Movement Disorders
Vol. 6 , No. 1, 1991, pp. 60-64
0 1991 Movement Disorder Society
Orthostatic Tremor: An Association with Essential Tremor Patricia M. FitzGerald and Joseph Jankovic Department of Neurology, Baylor College of Medicine, Houston, Texas, U.S.A.
Summary: Orthostatic tremor is characterized by tremor of the trunk and legs while standing. Rapid frequency has been emphasized as an important criterion for the diagnosis of this tremor. We observed five patients who had the typical findings of orthostatic tremor but had a wide range of frequencies. All five also had postural hand tremor and a family history of essential tremor, suggesting a relationship between orthostatic tremor and essential tremor. This report also emphasizes the association of orthostatic tremor with painful cramps and a relatively consistent improvement with clonazepam. Key Words: Essential tremor-Orthostatic tremor.
Orthostatic tremor (OT) was described in 1984 by Heilman in three patients with trunk and leg tremor, present only while standing and relieved by walking, sitting, and lying down (1). Clonazepam was of considerable benefit in two of the three patients. Subsequent reports have confirmed these findings (2-6). A very rapid frequency (14-18 Hz) has been emphasized as an important and possibly distinguishing feature of this tremor (2,4-6). We observed five patients with OT and essential tremor (ET). These patients provide evidence that OT is a variant of ET and that like ET, it has a variable frequency.
secondary to prior alcohol use. He was treated with clorazepate, propranolol, chlordiazepoxide, cyclobenzaprine, and diazepam, without relief. Finally, clonazepam markedly reduced the tremor amplitude. His mother had upper and lower extremity tremor and body tremor. His father had nocturnal myoclonus. On examination he had no tremor at rest, but after standing for 30 s, a 15-20 Hz tremor appeared in his legs associated with painful spasms in both calves. He had marked contraction (a painful cramp) involving his legs, particularly the gastrocnemius muscles. The tremor and cramp were relieved almost immediately after sitting, and were absent in a horizontal position. A flexion-extension 8-9-Hz tremor was present in the hands when arms were held in an outstretched posture. Electromyography (EMG) revealed an alternating 18-20-Hz tremor recorded in the flexors and extensors of both legs while standing. Primidone (300 mg/day) was added to the clonazepam (5 mg/day) and additional clinical improvement was noted.
CASE REPORTS
Patient 1 Thirty-five years ago this 60-year-old man noted severe leg tremor while kneeling at his wedding. The tremor recurred 24 years later, 11 years prior to our evaluation. An examination 2 years later was remarkable only for tremor in his legs while standing. Thyroid function tests and other laboratory studies were normal. A mild axonal neuropathy was noted on nerve conduction studies, presumably ~
Patient 2 A 46-year-old man has had action hand tremor since early childhood. At age 31 the right-hand tremor increased and 7 years later he noted tremor
~
Address correspondence and reprint requests to Dr. J. Jankovic, Department of Neurology, Baylor College of Medicine, 6550 Fannin, Suite 1801, Houston, TX 77030, U.S.A.
60
ORTHOSTATIC AND ESSENTIAL TREMOR in his legs while standing. This OT became more disabling than the hand tremor because he could not stand at meetings, in church, or at social functions. He also had lip and voice tremor. Modest improvement in all symptoms was noted with alcohol, propranolol (40 mg/day), and diazepam (I0 mg/day). The leg tremor appeared almost immediately after assuming a standing position, and persisted unless the patient sat or lay down. The tremor was associated with a cramping pain in the legs and the discomfort resolved several minutes after he rested. His mother and two daughters had hand tremor, his father had leg tremor, and his sister had tremor in her arms, legs, and voice. A 12-14-Hz tremor was noted in both legs as soon as he stood up. This was associated with painful contraction in his hamstrings and calves. In addition, he had an 8-9-Hz hand tremor, seen when his arms were extended in front of him, in the “wing beating” position, and on a “finger-to-nose” testing. Tremor recording on standing revealed a 1214-Hz rhythmic nonalternating tremor in the quadriceps, hamstring, and anterior tibia1 and gastrocnemius muscles. Three months later, he no longer had OT while taking primidone, 150 mg/day, and clonazepam, 3 mglday. This improvement continued 9 months later. Patient 3 A 70-year-old man has had tremor in both legs for 5 years. The tremor is induced by standing for 2-3 min and it is relieved by walking or sitting down. His father and father’s brother had had hand action tremor in their old age. Clonazepam improved the tremor but it had to be discontinued because of fecal incontinence. He had a modest improvement with phenobarbital. On examination, he had a fine 8-9-Hz tremor of his hands when his arms were held in the outstretched position. After standing for 3-4 min,
R Quad. L Quad.
