Neuropsychological tests
All the neuropsychological assessments were performed prior to ADT and
at the third and sixth months of ADT. Four neuropsychological tests,
including the Symbol Digit Modalities Test (SDMT) [10], the
California Verbal Learning Test, second edition (CVLT-II) [11]; the
Brief Visuospatial Memory Test - Revised (BVMT-R) [11]; and the
Trail Making Test (TMT) [12,13]were performed to cover 4 main
cognitive areas. Depressive symptoms were measured using the Beck
Depression Inventory (BDI) [14]. All the neuropsychological tests
were completed in approximately 15–20 min in the supervision of trained
physicians.
Attention and speed of processing : A written version of the
SDMT was used to assess visual spatial scanning, attention and
concentration, and information processing speed. Patients were asked to
match as many symbols with digits 1–9 as possible in 90 s. The SDMT
takes approximately 5 min to complete. The test result represents the
number of correct answers [10].
Verbal memory : The CVLT-II is the standard scale of verbal
learning and memory in clinical neuropsychology and has been widely used
in clinical trials. The CVLT-II is composed of a 16-item word list. The
examiner reads out the list of words to the participant in the same
order. After each reading, the patient repeats as many words as possible
in any order. The learning score represents the total number of correct
words remembered in the first 5 attempts [11].
Visuospatial learning and memory : BVMT-R is a measurement tool
of visuospatial learning and memory; it consists of 3 recall attempts.
At the learning attempts, patients were asked to view 6 geometric
figures for 10 s. Then they were asked to draw as many symbols as they
can remember, in the correct position on an empty page. These drawn
symbols are scored from 0 to 2, depending on accuracy and location, for
a maximum of 12 points for each attempt to recall and draw the 6
figures. The highest possible score is 36 total for 3 recall attempts
[11].
Executive functions: Executive functions comprise working
memory, complex attention, problem solving, and response inhibition. The
TMT evaluates visual search, attention, and executive function and is
divided into 2 parts. The first part of the test evaluates speed and
psychomotor attention and requires consecutively connecting
randomly-distributed, encircled numbers from 1 to 25 [12]. The
second part requires the subject to connect numbers and letters in
alternating, ascending order [13]. Patients were asked to finish the
test as quickly as possible, and the test time was recorded. A
standardization study of this test in Turkish adults over the age of 50
was conducted by Cangöz et al [15].
Depressive symptoms : The BDI is used to assess depressive
symptoms. In this scale, patients were asked to mark the most accurate
expressions describing how they felt in the week leading up to and
including the day of the test. The BDI test consists of 21 questions,
with the following possible responses: not at all (0); mild (1);
moderate (2), and severe (3). According to the scoring system, a 0–10
score is considered normal, 11–16 is mild mood disturbance, 17–20 is
borderline mood, 21–30 is moderate depression, 31–40 is severe
depression, and ≥41 is extreme depression [14].