of the clinician’s assessment of a patient with a mental disorder before and after starting a study medication. The summary considers the patient’s history, symptoms, behavior, psychosocial circumstances, and how the symptoms impact a patient’s functionality. |
| Disability assessment for dementia (DAD) | The DAD scale is an informant-based interview that includes instrumental and basic ADL items used to diagnose and assess patients with dementia or MCI. It evaluates the activities that are problematic followed by addressing aspects of performance that are impaired. |
| Dementia rating scale (DRS) | The dementia rating scale is designed to evaluate the level of cognitive functioning for persons with brain dysfunction. It is a 36-task and 32-stimulus card individually administered instrument capable of differentiating the extent of deficit and is also sensitive at the lower ends of functioning. |
| Epworth sleepiness scale (ESS) | The Epworth sleepiness scale is a questionnaire that measures an individual’s overall level of daytime sleepiness. |
| Frontal assessment battery (FAB) | The FAB consists of six neuropsychological tasks designed to explore the behavioral and cognitive domains of executive functioning and thereby assess frontal lobe function at bedside. The six domains tested are inhibitory control, environmental autonomy, conceptualization, mental flexibility, self-regulation and resistance to interference, and motor programming and executive control of action. |
| Goal attainment scaling (GAS) | Idiographic approach for measuring outcomes of psychosocial interventions in community settings. The patient’s goals are assigned to a behavioral expectation that ranges from a point scale of best (+2) to worst possible outcome (−2)1. |
| Hamilton depression rating scale (HAM-D) | The HAM-D is a multiple item questionnaire designed for adults to rate the severity of their depression and is also used as a means to assess recovery. It is the most commonly used scale to evaluate the efficacy of antidepressant therapy via symptom severity. |
| Mini-mental state examination (MMSE) | This is a 30-point questionnaire used in research and clinical settings in order to measure cognitive impairment, estimate progression and severity of cognitive impairment, and follow the course of cognitive changes over time for each individual. It is an effective method to record an individual’s response to treatment, by examining orientation, registration, attention and calculation, recall, language, and ability to follow simple commands. |
| Parkinson’s disease questionnaire-8 (PDQ-8) | The PD questionnaire-8 is a self-administered shortened version of Parkinson disease questionnaire-39 that consists of one selected item from each of the 8 quality of life dimensions of the PDQ-39. It is less time consuming, more easily administered, and measures the quality of life for individuals with Parkinson’s disease. |
| Parkinson’s disease quality of life scale-39 (PDQ-39) | The PDQ-39 is a 39-item self-report comprehensive Parkinson’s disease assessment questionnaire that evaluates how patients experience difficulties, and the impact of Parkinson’s disease (PD) across eight specific dimensions of functioning and well-being. It is based on statistical criteria of 39-multiple-choice items covering 8 dimensions, mainly used in clinical trials. |
| Neuropsychiatric inventory (NPI) | The NPI is a structured, caregiver-based interview designed to detect, quantify and assess changes of psychiatric symptoms within a demented population. It evaluates 10 behavioral domains—delusions, hallucinations, agitation/aggression, anxiety, irritability, euphoria, apathy, dysphoria/depression, disinhibition, and aberrant motor behavior. Often, two other domains are included—weight changes and nighttime behavioral disturbance (NPI-12). A lower score is better. |
| The unified Parkinson’s disease rating scale (UPDRS-I & II) | The UPDRS follows the longitudinal course of Parkinson’s disease and it is the most commonly applied rating scale for PD. Higher score signifies more severe Parkinsonism. Clinicians utilize it to follow the progression of individuals with PD, while researchers use it to measure changes from interventions. It is comprised of 31 items contributing to three subscales: (I) Behavior, Mentation, and Mood; (II) Activities of Daily Living; and (III) Motor Examination. It provides insight to the patient’s disease progression while sensitive to change over time. |
| Verbal fluency test | The verbal fluency test is a psychological test whereby patients categorically produce as many words as possible within a certain time frame. The category can be phonemic such as words beginning with a specific letter, or semantic like an object. Even though the total number of words is used to measure performance, other analyses like length and number of clusters of words from the same subcategory or number of repetitions can be performed. |
| Zarit burden inventory (ZBI) | The ZBI is a measure of caregiver burden for individuals with dementia. Multiple versions have been published, which feature statements that are ranked by informants, with higher scores reflecting greater caregiver burden. It has also been used in a number of other applications, such as outcome measures for drug trials and specific patient groups. |