+- I 1 Sec FIG. 1. EMG recording in patient 4 showing synchronous 14-Hz tremor in proximal leg muscles.
61
R A. Tib. R Gastro.
0.5 sec FIG. 2. EMG recording in patient 4 showing synchronous 14Hz tremor in distal flexors and extensors of right leg.
marked tremor developed in both legs. Surface EMG of leg muscles during standing showed a 12Hz tremor that was asynchronous in the two legs. Treatment with primidone, up to 750 mg daily, did not improve the tremor. He is presently taking sodium valproate, without significant benefit. Patient 4 A 56-year-old woman with a long-standing history of bilateral hand tremor noted tremor in her legs while standing 5 years ago. At onset, there was a latency of about 30 min after standing before her symptoms occurred. However, this progressed such that leg tremor developed immediately on standing, precluding her ability to carry out any household tasks or shopping. In addition to the leg tremor, she also complained of hand tremor, particularly if she was under stress. The leg tremor resolved while sitting or lying down. Because of painful cramps in the distal part of her legs and stiffness in her back, her gait was restricted and she walked with a narrow base and short steps. Her tremor improved slightly with alcohol and propranolol. Her mother, younger brother, and one of her sons have had hand tremor. Postural tremor was present in her hands when arms were outstretched or in a “wing-beating” position. In the supine position, with her legs elevated about 30°, she again had marked tremor. Tremor with marked spasm in her calf muscles was noted when she flexed her feet against resistance. On standing, she immediately had leg tremor with painful spasm in the anterior and posterior distal part of the leg muscles. She walked with a narrow base and short steps and expressed a fear of falling. Symptoms were almost immediately relieved after she sat down. Surface EMG recordings while she was
Movement Disorders, Vol. 6, No. 1, 1991
P . M . FITZGERALD AND J . JANKOVIC
standing demonstrated a synchronous 14-Hz tremor in all extremities (Figs. 1, 2). Six weeks after starting clonazepam therapy (3 mg/day), she had marked improvement in her ability to stand and walk, and she no longer had any restriction in her lifestyle.
On examination he had postural tremor with a frequency of 8 Hz in both hands. Minimal tremor was evident in his legs when he held them against gravity. When he stood up, bilateral leg tremor developed after approximately 9 s. This was associated with severe contraction of the gastrocnemius and soleus, in addition to his tibialis anterior, quadriceps, and hamstring muscles. If he shifted from leg to leg, leaned against the wall, walked, sat down or lay down, the tremor transiently stopped. Clonazepam, 3 mglday , produced moderate improvement.
Patient 5 This 68-year-old man began to notice difficulty with standing 4 years prior to our evaluation. Initially, the latency from standing to onset of leg tremor was several minutes; however, this latency had shortened to less than 30 s. Because of the leg (and trunk) tremor he is unable to stand at cocktail parties, do public speaking, and ski for more than 200 yd without sitting or lying down. In addition, he obtains relief by leaning against a support, walking, or even shifting weight from one leg to another. Alcohol transiently ameliorates his symptoms. Other than a mild hand tremor for several years, he had been neurologically well. His mother had moderate postural hand tremor appearing late in life.
DISCUSSION Since the original report of three patients by Heilman (I), several other patients have been described and a characteristic clinical picture of OT has emerged (Tables I and 2) (1-1 1). Among the 27 of 46 patients with OT described in the literature, women outnumbered men 17:lO and the mean age at onset was 55 years (range, 38-74). The reported fre-
TABLE 1. Clinical characteristics of orthostatic tremor
Author($, yr Heilman (I), 1984 Thompson et al. (2), 1986 Wee et al. (3), 1986 Deuschl et al. (6), 1987 Kelly and Sharbrough (3,1987 Koller et al. (7), 1987 Martinelli et al. (8), 1987 Papa and Gershanik (4), 1988 Van der Zwan et al. (9), 1988 Cleeves et al. (lo), 1989 Uncini et al. (Il), 1989 Fitzgerald and Jankovic (present study), 1991
Patient no. 1
2 3 1 1
2 1 19 1
2 3 1-5 1 3 2
Age, Yr
Duration of symptoms, Yr
Family history of ET"
EMG frequency, Hz
Several seconds NM Several seconds Few minutes Within a few seconds NM 5-20 s NM
113
NM
011 212
116 6-7
55 53 70 48 NM
NM 9 15 6 NM
F M F M F F F NM
65 56 51 NM (mean 64.5) 63
1 8 7 NM
F F F 3F12M
7
F
A few seconds
68 72
1.5 NM 3
F F M
A few seconds A few seconds Within 1 min
63 78 74
20
Sex
Latency from standing to onset of tremor
10 10
20 s NM NM NM
1
77
1
15
2 I
53 73 64 60
0.5 2 11
F M F M
NM A few seconds A few seconds 30 s
2
46
8
M
10 s
3 4 5
70 56 68
5 5 4
M F M
2-3 min Immediate 30 s
1
ET, essential tremor; EMG, electromyography; NM, not mentioned. Number with family history of the number of patients observed.
a
Movement Disorders, Vol. 6 , No. 1 , 1991
Other tremor Handiarm 0 0 Arm Lipslarm 0 Hand NM
Ill NM
8-16 14-18
NM
NM
1/5
NM
113
15-16
Hand Hand 0 Hand/head Voice/jaw Arm/head
011
NM
Arm Arm Hand
l/l 0/2
6 8-16
Hand Hand
515
12-20
Hand Hand/lip Voice Hand Hand Hand
63
ORTHOSTATIC A N D ESSENTIAL TREMOR TABLE 2. Orthostatic tremor: treatment
Author(s), yr
No. of patients
Relieving factors
3
Sit, walk, lie down, lean Widen stance, lean, walk, sit, grasp support Lean, sit, lie down, walk Sit, lie down, walk, grasp support Lie down, walk Sit, walk Walking, rest Widen stance, lean, grasp support Sit, brisk walk Walk, lean, sit, rest Walk, sit, lie down, lean, widen stance Sit, lie down, walk, lean against support
Heilman (I), 1984 Thompson et al. (21, 1986 Wee et al. ( 3 ) , 1986 Deuschl et al. (61, 1987 Kelly and Sharbrough (3, 1987 Koller et al. (7), 1987 Martinelli et al. (8), 1987 Papa and Gershanik (4), 1988 Van der Zwan et al. (9), 1988 Cleeves et al. (lo), 1989 Uncini et al. ( I l ) , 1989 Fitzgerald and Jankovic (present study), 1991
5
Improvement with propranolol
Effect of ETOH
Improvement with clonazepam
012 NM
NM 01I
213 NM
011 011
012 NM
212 NM
NM 012 NM
NM 011 012
NM NM NM NM NM NM NM
213
314
111
+ 313
NM 313 111 lil
011 415
~~
ETOH, alcohol; NM, not mentioned.
quency of the tremor varied from 6 to 20 Hz, and 12 of 24 (50%) patients with OT had a family member with ET. Furthermore, a majority of patients with OT also have action tremors in other body parts besides the legs and trunk. In this study we provide additional evidence that OT is pathogenetically related to ET. The overlapping spectrum of frequencies and a family history of ET in OT patients and their relatives suggests that OT represents a task-specific variant of ET. Although the frequency of leg tremor in our patients with OT varied between 12-20 Hz, higher than the usual frequency of ET, all five of our patients had a typical ET postural hand tremor with 8-9-Hz frequency. In contrast to the female preponderance in reported cases, men outnumbered women 4 to 1 in our series. Similar to most previously described cases (1-4,6,7,9,1 l), all our patients noted leg tremor within seconds after assuming a standing position, but patient 3 had a latency of up to 4 min. Sitting, walking, lying, or a widening of stance alleviated not only the tremor but also the associated leg cramp (2,4). All our patients had a family history of ET among their firstdegree relatives. The clinical characteristics of OT have been relatively uniform in the reported series, but the recorded tremor frequencies have varied. Thompson et al. (2) reported a frequency of 16 Hz, slowing intermittently to 8 Hz, and Wee et al. (3), in their two patients, found a frequency of 6-7 Hz. Kelly and Sharbrough ( 5 ) reported a 14-18-Hz tremor in their 19 patients. In some cases, including ours, the
frequency of leg tremor is twice the frequency of hand tremor, suggesting that the leg tremor (OT) represents a harmonic of the hand tremor (ET). Because of the wide spectrum of frequencies, we feel that frequency should not be used as a necessary criterion for diagnosis of OT. Essential tremor is often associated with other neurologic disorders, including dystonia (12), but the painful cramping, as seen in four of our patients, was not associated with dystonic movement or postures. The mechanism of these painful cramps is unknown, but it is interesting to note that patient 1 , who had the most rapid (18-20-Hz) leg tremor, had the most severe and disabling leg cramps, whereas patient 3, with the slowest (12-Hz) tremor, had no cramps. This suggests that the painful cramps seen in some patients with OT represent a tetanic contraction of the calf muscles produced by the very rapid tremor. Although there are many clinical and physiologic similarities between OT and ET (Table 3), the pharmacologic profile seems different in the two disorders. Propranolol is the treatment of choice in ET, but OT usually does not improve with beta blockers (1,3,6,7,10,11). Similarly alcohol does not seem to relieve OT (2,3). In contrast, clonazepam is particularly useful in OT, but not in ET (1,3-5,7,9,10). In addition to responding to clonazepam, some of our and other patients also had improvement with primidone (6,9,10,11). Phenobarbital (4) and valproic acid (5) are also occasionally useful, but clonazepam remains the medication of choice in OT (1,4,7,9,10). Despite these pharmacologic differ-
Movement Disorders, Vol. 6 , No. I , 1991
P . M . FITZGERALD AND J . JANKOVIC
64
TABLE 3. Essential tremor (ET) versus orthostatic tremor (OT) ET Occurrence Exacerbated by standing Latency of onset after posture Family history of ET Associated neurological disorders Frequency, Hz Response to alcohol beta-blockers clonazepam primidone 0, absent; cellent.
Common 0 0
+ Dystonia, myoclonus, neuropathy 4-12
+++ +++ + ++
OT Rare
+ + +
Leg cramps 6-20 0
+ +++ ++
+ , present or good; + + , very good; + + + , ex-
ences, we believe that the common coexistence with typical ET in the same patient and the frequent occurrence of ET in family members support the conclusion that OT and ET share common pathogenetic mechanisms and that OT is a variant of ET.
Movement Disorders, Vol. 6 . N o . 1 , 1991
REFERENCES 1 . Heilman KM. Orthostatic tremor. Arch Neurol 1984;41:880881. 2. Thompson PD, Rothwell JC, Day BL, et al. The physiology of orthostatic tremor. Arch Neurol 1986;43:584-587. 3. Wee AS, Subramony SH, Cumer RD. “Orthostatic tremor” in familial-essential tremor. Neurology 1986;36: 1241-1245. 4. Papa SM, Gershanik 0s. Orthostatic tremor: an essential tremor variant? Movement Dis 1988;3:97-108. 5 . Kelly JJ Jr, Sharbrough FW. EMG in orthostatic tremor. Neuroiogy 1987;37:1434. 6 . Deuschl G, Lucking CH, Quintern J. Orthostatischer tremor: Klinik, Pathophysiologie und Therapie. EEG EMG 1987;18: 13-19. 7. Koller WC, Glatt S, Biary N, Rubino FA. Essential tremor variants: effect of treatment. Clin Neuropharmacol 1987; 10:342-350. 8. Martinelli P, Gabellini AS, Gulli MR, Lugaresi E. Different clinical features of essential tremor: a 200-patient study. Acta Neurol Scand 1987;75: 106-1 1 1 . 9. Van der Zwan A, Verwey JC, van Gijn J. Relief of orthostatic tremor by primidone. Neurology 1988;38: 1332. 10. Cleeves L, Cowan J, Findley LJ. Orthostatic tremor: diagnostic entity or variant of essential tremor? J Neurol Neurosurg Psychiatry 1989;52: 130-131. 1 1 . Uncini A, Onofrj M, Basciani M, Cutarella R, Gambi D. Orthostatic tremor: report of two cases and an electrophysiological study. Acta Neurol Scand 1989;79:119-122. 12. Lou JS, Jankovic J. Essential tremor: clinical correlates in 350 patients. Neurology 1991 (in press).
Vol. 6 , No. 1, 1991, pp. 60-64
0 1991 Movement Disorder Society
Orthostatic Tremor: An Association with Essential Tremor Patricia M. FitzGerald and Joseph Jankovic Department of Neurology, Baylor College of Medicine, Houston, Texas, U.S.A.
Summary: Orthostatic tremor is characterized by tremor of the trunk and legs while standing. Rapid frequency has been emphasized as an important criterion for the diagnosis of this tremor. We observed five patients who had the typical findings of orthostatic tremor but had a wide range of frequencies. All five also had postural hand tremor and a family history of essential tremor, suggesting a relationship between orthostatic tremor and essential tremor. This report also emphasizes the association of orthostatic tremor with painful cramps and a relatively consistent improvement with clonazepam. Key Words: Essential tremor-Orthostatic tremor.
Orthostatic tremor (OT) was described in 1984 by Heilman in three patients with trunk and leg tremor, present only while standing and relieved by walking, sitting, and lying down (1). Clonazepam was of considerable benefit in two of the three patients. Subsequent reports have confirmed these findings (2-6). A very rapid frequency (14-18 Hz) has been emphasized as an important and possibly distinguishing feature of this tremor (2,4-6). We observed five patients with OT and essential tremor (ET). These patients provide evidence that OT is a variant of ET and that like ET, it has a variable frequency.
secondary to prior alcohol use. He was treated with clorazepate, propranolol, chlordiazepoxide, cyclobenzaprine, and diazepam, without relief. Finally, clonazepam markedly reduced the tremor amplitude. His mother had upper and lower extremity tremor and body tremor. His father had nocturnal myoclonus. On examination he had no tremor at rest, but after standing for 30 s, a 15-20 Hz tremor appeared in his legs associated with painful spasms in both calves. He had marked contraction (a painful cramp) involving his legs, particularly the gastrocnemius muscles. The tremor and cramp were relieved almost immediately after sitting, and were absent in a horizontal position. A flexion-extension 8-9-Hz tremor was present in the hands when arms were held in an outstretched posture. Electromyography (EMG) revealed an alternating 18-20-Hz tremor recorded in the flexors and extensors of both legs while standing. Primidone (300 mg/day) was added to the clonazepam (5 mg/day) and additional clinical improvement was noted.
CASE REPORTS
Patient 1 Thirty-five years ago this 60-year-old man noted severe leg tremor while kneeling at his wedding. The tremor recurred 24 years later, 11 years prior to our evaluation. An examination 2 years later was remarkable only for tremor in his legs while standing. Thyroid function tests and other laboratory studies were normal. A mild axonal neuropathy was noted on nerve conduction studies, presumably ~
Patient 2 A 46-year-old man has had action hand tremor since early childhood. At age 31 the right-hand tremor increased and 7 years later he noted tremor
~
Address correspondence and reprint requests to Dr. J. Jankovic, Department of Neurology, Baylor College of Medicine, 6550 Fannin, Suite 1801, Houston, TX 77030, U.S.A.
60
ORTHOSTATIC AND ESSENTIAL TREMOR in his legs while standing. This OT became more disabling than the hand tremor because he could not stand at meetings, in church, or at social functions. He also had lip and voice tremor. Modest improvement in all symptoms was noted with alcohol, propranolol (40 mg/day), and diazepam (I0 mg/day). The leg tremor appeared almost immediately after assuming a standing position, and persisted unless the patient sat or lay down. The tremor was associated with a cramping pain in the legs and the discomfort resolved several minutes after he rested. His mother and two daughters had hand tremor, his father had leg tremor, and his sister had tremor in her arms, legs, and voice. A 12-14-Hz tremor was noted in both legs as soon as he stood up. This was associated with painful contraction in his hamstrings and calves. In addition, he had an 8-9-Hz hand tremor, seen when his arms were extended in front of him, in the “wing beating” position, and on a “finger-to-nose” testing. Tremor recording on standing revealed a 1214-Hz rhythmic nonalternating tremor in the quadriceps, hamstring, and anterior tibia1 and gastrocnemius muscles. Three months later, he no longer had OT while taking primidone, 150 mg/day, and clonazepam, 3 mglday. This improvement continued 9 months later. Patient 3 A 70-year-old man has had tremor in both legs for 5 years. The tremor is induced by standing for 2-3 min and it is relieved by walking or sitting down. His father and father’s brother had had hand action tremor in their old age. Clonazepam improved the tremor but it had to be discontinued because of fecal incontinence. He had a modest improvement with phenobarbital. On examination, he had a fine 8-9-Hz tremor of his hands when his arms were held in the outstretched position. After standing for 3-4 min,
R Quad. L Quad.
+- I 1 Sec FIG. 1. EMG recording in patient 4 showing synchronous 14-Hz tremor in proximal leg muscles.
61
R A. Tib. R Gastro.
0.5 sec FIG. 2. EMG recording in patient 4 showing synchronous 14Hz tremor in distal flexors and extensors of right leg.
marked tremor developed in both legs. Surface EMG of leg muscles during standing showed a 12Hz tremor that was asynchronous in the two legs. Treatment with primidone, up to 750 mg daily, did not improve the tremor. He is presently taking sodium valproate, without significant benefit. Patient 4 A 56-year-old woman with a long-standing history of bilateral hand tremor noted tremor in her legs while standing 5 years ago. At onset, there was a latency of about 30 min after standing before her symptoms occurred. However, this progressed such that leg tremor developed immediately on standing, precluding her ability to carry out any household tasks or shopping. In addition to the leg tremor, she also complained of hand tremor, particularly if she was under stress. The leg tremor resolved while sitting or lying down. Because of painful cramps in the distal part of her legs and stiffness in her back, her gait was restricted and she walked with a narrow base and short steps. Her tremor improved slightly with alcohol and propranolol. Her mother, younger brother, and one of her sons have had hand tremor. Postural tremor was present in her hands when arms were outstretched or in a “wing-beating” position. In the supine position, with her legs elevated about 30°, she again had marked tremor. Tremor with marked spasm in her calf muscles was noted when she flexed her feet against resistance. On standing, she immediately had leg tremor with painful spasm in the anterior and posterior distal part of the leg muscles. She walked with a narrow base and short steps and expressed a fear of falling. Symptoms were almost immediately relieved after she sat down. Surface EMG recordings while she was
Movement Disorders, Vol. 6, No. 1, 1991
P . M . FITZGERALD AND J . JANKOVIC
standing demonstrated a synchronous 14-Hz tremor in all extremities (Figs. 1, 2). Six weeks after starting clonazepam therapy (3 mg/day), she had marked improvement in her ability to stand and walk, and she no longer had any restriction in her lifestyle.
On examination he had postural tremor with a frequency of 8 Hz in both hands. Minimal tremor was evident in his legs when he held them against gravity. When he stood up, bilateral leg tremor developed after approximately 9 s. This was associated with severe contraction of the gastrocnemius and soleus, in addition to his tibialis anterior, quadriceps, and hamstring muscles. If he shifted from leg to leg, leaned against the wall, walked, sat down or lay down, the tremor transiently stopped. Clonazepam, 3 mglday , produced moderate improvement.
Patient 5 This 68-year-old man began to notice difficulty with standing 4 years prior to our evaluation. Initially, the latency from standing to onset of leg tremor was several minutes; however, this latency had shortened to less than 30 s. Because of the leg (and trunk) tremor he is unable to stand at cocktail parties, do public speaking, and ski for more than 200 yd without sitting or lying down. In addition, he obtains relief by leaning against a support, walking, or even shifting weight from one leg to another. Alcohol transiently ameliorates his symptoms. Other than a mild hand tremor for several years, he had been neurologically well. His mother had moderate postural hand tremor appearing late in life.
DISCUSSION Since the original report of three patients by Heilman (I), several other patients have been described and a characteristic clinical picture of OT has emerged (Tables I and 2) (1-1 1). Among the 27 of 46 patients with OT described in the literature, women outnumbered men 17:lO and the mean age at onset was 55 years (range, 38-74). The reported fre-
TABLE 1. Clinical characteristics of orthostatic tremor
Author($, yr Heilman (I), 1984 Thompson et al. (2), 1986 Wee et al. (3), 1986 Deuschl et al. (6), 1987 Kelly and Sharbrough (3,1987 Koller et al. (7), 1987 Martinelli et al. (8), 1987 Papa and Gershanik (4), 1988 Van der Zwan et al. (9), 1988 Cleeves et al. (lo), 1989 Uncini et al. (Il), 1989 Fitzgerald and Jankovic (present study), 1991
Patient no. 1
2 3 1 1
2 1 19 1
2 3 1-5 1 3 2
Age, Yr
Duration of symptoms, Yr
Family history of ET"
EMG frequency, Hz
Several seconds NM Several seconds Few minutes Within a few seconds NM 5-20 s NM
113
NM
011 212
116 6-7
55 53 70 48 NM
NM 9 15 6 NM
F M F M F F F NM
65 56 51 NM (mean 64.5) 63
1 8 7 NM
F F F 3F12M
7
F
A few seconds
68 72
1.5 NM 3
F F M
A few seconds A few seconds Within 1 min
63 78 74
20
Sex
Latency from standing to onset of tremor
10 10
20 s NM NM NM
1
77
1
15
2 I
53 73 64 60
0.5 2 11
F M F M
NM A few seconds A few seconds 30 s
2
46
8
M
10 s
3 4 5
70 56 68
5 5 4
M F M
2-3 min Immediate 30 s
1
ET, essential tremor; EMG, electromyography; NM, not mentioned. Number with family history of the number of patients observed.
a
Movement Disorders, Vol. 6 , No. 1 , 1991
Other tremor Handiarm 0 0 Arm Lipslarm 0 Hand NM
Ill NM
8-16 14-18
NM
NM
1/5
NM
113
15-16
Hand Hand 0 Hand/head Voice/jaw Arm/head
011
NM
Arm Arm Hand
l/l 0/2
6 8-16
Hand Hand
515
12-20
Hand Hand/lip Voice Hand Hand Hand
63
ORTHOSTATIC A N D ESSENTIAL TREMOR TABLE 2. Orthostatic tremor: treatment
Author(s), yr
No. of patients
Relieving factors
3
Sit, walk, lie down, lean Widen stance, lean, walk, sit, grasp support Lean, sit, lie down, walk Sit, lie down, walk, grasp support Lie down, walk Sit, walk Walking, rest Widen stance, lean, grasp support Sit, brisk walk Walk, lean, sit, rest Walk, sit, lie down, lean, widen stance Sit, lie down, walk, lean against support
Heilman (I), 1984 Thompson et al. (21, 1986 Wee et al. ( 3 ) , 1986 Deuschl et al. (61, 1987 Kelly and Sharbrough (3, 1987 Koller et al. (7), 1987 Martinelli et al. (8), 1987 Papa and Gershanik (4), 1988 Van der Zwan et al. (9), 1988 Cleeves et al. (lo), 1989 Uncini et al. ( I l ) , 1989 Fitzgerald and Jankovic (present study), 1991
5
Improvement with propranolol
Effect of ETOH
Improvement with clonazepam
012 NM
NM 01I
213 NM
011 011
012 NM
212 NM
NM 012 NM
NM 011 012
NM NM NM NM NM NM NM
213
314
111
+ 313
NM 313 111 lil
011 415
~~
ETOH, alcohol; NM, not mentioned.
quency of the tremor varied from 6 to 20 Hz, and 12 of 24 (50%) patients with OT had a family member with ET. Furthermore, a majority of patients with OT also have action tremors in other body parts besides the legs and trunk. In this study we provide additional evidence that OT is pathogenetically related to ET. The overlapping spectrum of frequencies and a family history of ET in OT patients and their relatives suggests that OT represents a task-specific variant of ET. Although the frequency of leg tremor in our patients with OT varied between 12-20 Hz, higher than the usual frequency of ET, all five of our patients had a typical ET postural hand tremor with 8-9-Hz frequency. In contrast to the female preponderance in reported cases, men outnumbered women 4 to 1 in our series. Similar to most previously described cases (1-4,6,7,9,1 l), all our patients noted leg tremor within seconds after assuming a standing position, but patient 3 had a latency of up to 4 min. Sitting, walking, lying, or a widening of stance alleviated not only the tremor but also the associated leg cramp (2,4). All our patients had a family history of ET among their firstdegree relatives. The clinical characteristics of OT have been relatively uniform in the reported series, but the recorded tremor frequencies have varied. Thompson et al. (2) reported a frequency of 16 Hz, slowing intermittently to 8 Hz, and Wee et al. (3), in their two patients, found a frequency of 6-7 Hz. Kelly and Sharbrough ( 5 ) reported a 14-18-Hz tremor in their 19 patients. In some cases, including ours, the
frequency of leg tremor is twice the frequency of hand tremor, suggesting that the leg tremor (OT) represents a harmonic of the hand tremor (ET). Because of the wide spectrum of frequencies, we feel that frequency should not be used as a necessary criterion for diagnosis of OT. Essential tremor is often associated with other neurologic disorders, including dystonia (12), but the painful cramping, as seen in four of our patients, was not associated with dystonic movement or postures. The mechanism of these painful cramps is unknown, but it is interesting to note that patient 1 , who had the most rapid (18-20-Hz) leg tremor, had the most severe and disabling leg cramps, whereas patient 3, with the slowest (12-Hz) tremor, had no cramps. This suggests that the painful cramps seen in some patients with OT represent a tetanic contraction of the calf muscles produced by the very rapid tremor. Although there are many clinical and physiologic similarities between OT and ET (Table 3), the pharmacologic profile seems different in the two disorders. Propranolol is the treatment of choice in ET, but OT usually does not improve with beta blockers (1,3,6,7,10,11). Similarly alcohol does not seem to relieve OT (2,3). In contrast, clonazepam is particularly useful in OT, but not in ET (1,3-5,7,9,10). In addition to responding to clonazepam, some of our and other patients also had improvement with primidone (6,9,10,11). Phenobarbital (4) and valproic acid (5) are also occasionally useful, but clonazepam remains the medication of choice in OT (1,4,7,9,10). Despite these pharmacologic differ-
Movement Disorders, Vol. 6 , No. I , 1991
P . M . FITZGERALD AND J . JANKOVIC
64
TABLE 3. Essential tremor (ET) versus orthostatic tremor (OT) ET Occurrence Exacerbated by standing Latency of onset after posture Family history of ET Associated neurological disorders Frequency, Hz Response to alcohol beta-blockers clonazepam primidone 0, absent; cellent.
Common 0 0
+ Dystonia, myoclonus, neuropathy 4-12
+++ +++ + ++
OT Rare
+ + +
Leg cramps 6-20 0
+ +++ ++
+ , present or good; + + , very good; + + + , ex-
ences, we believe that the common coexistence with typical ET in the same patient and the frequent occurrence of ET in family members support the conclusion that OT and ET share common pathogenetic mechanisms and that OT is a variant of ET.
Movement Disorders, Vol. 6 . N o . 1 , 1991
REFERENCES 1 . Heilman KM. Orthostatic tremor. Arch Neurol 1984;41:880881. 2. Thompson PD, Rothwell JC, Day BL, et al. The physiology of orthostatic tremor. Arch Neurol 1986;43:584-587. 3. Wee AS, Subramony SH, Cumer RD. “Orthostatic tremor” in familial-essential tremor. Neurology 1986;36: 1241-1245. 4. Papa SM, Gershanik 0s. Orthostatic tremor: an essential tremor variant? Movement Dis 1988;3:97-108. 5 . Kelly JJ Jr, Sharbrough FW. EMG in orthostatic tremor. Neuroiogy 1987;37:1434. 6 . Deuschl G, Lucking CH, Quintern J. Orthostatischer tremor: Klinik, Pathophysiologie und Therapie. EEG EMG 1987;18: 13-19. 7. Koller WC, Glatt S, Biary N, Rubino FA. Essential tremor variants: effect of treatment. Clin Neuropharmacol 1987; 10:342-350. 8. Martinelli P, Gabellini AS, Gulli MR, Lugaresi E. Different clinical features of essential tremor: a 200-patient study. Acta Neurol Scand 1987;75: 106-1 1 1 . 9. Van der Zwan A, Verwey JC, van Gijn J. Relief of orthostatic tremor by primidone. Neurology 1988;38: 1332. 10. Cleeves L, Cowan J, Findley LJ. Orthostatic tremor: diagnostic entity or variant of essential tremor? J Neurol Neurosurg Psychiatry 1989;52: 130-131. 1 1 . Uncini A, Onofrj M, Basciani M, Cutarella R, Gambi D. Orthostatic tremor: report of two cases and an electrophysiological study. Acta Neurol Scand 1989;79:119-122. 12. Lou JS, Jankovic J. Essential tremor: clinical correlates in 350 patients. Neurology 1991 (in press).
